[Federal Register Volume 83, Number 218 (Friday, November 9, 2018)]
[Proposed Rules]
[Pages 56156-56196]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2018-24076]
[[Page 56155]]
Vol. 83
Friday,
No. 218
November 9, 2018
Part II
Nuclear Regulatory Commission
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10 CFR Part 50
American Society of Mechanical Engineers 2015-2017 Code Editions
Incorporation by Reference; Proposed Rule
Federal Register / Vol. 83 , No. 218 / Friday, November 9, 2018 /
Proposed Rules
[[Page 56156]]
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NUCLEAR REGULATORY COMMISSION
10 CFR Part 50
[NRC-2016-0082]
RIN 3150-AJ74
American Society of Mechanical Engineers 2015-2017 Code Editions
Incorporation by Reference
AGENCY: Nuclear Regulatory Commission.
ACTION: Proposed rule.
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SUMMARY: The U.S. Nuclear Regulatory Commission (NRC) is proposing to
amend its regulations to incorporate by reference the 2015 and 2017
Editions of the American Society of Mechanical Engineers (ASME) Boiler
and Pressure Vessel Code (BPV Code) and the 2015 and 2017 Editions of
the ASME Operation and Maintenance of Nuclear Power Plants, Division 1:
OM: Section IST (OM Code), respectively, for nuclear power plants. The
NRC is also proposing to incorporate by reference two revised ASME code
cases. This action is in accordance with the NRC's policy to
periodically update the regulations to incorporate by reference new
editions of the ASME Codes and is intended to maintain the safety of
nuclear power plants and to make NRC activities more effective and
efficient.
DATES: Submit comments by January 23, 2019. Comments received after
this date will be considered if it is practical to do so, but the NRC
is able to ensure consideration only for comments received on or before
this date.
ADDRESSES: You may submit comments by any of the following methods
(unless this document describes a different method for submitting
comments on a specific subject):
Federal Rulemaking Website: Go to http://www.regulations.gov and search for Docket ID NRC-2016-0082. Address
questions about NRC dockets to Carol Gallagher; telephone: 301-415-
3463; email: [email protected]. For technical questions contact
the individuals listed in the FOR FURTHER INFORMATION CONTACT section
of this document.
Email comments to: [email protected]. If you do
not receive an automatic email reply confirming receipt, then contact
us at 301-415-1677.
Fax comments to: Secretary, U.S. Nuclear Regulatory
Commission at 301-415-1101.
Mail comments to: Secretary, U.S. Nuclear Regulatory
Commission, Washington, DC 20555-0001, ATTN: Rulemakings and
Adjudications Staff.
Hand deliver comments to: 11555 Rockville Pike, Rockville,
Maryland 20852, between 7:30 a.m. and 4:15 p.m. (Eastern Time) Federal
workdays; telephone: 301-415-1677.
For additional direction on obtaining information and submitting
comments, see ``Obtaining Information and Submitting Comments'' in the
SUPPLEMENTARY INFORMATION section of this document.
FOR FURTHER INFORMATION CONTACT: James G. O'Driscoll, Office of Nuclear
Material Safety and Safeguards, telephone: 301-415-1325, email:
James.O'[email protected]; or Keith Hoffman, Office of Nuclear Reactor
Regulation, telephone: 301-415-1294, email: [email protected]. Both
are staff of the U.S. Nuclear Regulatory Commission, Washington, DC
20555-0001.
SUPPLEMENTARY INFORMATION:
Executive Summary
A. Need for the Regulatory Action
The NRC is proposing to amend its regulations to incorporate by
reference the 2015 and 2017 Editions of the ASME BPV Code and the 2015
and 2017 Editions of the ASME OM Code, respectively, for nuclear power
plants. The NRC is also proposing to incorporate by reference two ASME
code cases.
This proposed rule is the latest in a series of rulemakings to
amend the NRC's regulations to incorporate by reference revised and
updated ASME Codes for nuclear power plants. The ASME periodically
revises and updates its codes for nuclear power plants by issuing new
editions, and this rulemaking is in accordance with the NRC's policy to
update the regulations to incorporate those new editions into the NRC's
regulations. The incorporation of the new editions will maintain the
safety of nuclear power plants, make NRC activities more effective and
efficient, and allow nuclear power plant licensees and applicants to
take advantage of the latest ASME Codes. The ASME is a voluntary
consensus standards organization, and the ASME Codes are voluntary
consensus standards. The NRC's use of the ASME Codes is consistent with
applicable requirements of the National Technology Transfer and
Advancement Act (NTTAA). Additional discussion of voluntary consensus
standards and the NRC's compliance with the NTTAA is set forth in
Section VIII of this document, ``Voluntary Consensus Standards.''
B. Major Provisions
Major provisions of this proposed rule include:
Incorporation by reference of ASME Codes (2015 and 2017
Editions of the BPV Code and the OM Code) into NRC regulations and
delineation of NRC requirements for the use of these codes, including
conditions.
Incorporation by reference of two revised ASME Code Cases
and delineation of NRC requirements for the use of these code cases,
including conditions.
Incorporation by reference of Electric Power Research
Institute (EPRI), Materials Reliability Project (MRP) Topical Report,
``Materials Reliability Program: Topical Report for Primary Water
Stress Corrosion Cracking Mitigation by Surface Stress Improvement''
(MRP-335, Revision 3-A), which provides requirements for the mitigation
of primary water stress corrosion cracking (PWSCC) on Reactor Vessel
Head penetrations and Dissimilar Metal Butt Welds.
C. Costs and Benefits
The NRC prepared a draft regulatory analysis to determine the
expected costs and benefits of this proposed rule. The regulatory
analysis identifies costs and benefits in both a quantitative fashion
as well as in a qualitative fashion.
The analysis concludes that this proposed rule would result in a
net quantitative averted cost to the industry and the NRC. This
proposed rule, relative to the regulatory baseline, would result in a
net averted cost for industry of $3.64 million based on a 7 percent net
present value (NPV) and $4.17 million based on a 3 percent NPV. The
estimated incremental industry averted cost per reactor unit ranges
from $37,900 based on a 7 percent NPV to $43,300 based on a 3 percent
NPV. The NRC benefits from the proposed rulemaking alternative because
of the averted cost of not reviewing and approving Code alternative
requests on a plant-specific basis under Sec. 50.55a(z) of title 10 of
the Code of Federal Regulations (10 CFR). The NRC net benefit ranges
from $2.81 million based on a 7 percent NPV to $3.49 million based on a
3 percent NPV.
Qualitative factors that were considered include regulatory
stability and predictability, regulatory efficiency, and consistency
with the NTTAA. Table 38 in the draft regulatory analysis includes a
discussion of the costs and benefits that were considered
qualitatively. If the results of the regulatory analysis were based
solely on quantified costs and benefits, then the
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regulatory analysis would show that the rulemaking is justified because
the total quantified benefits of the proposed regulatory action do not
equal or exceed the costs of the proposed action. Further, if the
qualitative benefits (including the safety benefit, cost savings, and
other non-quantified benefits) are considered together with the
quantified benefits, then the benefits outweigh the identified
quantitative and qualitative impacts.
With respect to regulatory stability and predictability, the NRC
has had a decades-long practice of approving and/or mandating the use
of certain parts of editions and addenda of these ASME Codes in Sec.
50.55a through the rulemaking process of ``incorporation by
reference.'' Retaining the practice of approving and/or mandating the
ASME Codes continues the regulatory stability and predictability
provided by the current practice. Retaining the practice also assures
consistency across the industry, and provides assurance to the industry
and the public that the NRC will continue to support the use of the
most updated and technically sound techniques developed by the ASME to
provide adequate protection to the public. In this regard, the ASME
Codes are voluntary consensus standards developed by participants with
broad and varied interests and have undergone extensive external review
before being reviewed by the NRC. Finally, the NRC's use of the ASME
Codes is consistent with the NTTAA, which directs Federal agencies to
adopt voluntary consensus standards instead of developing ``government-
unique'' (i.e., Federal agency-developed) standards, unless
inconsistent with applicable law or otherwise impractical.
For more information, please see the draft regulatory analysis
(Accession No. ML18150A267 in the NRC's Agencywide Documents Access and
Management System (ADAMS)).
Table of Contents
I. Obtaining Information and Submitting Comments
A. Obtaining Information
B. Submitting Comments
II. Background
III. Discussion
A. ASME BPV Code, Section III
B. ASME BPV Code, Section XI
C. ASME OM Code
IV. Section-by-Section Analysis
V. Generic Aging Lessons Learned Report
VI. Specific Request for Comment
VII. Plain Writing
VIII. Voluntary Consensus Standards
IX. Incorporation by Reference--Reasonable Availability to
Interested Parties
X. Environmental Assessment and Final Finding of No Significant
Environmental Impact
XI. Paperwork Reduction Act Statement
XII. Regulatory Analysis
XIII. Backfitting and Issue Finality
XIV. Regulatory Flexibility Certification
XV. Availability of Documents
I. Obtaining Information and Submitting Comments
A. Obtaining Information
Please refer to Docket ID NRC-2016-0082 when contacting the NRC
about the availability of information for this proposed rule. You may
obtain information related to this proposed rule by any of the
following methods:
Federal Rulemaking Website: Go to http://www.regulations.gov and search for Docket ID NRC-2016-0082.
NRC's Agencywide Documents Access and Management System
(ADAMS): You may obtain publicly-available documents online in the
ADAMS Public Documents collection at http://www.nrc.gov/reading-rm/adams.html. To begin the search, select ``ADAMS Public Documents'' and
then select ``Begin Web-based ADAMS Search.'' For problems with ADAMS,
please contact the NRC's Public Document Room (PDR) reference staff at
1-800-397-4209, 301-415-4737, or by email to [email protected]. For
the convenience of the reader, instructions about obtaining materials
referenced in this document are provided in the ``Availability of
Documents'' section.
NRC's PDR: You may examine and purchase copies of public
documents at the NRC's PDR, Room O1-F21, One White Flint North, 11555
Rockville Pike, Rockville, Maryland 20852.
B. Submitting Comments
Please include Docket ID NRC-2016-0082 in your comment submission.
The NRC cautions you not to include identifying or contact
information that you do not want to be publicly disclosed in your
comment submission. The NRC will post all comment submissions at http://www.regulations.gov as well as enter the comment submissions into
ADAMS. The NRC does not routinely edit comment submissions to remove
identifying or contact information.
If you are requesting or aggregating comments from other persons
for submission to the NRC, then you should inform those persons not to
include identifying or contact information that they do not want to be
publicly disclosed in their comment submission. Your request should
state that the NRC does not routinely edit comment submissions to
remove such information before making the comment submissions available
to the public or entering the comment into ADAMS.
II. Background
The ASME develops and publishes the ASME BPV Code, which contains
requirements for the design, construction, and inservice inspection
(ISI) of nuclear power plant components; and the ASME OM Code,\1\ which
contains requirements for inservice testing (IST) of nuclear power
plant components. Until 2012, the ASME issued new editions of the ASME
BPV Code every 3 years and addenda to the editions annually, except in
years when a new edition was issued. Similarly, the ASME periodically
published new editions and addenda of the ASME OM Code. Starting in
2012, the ASME decided to issue editions of its BPV and OM Codes (no
addenda) every 2 years with the BPV Code to be issued on the odd years
(e.g., 2013, 2015, etc.) and the OM Code to be issued on the even years
\2\ (e.g., 2012, 2014, etc.). The new editions and addenda typically
revise provisions of the Codes to broaden their applicability, add
specific elements to current provisions, delete specific provisions,
and/or clarify them to narrow the applicability of the provision. The
revisions to the editions and addenda of the Codes do not significantly
change Code philosophy or approach.
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\1\ The editions and addenda of the ASME Code for Operation and
Maintenance of Nuclear Power Plants have had different titles from
2005 to 2017 and are referred to collectively in this rule as the
``OM Code.''
\2\ The 2014 Edition of the ASME OM Code was delayed and was
designated the 2015 Edition. Similarly, the 2016 Edition of the OM
Code was delayed and was designated the 2017 Edition.
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The NRC's practice is to establish requirements for the design,
construction, operation, ISI (examination), and IST of nuclear power
plants by approving the use of editions and addenda of the ASME BPV and
OM Codes (ASME Codes) in Sec. 50.55a. The NRC approves or mandates the
use of certain parts of editions and addenda of these ASME Codes in
Sec. 50.55a through the rulemaking process of ``incorporation by
reference.'' Upon incorporation by reference of the ASME Codes into
Sec. 50.55a, the provisions of the ASME Codes are legally-binding NRC
requirements as delineated in Sec. 50.55a, and subject to the
conditions on certain specific ASME Codes' provisions that are set
forth in Sec. 50.55a. The editions and addenda of the ASME BPV and OM
Codes were last incorporated by reference into the NRC's regulations in
a final rule dated July 18, 2017 (82 FR 32934).
The ASME Codes are consensus standards developed by participants
with broad and varied interests
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(including the NRC and licensees of nuclear power plants). The ASME's
adoption of new editions of, and addenda to, the ASME Codes does not
mean that there is unanimity on every provision in the ASME Codes.
There may be disagreement among the technical experts, including the
NRC's representatives on the ASME Code committees and subcommittees,
regarding the acceptability or desirability of a particular Code
provision included in an ASME-approved Code edition or addenda. If the
NRC believes that there is a significant technical or regulatory
concern with a provision in an ASME-approved Code edition or addenda
being considered for incorporation by reference, then the NRC
conditions the use of that provision when it incorporates by reference
that ASME Code edition or addenda. In some instances, the condition
increases the level of safety afforded by the ASME Code provision, or
addresses a regulatory issue not considered by the ASME. In other
instances, where research data or experience has shown that certain
Code provisions are unnecessarily conservative, the condition may
provide that the Code provision need not be complied with in some or
all respects. The NRC's conditions are included in Sec. 50.55a,
typically in paragraph (b) of that section. In a Staff Requirements
Memorandum (SRM) dated September 10, 1999, the Commission indicated
that NRC rulemakings adopting (incorporating by reference) a voluntary
consensus standard must identify and justify each part of the standard
that is not adopted. For this rulemaking, the provisions of the 2015
and 2017 Editions of Section III, Division 1; and the 2015 and 2017
Editions of Section XI, Division 1, of the ASME BPV Code; and the 2015
and 2017 Editions of the ASME OM Code that the NRC is not adopting, or
is only partially adopting, are identified in the Discussion,
Regulatory Analysis, and Backfitting and Issue Finality sections of
this document. The provisions of those specific editions and code cases
that are the subject of this proposed rule that the NRC finds to be
conditionally acceptable, together with the applicable conditions, are
also identified in the Discussion, Regulatory Analysis, and Backfitting
and Issue Finality sections of this document.
The ASME Codes are voluntary consensus standards, and the NRC's
incorporation by reference of these Codes is consistent with applicable
requirements of the NTTAA. Additional discussion on the NRC's
compliance with the NTTAA is set forth in Section VIII of this
document, ``Voluntary Consensus Standards.''
III. Discussion
The NRC follows a three-step process to determine acceptability of
new provisions in new editions to the Codes and the need for conditions
on the uses of these Codes. This process was employed in the review of
the Codes that are the subjects of this proposed rule. First, the NRC
staff actively participates with other ASME committee members with full
involvement in discussions and technical debates in the development of
new and revised Codes. This includes a technical justification of each
new or revised Code. Second, the NRC's committee representatives
discuss the Codes and technical justifications with other cognizant NRC
staff to ensure an adequate technical review. Third, the NRC position
on each Code is reviewed and approved by NRC management as part of this
proposed rule amending Sec. 50.55a to incorporate by reference new
editions of the ASME Codes and conditions on their use. This regulatory
process, when considered together with the ASME's own process for
developing and approving the ASME Codes, provides reasonable assurance
that the NRC approves for use only those new and revised Code edition
and addenda, with conditions as necessary, that provide reasonable
assurance of adequate protection to the public health and safety, and
that do not have significant adverse impacts on the environment.
The NRC reviewed changes to the Codes in the editions identified in
this proposed rule. The NRC concluded, in accordance with the process
for review of changes to the Codes, that these editions of the Codes,
are technically adequate, consistent with current NRC regulations, and
approved for use with the specified conditions upon the conclusion of
the rulemaking process.
The NRC is proposing to amend its regulations to incorporate by
reference:
The 2015 and 2017 Editions to the ASME BPV Code, Section
III, Division 1 and Section XI, Division 1, with conditions on their
use.
The 2015 and 2017 Editions to Division 1 of the ASME OM
Code, with conditions on their use.
ASME BPV Code Case N-729-6, ``Alternative Examination
Requirements for PWR [Pressurized Water Reactor] Reactor Vessel Upper
Heads With Nozzles Having Pressure-Retaining Partial-Penetration Welds
Section XI, Division 1,'' ASME approval date: March 3, 2016, with
conditions on its use.
ASME BPV Code Case N-770-5, ``Alternative Examination
Requirements and Acceptance Standards for Class 1 PWR Piping and Vessel
Nozzle Butt Welds Fabricated with UNS N06082 or UNS W86182 Weld Filler
Material With or Without Application of Listed Mitigation Activities,
Section XI, Division 1,'' ASME approval date: November 7, 2016, with
conditions on its use.
``Materials Reliability Program: Topical Report for
Primary Water Stress Corrosion Cracking Mitigation by Surface Stress
Improvement'' (MRP-335, Revision 3-A), EPRI approval date: November
2016.
The current regulations in Sec. 50.55a(a)(1)(i) incorporate by
reference ASME BPV Code, Section III, 1963 Edition through the 1970
Winter Addenda; and the 1971 Edition (Division 1) through the 2013
Edition (Division 1), subject to the conditions identified in current
Sec. 50.55a(b)(1)(i) through (b)(1)(ix). This proposed rule would
revise Sec. 50.55a(a)(1)(i) to incorporate by reference the 2015 and
2017 Editions (Division 1) of the ASME BPV Code, Section III.
The current regulations in Sec. 50.55a(a)(1)(ii) incorporate by
reference ASME BPV Code, Section XI, 1970 Edition through the 1976
Winter Addenda; and the 1977 Edition (Division 1) through the 2013
Edition (Division 1), subject to the conditions identified in current
Sec. 50.55a(b)(2)(i) through (b)(2)(xxix). This proposed rule would
revise Sec. 50.55a(a)(1)(ii) to remove exclusions from the
incorporation by reference of specific paragraphs of the 2011a Addenda
and the 2013 Edition of ASME BPV Code, Section XI, as explained in this
document. This proposed rule would also revise Sec. 50.55a(a)(1)(ii)
to incorporate by reference 2015 and 2017 Editions (Division 1) of the
ASME BPV Code, Section XI. It would also clarify the wording and add,
remove, or revise some of the conditions as explained in this document.
The current regulations in Sec. 50.55a(a)(1)(iv) incorporate by
reference ASME OM Code, 1995 Edition through the 2012 Edition, subject
to the conditions currently identified in Sec. 50.55a(b)(3)(i) through
(b)(3)(xi). This proposed rule would revise Sec. 50.55a(a)(1)(iv) to
incorporate by reference the 2015 and 2017 Editions of Division 1 of
the ASME OM Code. As a result, the NRC regulations would incorporate by
reference in Sec. 50.55a the 1995 Edition through the 2017 Edition of
the ASME OM Code. In the
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introduction discussion of its Codes, ASME specifies that errata to
those Codes may be posted on the ASME website under the Committee Pages
to provide corrections to incorrectly published items, or to correct
typographical or grammatical errors in those Codes. ASME notes that an
option is available to automatically receive an email notification when
errata are posted to a Code. Users of the ASME BPV Code and ASME OM
Code should be aware of errata when implementing the specific
provisions of those Codes.
The proposed regulations in Sec. 50.55a (a)(4) would include the
Electric Power Research Institute, Materials Reliability Program, 3420
Hillview Avenue, Palo Alto, CA 94304-1338; telephone: 1-650-855-200;
http://www.epri.com, as a new source of documentation to be
incorporated by reference in Sec. 50.55a.
Each of the proposed NRC conditions and the reasons for each
proposed condition are discussed in the following sections of this
document. The discussions are organized under the applicable ASME Code
and Section.
A. ASME BPV Code, Section III
10 CFR 50.55a(a)(1)(E) Rules for Construction of Nuclear Facility
Components--Division 1
The NRC proposes to revise Sec. 50.55a(a)(1)(i)(E) to incorporate
by reference the 2015 and 2017 Editions of the ASME BPV Code, Section
III, including Subsection NCA and Division 1 Subsections NB through NH
(for the 2015 Edition) and Subsections NB through NG (for the 2017
Edition) and Appendices. As stated in Sec. 50.55a(a)(1)(i), the
Nonmandatory Appendices are excluded and not incorporated by reference.
The Mandatory Appendices are incorporated by reference because they
include information necessary for Division 1. However, the Mandatory
Appendices also include material that pertains to other Divisions that
have not been reviewed and approved by the NRC. Although this
information is included in the sections and appendices being
incorporated by reference, the NRC notes that the use of Divisions
other than Division 1 has not been approved, nor are they required by
NRC regulations and, therefore, such information is not relevant to
current applicants and licensees. Therefore, this proposed rule would
clarify that current applicants and licensees may only use the sections
of the Mandatory Appendices that pertain to Division 1. The NRC is not
taking a position on the non-Division 1 information in the appendices
and is including it in the incorporation by reference only for
convenience.
10 CFR 50.55a(b)(1)(v) Section III Condition: Independence of
Inspection
The 1995 Edition through the 2009b Addenda of the 2007 Edition of
ASME BPV Code, Section III, Subsection NCA, endorsed the NQA-1-1994
Edition in NCA-4000, ``Quality Assurance.'' Paragraph (a) of NCA-
4134.10, ``Inspection,'' states, ``The provisions of NQA-1 Basic
Requirement 10 and Supplement 10S-1, shall apply, except for paragraph
3.1, and the requirements of Inservice Inspection.'' Paragraph 3.1,
``Reporting Independence,'' of Supplement 10S-1, of NQA-1, states,
``Inspection personnel shall not report directly to the immediate
supervisors who are responsible for performing the work being
inspected.'' In the 2010 Edition through the latest ASME BPV Code
Editions of NCA, the Code removed the paragraph 3.1 exception for
reporting independence.
Based on the above changes to the Code, the NRC is proposing to
revise the condition to reflect that this condition is applicable only
for the 1995 Edition through 2009b Addenda of the 2007 Edition, where
the NQA-1-1994 Edition is referenced.
10 CFR 50.55a(b)(1)(vi) Section III Condition: Subsection NH
The NRC proposes to revise this existing condition since Subsection
NH of Section III Division 1 no longer exists in the 2017 Edition of
ASME BPV Code, Section III Division 1. The change is to reflect that
Subsection NH existed from the 1995 Addenda through 2015 Edition of
Section III Division 1. In 2015, Subsection NH contents also were
included in Section III Division 5 Subpart B. In the 2017 Edition of
the ASME Code, Subsection NH was deleted from Division 1 of Section III
and became part of Division 5 of Section III. Division 5 of Section III
is not incorporated by reference in Sec. 50.55a. Therefore, the NRC
proposes to revise the condition to make it applicable to the 1995
Addenda through all Editions and addenda up to and including the 2013
Edition.
10 CFR 50.55a(b)(1)(x) Section III Condition: Visual Examination of
Bolts, Studs, and Nuts
The visual examination is one of the processes for acceptance of a
bolt, stud or nut to ensure its structural integrity and its ability to
perform its intended function. The 2015 Edition of the ASME Code
contains this requirement, however the 2017 Edition does not require
these visual examinations to be performed in accordance with NX-5100
and NX-5500. Therefore, the NRC proposes to add two conditions to
ensure adequate procedures remain and qualified personnel remain
capable of determining the structural integrity of these components.
10 CFR 50.55a(b)(1)(x) Section III Condition: Visual Examination of
Bolts, Studs, and Nuts, First Provision
The NRC is adding Sec. 50.55a(b)(1)(x) to condition the provisions
of NB-2582, NC-2582, ND-2582, NE-2582, NF-2582, NG-2582 in the 2017
Edition of Section III. The condition is that the visual examinations
are required to be performed in accordance with procedures qualified to
NB-5100, NC-5100, ND-5100, NE-5100, NF-5100, and NG-5100, and personnel
qualified to NB-5500, NC-5500, ND-5500, NE-5500, NF-5500, and NG-5500,
respectively. The 2015 Edition of the ASME Code contains this
requirement. The visual examination is one of the processes for
acceptance of the final product to ensure its structural integrity and
its ability to perform its intended function. The 2017 Edition does not
require these visual examinations to be performed in accordance with
NX-5100 and NX-5500. All other final examinations (MT, PT, UT and RT)
for acceptance of the final product in the 2017 Edition require the
procedures and personnel to be qualified to NX-5100 and NX-5500.
Therefore, the NRC proposes to add Sec. 50.55a(b)(1)(x)(A) to
condition the provisions of NB-2582, NC-2582, ND-2582, NE-2582, NF-
2582,and NG-2582 in the 2017 Edition of Section III to require that
procedures are qualified to NB-5100, NC-5100, ND-5100, NE-5100, NF-
5100, and NG-5100, and personnel are qualified to NB-5500, NC-5500, ND-
5500, NE-5500, NF-5500, and NG-5500, respectively, in order to ensure
adequate procedures and personnel remain capable of determining the
structural integrity of these components. This is particularly
important for small bolting, studs and nuts that only receive a visual
examination. As stated in NX-4123 of Section III, only inspections
performed in accordance with Article NX-4000 (e.g., marking,
dimensional measurement, fitting, alignment) are exempted from NX-5100
and NX-5500, and may be qualified in accordance with the Certificate
Holder's Quality Assurance Program.
[[Page 56160]]
10 CFR 50.55a(b)(1)(x) Section III Condition: Visual Examination of
Bolts, Studs, and Nuts, Second Provision
The 2017 Edition requires that the final surfaces of threads,
shanks, and the heads be visually examined against ASTM F788, for
bolting material, and ASTM F812, for nuts, for workmanship, finish, and
appearance. This examination is for acceptance of the final product to
ensure its structural integrity, especially for small bolting that only
receives a visual examination. However, performing an inspection for
workmanship or appearance to the bolting specification is not
necessarily sufficient to ensure the integrity of the bolts and nuts
for their intended function in a reactor. The visual examination in
Section III for bolting and nuts is intended to determine structural
integrity for its intended function, which may entail quality
requirements more stringent than the bolting specifications. As
specified in the 2015 Edition of Section III: ``discontinuities such as
laps, seams, or cracks that would be detrimental to the intended
service are unacceptable.''
Therefore, the NRC proposes to add Sec. 50.55a(b)(1)(x)(B) to
condition the provisions of NB-2582, NC-2582, ND-2582, NE-2582, NF-
2582, and NG-2582 in the 2017 Edition of Section III, to require use of
the acceptance criteria from NB-2582, NC-2582, ND-2582, NE-2582, NF-
2582, and NG-2582 in the 2015 Edition of Section III.
10 CFR 50.55a(b)(1)(xi) Section III Condition: Mandatory Appendix XXVI
The NRC proposes to add a new paragraph with conditions on the use
of ASME BPV Code, Section III, Appendix XXVI for installation of high
density polyethylene (HDPE) pressure piping. This Appendix is new in
the 2015 Edition of Section III, and electrofusion joining was added to
this Appendix in the 2017 Edition of Section III. The 2015 Edition of
Section III is the first time the ASME Code has provided rules for the
use of polyethylene piping. The NRC has determined that the conditions
that follow in Sec. 50.55a(b)(1)(xi)(A) through (E) are necessary in
order to utilize polyethylene piping in Class 3 safety-related
applications. The conditions in Sec. 50.55a(b)(1)(xi)(A) and (B)
pertain to butt fusion joints and apply to both the 2015 and 2017
Editions of Section III. The conditions in Sec. 50.55a(b)(1)(xi)(C)
through (E) pertain to electrofusion joints and apply only to the 2017
Edition of Section III.
Both NRC and industry-funded independent research programs have
shown that joint failure is the most likely cause of structural failure
in HDPE piping systems. Poorly manufactured joints are susceptible to
early structural failure driven by ``slow crack growth,'' a form of
subcritical creep crack growth that is active in HDPE. The 5 provisions
below are aimed at ensuring the highest quality for joints in HDPE
systems and reducing the risk of poor joint fabrication. These
provisions minimize the risk of joint structural failure and the
resulting potential loss of system safety function.
10 CFR 50.55a(b)(1)(xi)(A) Mandatory Appendix XXVI: First Provision
The NRC proposes to add a new paragraph (b)(1)(xi)(A), which
specifies the essential variables to be used in qualifying fusing
procedures for butt fusion joints in polyethylene piping installed in
accordance with ASME Section III, Mandatory Appendix XXVI. The NRC does
not endorse the use of a standardized fusing procedure specification. A
fusion procedure specification will need to be generated for each butt
fusion joint with the essential variables, as listed. The same
variables will be listed for operator performance qualifications.
Per ASME BPV Code Section IX, QF-252, essential variables are those
that will affect the mechanical properties of the fused joint, if
changed, and require requalification of the Fusing Procedure
Specification (FPS), Standard Fusing Procedure Specification (SFPS), or
Manufacturer Qualified Electrofusion Procedure Specification (MEFPS)
when any change exceeds the specified limits of the values recorded in
the FPS for that variable. Fourteen essential variables for HDPE butt
fusion joints for nuclear applications have been identified by NRC and
industry experts through extensive research and field experience. Ten
of these essential variables are the same as those identified in ASME
BPV Code, Section IX, Table QF-254, which applies to all HDPE butt
fusions and is not limited to nuclear applications. The other 4
variables deemed essential by the NRC are: Diameter, cross-sectional
area, ambient temperature, and fusing machine carriage model. These 4
additional variables are recognized by industry experts as being
essential for butt fusion joints in nuclear safety applications, and
have been included in a proposal to list essential variables for butt
fusion in the 2019 Edition of ASME BPV Code, Section III, Mandatory
Appendix XXVI.
For nuclear applications, the use of HDPE is governed by ASME BPV
Code, Section III, Mandatory Appendix XXVI. The NRC has determined that
to ensure butt fusion joint quality is adequate for nuclear safety
applications, referencing ASME BPV Code, Section IX in ASME BPV Code,
Section III, Mandatory Appendix XXVI is not sufficient, because ASME
BPV Code, Section IX is not incorporated into NRC regulations.
Therefore, the NRC is including the essential variables for HDPE butt
fusion as a condition on the use of ASME BPV Code Section III,
Mandatory Appendix XXVI. This provision addresses the fact that the
essential variables for HDPE butt fusion are not listed in the 2015 and
2017 Editions of ASME BPV Code, Section III, Mandatory Appendix XXVI.
Proposals to incorporate these essential variables for butt fusion in
the 2019 Edition of the Code have already been drafted and circulated
within the ASME Code Committees. In the meantime, the NRC is proposing
to add this provision to ensure butt fusion joint quality for nuclear
safety applications.
10 CFR 50.55a(b)(1)(xi)(B) Mandatory Appendix XXVI: Second Provision
The NRC proposes to add a new paragraph (b)(1)(xi)(B), which will
require both bend tests and high speed tensile impact testing (HSTIT)
to qualify fusing procedures for joints in polyethylene piping
installed in accordance with ASME BPV Code, Section III, Mandatory
Appendix XXVI. The NRC requires both bend tests and HSTIT to qualify
the fusion procedures. There is data that suggests that HSTIT may not
distinguish between an acceptable and unacceptable HDPE butt fusion
joint and, therefore, should not be considered as a stand-alone test.
The NRC has performed limited confirmatory research on the ability
of short-term mechanical tests to predict the in-service behavior of
HDPE butt fusion joints. Based on this research as well as research
results from The Welding Institute in the UK, the NRC lacks conclusive
evidence that either of the two tests proposed in XXVI-4342(d) and
XXVI-4342(e) is always a reliable predictor of joint quality. As a
result, the NRC has determined that the combination of both test
results provides increased and sufficient indication of butt fusion
joint quality. Consequently, the NRC is proposing to add a condition
that requires both tests specified in in XXVI-4342(d) and XXVI-4342(e)
to be performed as part of performance qualification tests, instead of
only one or the other.
10 CFR 50.55a(b)(1)(xi)(C) Mandatory Appendix XXVI: Third Provision
The NRC is proposing to add a new paragraph (b)(1)(xi)(C), which
specifies the essential variables to be used in
[[Page 56161]]
qualifying fusing procedures for electrofusion of fusion joints in
polyethylene piping that is to be installed in accordance with ASME BPV
Code, Section III, Mandatory Appendix XXVI. The NRC does not endorse
the use of a standardized fusing procedure specification. A fusion
procedure specification will need to be generated for each
electrofusion joint with the essential variables as listed. The same
variables will be listed for operator performance qualifications.
Per ASME BPV Code, Section IX, QF-252: ``Essential variables are
those that will affect the mechanical properties of the fused joint, if
changed, and require requalification of the FPS, SFPS, or MEFPS when
any change exceeds the specified limits of the values recorded in the
FPS for that variable.'' Sixteen essential variables for HDPE
electrofusion for nuclear applications have been identified by NRC and
industry experts through extensive research and field experience.
Twelve of these essential variables are the same as those identified in
ASME BPV Code, Section IX Table QF-255, which applies to all HDPE
electrofusion and is not limited to nuclear applications. The other 4
variables deemed essential by the NRC are: fitting polyethylene
material, pipe wall thickness, power supply, and processor. These 4
additional variables are recognized by industry experts as being
essential for electrofusion joints in nuclear safety applications, and
have been included in a proposal to list essential variables for
electrofusion in the 2019 Edition of ASME BPV Code, Section III
Mandatory Appendix XXVI.
For nuclear applications, the use of HDPE is governed by ASME BPV
Code, Section III Mandatory Appendix XXVI. The NRC has determined that,
to ensure electrofusion joint quality is adequate for nuclear safety
applications, referencing ASME BPV Code, Section IX in ASME BPV Code,
Section III Mandatory Appendix XXVI is not sufficient, because ASME BPV
Code, Section IX is not incorporated into NRC regulations. Therefore,
the NRC is including the essential variables for HDPE electrofusion as
a condition on the use of ASME Section III, Mandatory Appendix XXVI.
This provision addresses the fact that the essential variables for HDPE
electrofusion are not listed in the 2015 and 2017 Editions of ASME BPV
Code, Section III, Mandatory Appendix XXVI. Proposals to incorporate
these essential variables for electrofusion in the 2019 Edition of the
Code have already been drafted and circulated within the ASME Code
Committees. In the meantime, the NRC proposes to add this provision to
ensure electrofusion joint quality for nuclear safety applications.
10 CFR 50.55a(b)(1)(xi)(D) Mandatory Appendix XXVI: Fourth Provision
The NRC is proposing to add a new paragraph (b)(1)(xi)(D), which
will require both crush tests and electrofusion bend tests to qualify
fusing procedures for electrofusion joints in polyethylene piping
installed in accordance with the 2017 Edition of ASME BPV Code, Section
III, Mandatory Appendix XXVI. The NRC proposes to require both crush
tests and electrofusion bend tests to qualify the electrofusion
procedures. The operating experience data on electrofusion joints is
extremely limited and also indicates some failures. In order to ensure
structural integrity of electrofusion joints in safety related
applications, the NRC is proposing to require that both crush tests and
electrofusion bend tests be performed to demonstrate an acceptable HDPE
electrofusion joint test.
Furthermore, a demonstration that the system or repair will not
lose the ability to perform its safety function during its service life
must be provided for systems that use electrofusion joints. The NRC
lacks conclusive evidence regarding the ability of short-term
mechanical tests to predict the in-service behavior of HDPE
electrofusion joints in nuclear safety related applications. The NRC
considers that either of the 2 tests (crush test or electrofusion bend
test) proposed in XXVI-2332(a) and XXVI-2332(b), separately, may not be
a reliable predictor of electrofusion joint quality. As a result, the
NRC has determined that the combination of both test results provides
increased and sufficient indication of electrofusion joint quality.
Consequently, the NRC is proposing to add a condition that requires
that both tests (crush test and electrofusion bend test) specified in
in XXVI-2332(a) and XXVI-2332(b) be performed as part of performance
qualification tests, instead of only one or the other.
10 CFR 50.55a(b)(1)(xi)(E) Mandatory Appendix XXVI: Fifth Provision
The NRC is proposing to add a new paragraph (b)(1)(xi)(E), which
prohibits the use of electrofusion saddle fittings and electrofusion
saddle joints. The NRC believes that the failure of electrofusion
saddle joints can result in a gross structural rupture leading to loss
of safety function for the system where such a joint is present.
Consequently, only full 360[deg] seamless sleeve electrofusion
couplings (Electrofusion coupling, as shown in Table XXVI-3311-1 of the
ASME BPV Code, Section III, 2017 Edition) and full 360[deg]
electrofusion socket joints (as shown in the top image in Figure XXVI-
4110-2 of ASME BPV Code, Section III, 2017 Edition) are permitted.
Very limited information and operational experience is available
for electrofusion joints in nuclear safety applications, and some
Department of Energy operational experience indicates that failures
have occurred in electrofusion joints. The NRC has determined that the
failure of a saddle type electrofusion joint could result in structural
separation of the electrofusion saddle coupling from the HDPE pipe it
is attached to, resulting in a potential loss of flow and loss of
safety function in the system. As a result, the NRC is proposing to add
a condition that will only allow full 360[deg] seamless sleeve type
electrofusion couplings, attached with a socket type electrofusion
joint. The failure of such a joint is far less likely to result in a
total loss of flow and safety function. For full 360[deg] seamless
sleeve type electrofusion couplings attached with a socket type
electrofusion joint, full separation of the coupling from the pipe is
highly unlikely.
10 CFR 50.55a(b)(1)(xii) Section III Condition: Certifying Engineer
The NRC is proposing to add a new condition Sec. 50.55a(b)(1)(xii)
Section III Condition: Certifying Engineer. In the 2017 Edition of ASME
BPV Code, Section III, Subsection NCA, the following Subsections were
updated to replace the term ``registered professional engineer,'' with
term ``certifying engineer'' to be consistent with ASME BPV Code
Section III Mandatory Appendix XXIII.
NCA-3255 ``Certification of the Design Specifications''
NCA-3360 ``Certification of the Construction Specification,
Design Drawings, and Design Report''
NCA-3551.1 ``Design Report''
NCA-3551.2 ``Load Capacity Data Sheet''
NCA-3551.3 ``Certifying Design Report Summary'' and
NCA-3555 ``Certification of Design Report''
Table NCA-4134.17-2, ``Nonpermanent Quality Assurance
Records''
NCA-5125, ``Duties of Authorized Nuclear Inspector
Supervisors''
NCA-9200, ``Definitions''
The NRC reviewed these changes and has determined that the use of a
certifying engineer in lieu of a registered professional engineer is
only applicable
[[Page 56162]]
for non-U.S. nuclear facilities. Therefore, the term ``certifying
engineer'' is not applicable to U.S. nuclear facilities regulated by
the NRC. As a result, the NRC is proposing to add a new condition to
Sec. 50.55a (b)(1), that would not allow applicants and licensees to
use a certifying engineer in lieu of a registered professional engineer
for code-related activities that are applicable to U.S. nuclear
facilities regulated by the NRC.
B. ASME BPV Code, Section XI
10 CFR 50.55a(b)(2) Conditions on ASME BPV Code, Section XI
The NRC proposes to amend the regulations in Sec. 50.55a(b)(2) to
incorporate by reference the 2015 and the 2017 Editions (Division 1) of
the ASME BPV Code, Section XI. The current regulations in Sec.
50.55a(b)(2) incorporate by reference ASME BPV Code, Section XI, 1970
Edition through the 1976 Winter Addenda; and the 1977 Edition (Division
1) through the 2013 Edition (Division 1), subject to the conditions
identified in current Sec. 50.55a(b)(2)(i) through (b)(2)(xxix). The
proposed amendment would revise the introductory text to Sec.
50.55a(b)(2) to incorporate by reference the 2015 Edition (Division 1)
and the 2017 Edition (Division 1) of the ASME BPV Code, Section XI,
clarify the wording, and revise or provide some additional conditions,
as explained in this document.
10 CFR 50.55a(b)(2)(vi) Effective Edition and Addenda of Subsection IWE
and Subsection IWL
The NRC proposes to remove existing condition Sec.
50.55a(b)(2)(vi). A final rule was published in the Federal Register
(61 FR 41303) on August 8, 1996, which incorporated by reference the
ASME BPV Code, Section XI, Subsection IWE and Subsection IWL for the
first time. The associated statements of consideration for that rule
identified the 1992 Edition with 1992 Addenda of Subsection IWE and
Subsection IWL as the earliest version that the NRC found acceptable. A
subsequent rule published on September 22, 1999 (64 FR 51370), included
the 1995 Edition with the 1996 Addenda as an acceptable edition of the
ASME BPV Code. The statements of considerations for a later rule
published on September 26, 2002 (67 FR 60520), noted that the 1992
Edition with the 1992 Addenda, or the 1995 Edition with the 1996
Addenda of Subsection IWE and IWL must be used when implementing the
initial 120-month interval for the ISI of Class MC and Class CC
components, and that successive 120-month interval updates must be
implemented in accordance with Sec. 50.55a(g)(4)(ii).
This requirement was in place to expedite the initial containment
examinations in accordance with Subsections IWE and IWL, which were
required to be completed during the 5-year period from September 6,
1996, to September 9, 2001. Now that there is an existing framework in
place for containment examinations in accordance with Subsections IWE
and IWL, there is no need for a condition specific to the initial
examination interval. The examinations conducted during the initial
interval can be conducted in accordance with Sec. 50.55a(g)(4).
10 CFR 50.55a(b)(2)(vii): Section XI Condition: Section XI References
to OM Part 4, OM Part 6, and OM Part 10 (Table IWA-1600-1).
The NRC proposes to remove the condition found in Sec.
50.55a(b)(2)(vii) of the current regulations. This paragraph describes
the editions and addenda of the ASME OM Code to be used with the
Section XI references to OM Part 4, OM Part 6, and OM Part 10 in Table
IWA-1600-1 of Section XI. The condition is applicable to the ASME BPV
Code, Section XI, Division 1, 1987 Addenda, 1988 Addenda, or 1989
Edition. Paragraph (g)(4)(ii) requires that a licensee's successive
120-month inspection intervals comply with the requirements of the
latest edition and addenda of the Code incorporated by reference in
Sec. 50.55a(b)(2). Because licensees are no longer using these older
editions and addenda of the Code referenced in this paragraph, this
condition can be removed.
10 CFR 50.55a(b)(2)(ix) Metal Containment Examinations
The NRC proposes to revise Sec. 50.55a(b)(2)(ix), to require
compliance with new condition Sec. 50.55a(b)(2)(ix)(K). The proposed
condition will ensure containment leak-chase channel systems are
properly inspected in accordance with the applicable requirements. The
NRC specifies the application of this condition to all editions and
addenda of Section XI, Subsection IWE, of the ASME BPV Code, prior to
the 2017 Edition, that are incorporated by reference in paragraph (b)
of Sec. 50.55a.
10 CFR 50.55a(b)(2)(ix)(K) Metal Containment Examinations
The NRC proposes to add Sec. 50.55a(b)(2)(ix)(K) to ensure
containment leak-chase channel systems are properly inspected.
Regulations in Sec. 50.55a(g), ``Inservice Inspection
Requirements,'' require that licensees implement the inservice
inspection program for pressure retaining components and their integral
attachments of metal containments and metallic liners of concrete
containments in accordance with Subsection IWE of Section XI of the
applicable edition and addenda of the ASME Code, incorporated by
reference in paragraph (b) of Sec. 50.55a and subject to the
applicable conditions in paragraph (b)(2)(ix). The regulatory condition
in Sec. 50.55a(b)(2)(ix)(A) or equivalent provision in Subsection IWE
of the ASME Code (2006 and later editions and addenda only) requires
that licensees shall evaluate the acceptability of inaccessible areas
when conditions exist in accessible areas that could indicate the
presence of, or result in, degradation to such inaccessible areas.
The containment floor weld leak-chase channel system forms a metal-
to-metal interface with the containment shell or liner, the test
connection end of which is at the containment floor level. Therefore,
the leak-chase system provides a pathway for potential intrusion of
moisture that could cause corrosion degradation of inaccessible
embedded areas of the pressure-retaining boundary of the basemat
containment shell or liner within it. In addition to protecting the
test connection, the cover plates and plugs and accessible components
of the leak-chase system within the access box are also intended to
prevent intrusion of moisture into the access box and into the
inaccessible areas of the shell/liner within the leak-chase channels,
thereby protecting the shell and liner from potential corrosion
degradation that could affect leak-tightness.
The containment ISI program required by Sec. 50.55a to be
implemented in accordance with Subsection IWE, of the ASME Code,
Section XI, subject to regulatory conditions, requires special
consideration of areas susceptible to accelerated corrosion degradation
and aging, and barriers intended to prevent intrusion of moisture and
water accumulation against inaccessible areas of the containment
pressure-retaining metallic shell or liner. The containment floor weld
leak-chase channel system is one such area subject to accelerated
degradation and aging if moisture intrusion and water accumulation is
allowed on the embedded shell and liner within it. Therefore, the leak-
chase channel system is subject to the inservice inspection
requirements of Sec. 50.55a(g)(4).
The NRC Information Notice (IN) 2014-07, ``Degradation of Leak-
Chase
[[Page 56163]]
Channel Systems for Floor Welds of Metal Containment Shell and Concrete
Containment Metallic Liner,'' (ADAMS Accession No. ML14070A114)
discusses examples of licensees that did not conduct the required
inservice inspections. The IN also summarizes the NRC's basis for
including the leak-chase components within the scope of Subsection IWE,
of the ASME Code, Section XI, and how licensees could fulfill the
requirements. The NRC guidance explains that 100 percent of the
accessible components of the leak-chase system should be inspected
during each inspection period. There are three inspection periods in
one ten-year inspection interval.
After issuance of IN 2014-07, the NRC received feedback during a
public meeting between NRC and ASME management, held on August 22, 2014
(ADAMS Accession No. ML14245A003), noting that the IN guidance appeared
to be in conflict with ASME Section XI Interpretation XI-1-13-10. In
response to the comment during the public meeting, the NRC issued a
letter to ASME (ADAMS Accession No. ML14261A051), which stated that the
NRC found the provisions in the IN to be consistent with the
requirements in the ASME Code; and the NRC staff may consider adding a
condition to Sec. 50.55a to clarify the expectations. The ASME
responded to the NRC's letter (ADAMS Accession No. ML15106A627) and
noted that a condition in the regulations may be appropriate to clarify
the NRC's position.
Based on the operating experience summarized in IN 2014-07, and the
industry feedback, the NRC has determined that a new condition is
necessary in Sec. 50.55a(b)(2)(ix) to clarify the NRC's expectations
and to ensure steel containment shells and liners receive appropriate
examinations. In the 2017 Edition of the ASME Code, a provision was
added that clearly specifies the examination of leak-chase channels.
The provision requires 100 percent examination of the leak-chase
channel closures over a ten-year inspection interval, as opposed to 100
percent during each inspection period. Although the examination
frequency is relaxed compared to the NRC's position as identified in IN
2014-07, the NRC finds the provision in the 2017 Edition acceptable
because the examination includes provisions for scope expansion and
examinations of additional closures if degradation is identified within
an inspection period. The NRC chose to align the condition with the
acceptable provision in the latest approved edition of the ASME Code.
This proposed condition would be applicable to all editions and addenda
of the ASME Code prior to the 2017 Edition.
10 CFR 50.55a(b)(2)(xvii) Section XI Condition: Reconciliation of
Quality Requirements
The NRC proposes to remove the condition found in the current Sec.
50.55a(b)(2)(xvii). This paragraph describes requirements for
reconciliation of quality requirements when purchasing replacement
items. When licensees use the 1995 Addenda through 1998 Edition of ASME
BPV Code, Section XI, this condition required replacement items to be
purchased in accordance with the licensee's quality assurance program
description required by 10 CFR 50.34(b)(6)(ii), in addition to the
reconciliation provisions of IWA-4200. The NRC has accepted without
conditions the content of IWA-4200 in versions of the Code since the
1999 Addenda of Section XI. Paragraph 50.55a(g)(4)(ii) requires that
licensee's successive 120-month inspection intervals comply with the
requirements of the latest edition and addenda of the Code incorporated
by reference in Sec. 50.55a(b)(2). Subsequently, licensees are no
longer using these older editions and addenda of the Code referenced in
this paragraph therefore this condition can be removed. Section
50.55a(b)(2)(xvii) would be designated as [Reserved].
10 CFR 50.55a(b)(2)(xviii)(D) NDE Personnel Certification: Fourth
Provision
The NRC proposes to amend the condition found in Sec.
50.55a(b)(2)(xviii) to extend the applicability of the condition
through the latest edition incorporated by reference in paragraph
(a)(1)(ii) of this section of ASME BPV Code, Section XI. This current
condition prohibits those licensees which use ASME BPV Code, Section
XI, 2011 Addenda through the 2013 Edition from using Appendix VII,
Table VII-4110-1 and Appendix VIII, Subarticle VIII-2200. The condition
requires licensees and applicants using these versions of Section XI to
use the prerequisites for ultrasonic examination personnel
certifications in Appendix VII, Table VII-4110-1 and Appendix VIII,
Subarticle VIII-2200 in the 2010 Edition. This condition was added when
the 2010 through the 2013 Edition was incorporated by reference. When
ASME published the 2015 Edition and the 2017 Editions, Appendix VII,
Table VII-4110-1 and Appendix VIII, Subarticle VIII-2200 of ASME BPV
Code, Section XI were not modified in a way that would make it possible
for the NRC to remove this condition. Therefore, the NRC is proposing
to retain this condition to apply to the latest edition incorporated by
reference in paragraph (a)(1)(ii) of Sec. 50.55a.
10 CFR 50.55a(b)(2)(xx)(B) Section XI Condition: System Leakage Tests:
Second Provision
The NRC proposes to amend the condition found in Sec.
50.55a(b)(2)(xx)(B) to clarify the NRC's expectations related to the
nondestructive examination (NDE) required when a system leakage test is
performed (in lieu of a hydrostatic test) following repair and
replacement activities performed by welding or brazing on a pressure
retaining boundary using the 2003 Addenda through the latest edition
and addenda of ASME BPV Code, Section XI incorporated by reference in
paragraph (a)(1)(ii) of Sec. 50.55a. Industry stakeholders have
expressed confusion on what was required by the current regulation with
regard to the Code edition/addenda that the requirements for NDE and
pressure testing were required to satisfy under this condition. The NRC
is proposing to modify the condition to clarify that the NDE method
(e.g., surface, volumetric, etc.) and acceptance criteria of the 1992
or later of ASME BPV Code, Section III shall be met. The actual
nondestructive examination and pressure testing may be performed using
procedures and personnel meeting the requirements of the licensee's/
applicant's current ISI code of record. This condition was first put in
place by the NRC in a final rule, which became effective October 10,
2008 (73 FR 52730). The NRC determined the condition was necessary
because the ASME BPV Code eliminated the requirement to perform the
Section III NDE when performing a system leakage test in lieu of a
hydrostatic test following repairs and replacement activities performed
by welding or brazing on a pressure retaining boundary in the 2003
Addenda of ASME BPV Code, Section XI. When ASME published the 2015
Edition and the 2017 Editions, IWA-4520 was not modified in a way that
would make it possible for the NRC to remove this condition. Therefore,
the NRC is proposing to retain this condition to apply to the latest
edition incorporated by reference in paragraph (a)(1)(ii) of Sec.
50.55a.
10 CFR 50.55a(b)(2)(xx)(C) Section XI Condition: System Leakage Tests:
Third Provision
The NRC proposes to add Sec. 50.55a(b)(2)(xx)(C) to provide 2
conditions for the use of the alternative
[[Page 56164]]
Boiling Water Reactor (BWR) Class 1 system leakage test described in
IWB-5210(c) and IWB-5221(d) of the 2017 Edition of ASME Section XI. The
first condition addresses a prohibition against the production of heat
through the use of a critical reactor core to raise the temperature of
the reactor coolant and pressurize the reactor coolant pressure
boundary (RCPB) (sometimes referred to as nuclear heat). The second
condition addresses the duration of the hold time when testing non-
insulated components to allow potential leakage to manifest itself
during the performance of system leakage tests.
The alternative BWR Class 1 system leakage test was intended to
address concerns that performing the ASME-required pressure test for
BWRs under shutdown conditions, (1) places the unit in a position of
significantly reduced margin, approaching the fracture toughness limits
defined in the Technical Specification Pressure-Temperature (P-T)
curves, and (2) requires abnormal plant conditions/alignments,
incurring additional risks and delays, while providing little added
benefit beyond tests, which could be performed at slightly reduced
pressures under normal plant conditions. However, due to restrictions
imposed by the pressure control systems, most BWRs cannot obtain
reactor pressure corresponding to 100 percent rated power during normal
startup operations at low power levels that would be conducive to
performing examinations for leakage. The alternative test would be
performed at slightly reduced pressures and normal plant conditions,
which the NRC finds will constitute an adequate leak examination and
would reduce the risk associated with abnormal plant conditions and
alignments.
However, the NRC has had a longstanding prohibition against the
production of heat through the use of a critical reactor core to raise
the temperature of the reactor coolant and pressurize the RCPB. A
letter dated February 2, 1990, from James M. Taylor, Executive Director
for Operations, NRC, to Messrs. Nicholas S. Reynolds and Daniel F.
Stenger, Nuclear Utility Backfitting and Reform Group (ADAMS Accession
No. ML14273A002), established the NRC's position with respect to use of
a critical reactor core to raise the temperature of the reactor coolant
and pressurize the RCPB. In summary, the NRC's position is that testing
under these conditions involves serious impediments to careful and
complete inspections and therefore creates inherent uncertainty with
regard to assuring the integrity of the RCPB. Further, the practice is
not consistent with basic defense-in-depth safety principles.
The NRC's position established in 1990, was reaffirmed in IN No.
98-13, ``Post-Refueling Outage Reactor Pressure Vessel Leakage Testing
Before Core Criticality,'' dated April 20, 1998. The IN was issued in
response to a licensee that had conducted an ASME BPV Code, Section XI,
leakage test of the reactor pressure vessel (RPV) and subsequently
discovered that it had violated 10 CFR part 50, appendix G, paragraph
IV.A.2.d. This regulation states that pressure tests and leak tests of
the reactor vessel that are required by Section XI of the ASME Code
must be completed before the core is critical. The IN references NRC
Inspection Report 50-254(265)-97027 (ADAMS Accession No. ML15216A276),
which documents that licensee personnel performing VT-2 examinations of
the drywell at one BWR plant covered 50 examination areas in 12
minutes, calling into question the adequacy of the VT-2 examinations.
The bases for the NRC's historical prohibition of pressure testing
with the core critical can be summarized as follows:
1. Nuclear operation of a plant should not commence before
completion of system hydrostatic and leakage testing to verify the
basic integrity of the RCPB, a principal defense-in-depth barrier to
the accidental release of fission products. In accordance with the
defense-in-depth safety precept, the nuclear power plant design
provides for multiple barriers to the accidental release of fission
products from the reactor.
2. Hydrotesting must be done essentially water solid (i.e., free of
pockets of air, steam or other gases) so that stored energy in the
reactor coolant is minimized during a hydrotest or leaktest.
3. The elevated reactor coolant temperatures, associated with
critical operation, result in a severely uncomfortable and difficult
working environment in plant spaces where the system leakage
inspections must be conducted. The greatly increased stored energy in
the reactor coolant, when the reactor is critical, increases the hazard
to personnel and equipment in the event of a leak. As a result, the
ability for plant workers to perform a comprehensive and careful
inspection becomes greatly diminished.
However, the NRC has determined that pressure testing with the core
critical is acceptable under the following conditions: When performed
after repairs of a limited scope; where only a few locations or a
limited area needs to be examined; and when ASME Code Section XI, Table
IWB-2500-1, Category B-P (the pressure test required once per cycle of
the entire RCPB) has been recently performed verifying the integrity of
the overall RCPB. The NRC also notes the alternative BWR Class 1 system
leakage test does not allow for the use of the alternative test
pressure following repairs/replacements on the RPV; therefore, it does
not violate 10 CFR part 50, appendix G. The NRC has determined that the
risk associated with nuclear heat at low power is comparable with the
risk to the plant, when the test is performed without nuclear heat
(with the core subcritical) during mid-cycle outages, when decay heat
must be managed. Performing the pressure test under shutdown conditions
at full operating pressure without nuclear heat requires securing
certain key pressure control, heat removal, and safety systems. It is
more difficult to control temperature and pressure when there is
significant production of decay heat (e.g., after a mid-cycle outage),
and may reduce the margin available to prevent exceeding the plant
pressure-temperature limits.
When the pressure test is conducted using nuclear heat, the scope
of repairs should be relatively small in order to minimize the
personnel safety risk and to avoid rushed examinations. The alternative
BWR Class 1 system leakage test does not place any restrictions on the
size or scope of the repairs for which the alternative may be used,
provided the alternative test pressure is not used to satisfy pressure
test requirements following repair/replacement activities on the
reactor vessel. It is impractical to specify a particular number of
welded or mechanical repairs that would constitute a ``limited scope.''
However, if the plant is still in a refueling outage and has already
performed the ASME Section XI Category B-P pressure test of the entire
RCPB, it is likely that subsequent repairs would be performed only on
an emergent basis, and would generally be of a limited scope.
Additionally, the overall integrity of the RCPB will have been recently
confirmed via the Category B-P test. For mid-cycle maintenance outages,
the first condition allows the use of nuclear heat to perform the test,
if the outage duration is 14 days or less. This would tend to limit the
scope of repairs, and also limit the use of the code case to outages
where there is a significant production of decay heat. Therefore, the
first condition on the alternative BWR Class 1 system leakage test
states: ``The use of nuclear heat to conduct the BWR Class 1 system
leakage test is prohibited (i.e.
[[Page 56165]]
the reactor must be in a non-critical state), except during refueling
outages in which the ASME Section XI Category B-P pressure test has
already been performed, or at the end of mid-cycle maintenance outages
fourteen (14) days or less in duration.''
With respect to the second condition and adequate pressure test
hold time, the technical analysis supporting the alternative BWR Class
1 system leakage test indicates that the lower test pressure provides
more than 90 percent of the flow that would result from the pressure
corresponding to 100 percent power. However, a reduced pressure means a
lower leakage rate, so additional time is required in order for there
to be sufficient leakage to be observed by inspection personnel.
Section XI, paragraph IWA-5213, ``Test Condition Holding Time,'' does
not require a holding time for Class 1 components, once test pressure
is obtained. To account for the reduced pressure, the alternative BWR
Class 1 system leakage test would require a 15-minute hold time for
non-insulated components. The NRC has determined that 15 minutes does
not allow for an adequate examination because it is not possible to
predict the entire range of scenarios or types of defects that could
result in leakage. Some types of defects could result in immediate
leakage, such as an improperly torqued bolted connection; however other
types of defects, such as weld defects or tight cracks, could present a
more torturous path for leakage and result in delayed leakage. Due to
the uncertainty in the amount of time required for leakage to occur to
an extent that it would be readily detectable by visual examination,
the NRC has determined that it is appropriate to conservatively specify
a longer hold time of 1 hour for non-insulated components. Therefore,
the second condition for the alternative BWR Class 1 system leakage
test would require a one hour hold time for non-insulated components.
10 CFR 50.55a(b)(2)(xxi) Section XI Condition: Table IWB-2500-1
Examination Requirements
The NRC proposes to remove the condition found in Sec.
50.55a(b)(2)(xxi)(A) to allow licensees to use the current editions of
ASME BPV Code, Section XI, Table IWB 2500-1, Examination Category B-D,
Full Penetration Welded Nozzles in Vessels, Items B3.40 and B3.60
(Inspection Program A) and Items B3.120 and B3.140 (Inspection Program
B). These inspection categories concern pressurizer and steam generator
nozzle inner radius section examinations. Previously, the condition
required licensees to use the 1998 Edition, which required examination
of the nozzle inner radius when using the 1999 Addenda through the
latest edition and addenda incorporated by reference in paragraph
(a)(1)(ii) of Sec. 50.55a. As these inspection requirements were
removed in the ASME BPV Code in 1999, this change would effectively
eliminate the requirement to examine the nozzle inner radii in steam
generators and pressurizers.
The requirements for examinations of inner nozzle radii in several
components were developed in the ASME BPV Code in reaction to the
discovery of thermal fatigue cracks in the inner-radius section of
boiling water reactor feedwater nozzles in the late 1970's and early
1980's. As described in NUREG/CR-7153, ``Expanded Materials Degradation
Assessment (EMDA),'' (ADAMS Accession Nos. ML14279A321, ML14279A461,
ML14279A349, ML14279A430, and ML14279A331), and NUREG-0619-Rev-1, ``BWR
Feedwater Nozzle and Control Rod Drive Return Line Nozzle Cracking:
Resolution of Generic Technical Activity A-10 (Technical Report),''
(ADAMS Accession No. ML031600712), the service-induced flaws that have
been observed are cracks at feedwater nozzles associated with mixing of
lower-temperature water with hot water in a BWR vessel with rare
instances of underclad and shallow cladding cracking appearing in
pressurized water reactor (PWR) nozzles. Feedwater nozzle inner radius
cracking has not been detected since the plants changed operation of
the low flow feedwater controller. Significant inspections and repairs
were required in the late 1970s and early 1980s to address these
problems. The redesign of safe end/thermal sleeve configurations and
feedwater spargers, coupled with changes in operating procedures, has
been effective to date. No further occurrences of nozzle fatigue
cracking have been reported for PWRs or BWRs.
When the new designs and operating procedures appeared to have
mitigated the nozzle inner radius cracking, the ASME BPV Code, Section
XI requirements to inspect steam generator and pressurizer nozzle inner
radii were removed in the 1999 Addenda of ASME BPV Code, Section XI.
Since the NRC imposed the condition requiring that these areas be
inspected in 2002, no new cracking has been identified in steam
generator or pressurizer nozzle inner radii. The NRC finds that the
complete absence of cracking since the operational change provides
reasonable assurance that the observed cracking was the result of
operational practices that have been discontinued. Because the inner
radius inspections were instituted solely based on the observed
cracking and since the cracking mechanism has now been resolved through
changes in operation, the NRC finds that the intended purpose of the
steam generator and pressurizer inner radius exams no longer exists and
that the exams can be discontinued.
In addition to operating experience, the NRC has reviewed the
nozzle inner radii examinations as part of approving alternatives and
granting relief requests concerning inspections of the pressurizer and
steam generator nozzle inner radii. In the safety evaluations for
proposed alternatives, the NRC has concluded that the fatigue analysis
for a variety of plants shows that there is reasonable assurance that
there will not be significant cracking at the steam generator or
pressurizer nozzle inner radii before the end of the operating licenses
of the nuclear power plants.
Therefore, based on the design changes, operating experiences, and
analysis done by industry and the NRC, the NRC proposes to remove Sec.
55.55a(b)(2)(xxi)(A), which requires the inspection of pressurizer and
steam generator nozzle inner radii.
10 CFR 50.55a(b)(2)(xxi)(B) Section XI Condition: Table IWB-2500-1
Examination Requirements
The NRC is proposing to add a new paragraph (b)(2)(xxi)(B) that
will place conditions on the use of the provisions of IWB-2500(f) and
(g) and Notes 6 and 7 of Table IWB-2500-1 of the 2017 Edition of ASME
BPV Code, Section XI. These provisions would allow licensees of BWRs to
reduce the number of Item Number B3.90 and B3.100 components to be
examined from 100 percent to 25 percent. These conditions would require
licensees using the provisions of IWB-2500(f) to maintain the
evaluations that determined the plant satisfied the criteria of IWB-
2500(f) as records in accordance with IWA-1400. The conditions would
prohibit use of a new provision in Section XI, 2017 Edition, Table
2500-1 Category B-D, Full Penetration Welded Nozzles in Vessels, Items
B3.90 and B3.100, specific to BWR nuclear power plants with renewed
operating licenses or renewed combined licensees in accordance with 10
CFR part 54. The final condition would not allow the use of these
provisions to eliminate preservice or inservice volumetric examinations
of plants with a Combined Operating License pursuant to 10 CFR part 52,
or a plant that receives its operating license after October 22, 2015.
[[Page 56166]]
The addition of these provisions addresses the incorporation of
Code Case N-702, ``Alternative Requirements for Boiling Water Reactor
(BWR) Nozzle Inner Radius and Nozzle-to-Shell Welds Section XI,
Division 1 into the Code. The proposed conditions are consistent with
those proposed for Regulatory Guide 1.147, ``Inservice Inspection Code
Case Acceptability, ASME Section XI, Division 1,'' Revision 19.
The NRC finds that eliminating the volumetric preservice or
inservice examination, as would be allowed by implementing the
provisions of IWB-2500(g) and Note 7 of Table IWB-2500-1, should be
predicated on good operating experience for the existing fleet, which
has not found any inner radius cracking in the nozzles within scope of
the code case. New reactor designs do not have any operating
experience; therefore, the proposed condition will ensure that new
reactors would perform volumetric examinations of nozzle inner radii to
gather operating experience.
10 CFR 50.55a(b)(2)(xxv) Section XI Condition: Mitigation of Defects by
Modification
The NRC proposes to amend the condition found in Sec.
50.55a(b)(2)(xxv) to allow the use of IWA-4340 of ASME BPV Code,
Section XI, 2011 Addenda through 2017 Edition with conditions. The
modification of Sec. 50.55a(b)(2)(xxv) would add paragraph (A) and
would continue the prohibition of IWA-4340 for Section XI editions and
addenda prior to the 2011 Addenda. It would also add paragraph (B),
which would contain the three conditions that the NRC is proposing to
place on the use of IWA-4340 of Section XI, 2011 Addenda through 2017
Edition.
10 CFR 50.55a(b)(2)(xxv)(A) Mitigation of Defects by Modification:
First Provision
The NRC proposes to add paragraph (b)(2)(xxv)(A), which would
continue the prohibition of IWA-4340 for Section XI editions and
addenda prior to the 2011 Addenda. IWA-4340 as originally incorporated
into Section XI, Subsubarticle IWA-4340 did not include critical
requirements that were incorporated into later editions of Section XI
such as: (a) Characterization of the cause and projected growth of the
defect; (b) verification that the flaw is not propagating into material
credited for structural integrity; (c) prohibition of repeated
modifications where a defect area grew into the material required for
the modification; and (d) pressure testing. Therefore, the NRC
prohibited the use of IWA-4340 in its original form. This new paragraph
would be necessary to maintain the prohibition because the NRC, as
described in the following paragraph, is proposing to allow the use of
IWA-4340 of Section XI, 2011 Addenda through 2017 Edition.
10 CFR 50.55a(b)(2)(xxv)(B) Mitigation of Defects by Modification:
Second Provision
The NRC proposes to add paragraph (b)(2)(xxv)(B) to allow the use
of IWA-4340 of Section XI, 2011 Addenda through 2017 Edition with three
conditions. The NRC finds that IWA-4340 as incorporated into later
editions of Section XI was improved with requirements such as: (a)
Characterization of the cause and projected growth of the defect; (b)
verification that the flaw is not propagating into material credited
for structural integrity; (c) prohibition of repeated modifications
where a defect area grew into the material required for the
modification; and (d) pressure testing. With inclusion of these
requirements and those stated in the following conditions, the NRC
concludes that there are appropriate requirements in place to provide
reasonable assurance that the modification will provide an adequate
pressure boundary, even while considering potential growth of the
defect. The conditions and the basis for each are as follows:
The first proposed condition would prohibit the use of
IWA-4340 on crack-like defects or those associated with flow
accelerated corrosion. The design requirements and potentially the
periodicity of follow-up inspections might not be adequate for crack-
like defects that could propagate much faster than defects due to loss
of material. Therefore, the NRC proposes to prohibit the use of IWA-
4340 on crack-like defects. Loss of material due to flow accelerated
corrosion is managed by licensee programs based on industry standards.
The periodicity of follow-up inspections is best managed by plant-
specific flow accelerated corrosion programs. In addition, subparagraph
IWA-4421(c)(2) provides provisions for restoring minimum required wall
thickness by welding or brazing, including loss of material due to flow
accelerated corrosion.
The second proposed condition would require the design of
a modification that mitigates a defect to incorporate a loss of
material rate either 2 times the actual measured corrosion rate in the
location, or 4 times the estimated maximum corrosion rate for the
piping system. Corrosion rates are influenced by local conditions
(e.g., flow rate, discontinuities). The condition to extrapolate a loss
of material rate either 2 times the actual measured corrosion rate in
the location, or 4 times the estimated maximum corrosion rate for the
system is consistent with ASME Code Cases N-786-1, ``Alternative
Requirements for Sleeve Reinforcement of Class 2 and 3 Moderate Energy
Carbon Steel Piping,'' and N-789, ``Alternative Requirements for Pad
Reinforcement of Class 2 and 3 Moderate Energy Carbon Steel Piping for
Raw Water Service.'' The NRC concludes that these multipliers are
appropriate if the wall thickness measurements in the vicinity of the
defect were only obtained once. In contrast, if wall thickness
measurements were obtained in two or more refueling outage cycles, the
NRC concludes that there is a sufficient span of time to be able to
trend the corrosion rate into the future. This conclusion is based in
part on the follow-up wall thickness measurements that are conducted
subsequent to installation of the modification.
The third proposed condition would require the Owner to
perform a wall thickness examination in the vicinity of the
modification and relevant pipe base metal during each refueling outage
cycle to detect propagation of the flaw into the material credited for
structural integrity of the item, unless the examinations in the two
refueling outage cycles subsequent to the installation of the
modification are capable of validating the projected flaw growth. The
NRC concludes that the provision allowed by subparagraph IWA-4340(g) to
conduct follow-up wall thickness measurements only to the extent that
they demonstrate that the defect has not propagated into the material
credited for structural integrity is not sufficient because it does not
provide a verification of the projected flaw growth. Subparagraph IWA-
4340(h) does not fully address the NRC's concern because it allows for
projected flaw growth to be based on ``prior Owner or industry
experiences with the same conditions'' instead of specific measurements
in the location of the modification. The proposed condition allows for
only conducting examinations in the two refueling outages subsequent to
the installation of the modification, consistent with subparagraph IWA-
4340(g), if the measurements are capable of projecting the flaw growth.
[[Page 56167]]
10 CFR 50.55a(b)(2)(xxvi) Section XI Condition: Pressure Testing Class
1, 2 and 3 Mechanical Joints
The NRC proposes to amend the condition found in Sec.
50.55a(b)(2)(xxvi) to clarify the NRC's expectations related to the
pressure testing of ASME BPV Code Class 1, 2, and 3 mechanical joints
disassembled and reassembled during the performance of an ASME BPV
Code, Section XI activity. Industry stakeholders have expressed
confusion with the current regulatory requirements with regard to when
a pressure test was required and which year of the Code the pressure
testing should be in compliance with in accordance with this condition.
The NRC proposes to modify the condition to clarify that all mechanical
joints in Class 1, 2 and 3 piping and components greater than NPS-1
that are disassembled and reassembled during the performance of a
Section XI activity (e.g., a repair/replacement activity) shall be
pressure tested in accordance with IWA-5211(a). The pressure testing
shall be performed using procedures and personnel meeting the
requirements of the licensee's/applicant's current code of record. This
condition was first put in place by the NRC in the final rule effective
November 1, 2004 (69 FR 58804). The NRC determined that the condition
was necessary because the ASME BPV Code eliminated the requirements to
pressure test Class 1, 2, and 3 mechanical joints undergoing repair and
replacement activities in the 1999 Addenda. The NRC finds that pressure
testing of mechanical joints affected by repair and replacement
activities is necessary to ensure and verify the leak tight integrity
of the system pressure boundary.
10 CFR 50.55a(b)(2)(xxxii) Section XI Condition: Summary Report
Submittal
The NRC proposes to amend the condition found in Sec.
50.55a(b)(2)(xxxii) to address the use of Owner Activity Reports.
Through the 2013 Edition of ASME BPV Code, Section XI, Owners were
required to prepare Summary Reports of preservice and inservice
examinations and repair replacement activities. This condition was
added when the 2013 Edition was incorporated by reference because up
until that time, Owners were required to submit these reports to the
regulatory authority having jurisdiction of the plant site. The 2013
Edition removed the requirement for submittal from IWA-6240(c), to
state that submittal was only mandatory if required by the authority.
The NRC added the condition in paragraph (b)(2)(xxxii) to require
submittal of Summary Reports. In the 2015 Edition of ASME BPV Code,
Section XI the title of these reports was changed from Summary Reports
to Owner Activity Reports. Therefore, the NRC is proposing to amend the
condition to also require the submittal of Owner Activity Reports.
10 CFR 50.55a(b)(2)(xxxiv) Section XI Condition: Nonmandatory Appendix
U
The NRC proposes to amend the requirements in current paragraph
(b)(2)(xxxiv) to make the condition applicable to the latest edition
incorporated by reference in paragraph (a)(1)(ii) of Sec. 50.55a. The
current condition in paragraph (b)(2)(xxxiv)(A) requires repair and
replacement activities temporarily deferred under the provisions of
Nonmandatory Appendix U to be performed during the next scheduled
refueling outage. This condition was added when the 2013 Edition was
incorporated by reference. When ASME published the 2015 Edition and the
2017 Editions, Nonmandatory Appendix U was not modified in a way that
would make it possible for the NRC to remove this condition. Therefore,
the NRC is proposing to retain this condition to apply to the latest
edition incorporated by reference in paragraph (a)(1)(ii) of Sec.
50.55a. The current condition in paragraph (b)(2)(xxxiv)(B) requires a
mandatory appendix in ASME Code Case N-513-3 to be used as the
referenced appendix for paragraph U-S1-4.2.1(c). This condition was
also added when the 2013 Edition was incorporated by reference. The
omission that made this condition necessary was remedied in the 2017
Edition. Therefore, the NRC is proposing to retain this condition to
apply to only to the 2013 and the 2015 Editions.
10 CFR 50.55a(b)(2)(xxxv) Section XI Condition: Use of RTT0
in the KIa and KIc Equations
The NRC proposes to re-designate the requirements in current
paragraph (b)(2)(xxxv), that address the use of the 2013 Edition of
ASME BPV Code, Section XI, Appendix A, paragraph A-4200, as
(b)(2)(xxxv)(A). The ASME BPV Code has addressed the NRC concern
related to this condition in the 2015 Edition; however, it is still
relevant to licensees/applicants using the 2013 Edition. The NRC
proposes to add a new paragraph (b)(2)(xxv)(B) to condition the use of
2015 Edition of ASME BPV Code, Section XI, Appendix A, paragraph A-
4200(c), to require the use of the equation RTKIa = T0 +
90.267 exp(-0.003406T0) in lieu of the equation (a), shown in the Code.
Paragraph A-4200(c) was added in the 2015 Edition to provide for an
alternative method in establishing a fracture-toughness-based reference
temperature, RTT0, for pressure retaining materials, using
fracture toughness test data. Equation (b) was derived from test data
using the International System of Units (SI units). Equation (a) was a
converted version of equation (b) using U.S Customary units.
Unfortunately, an error was made in the conversion, which makes
equation (a) incorrect. The equation shown in this paragraph for
RTKIa is the correct formula.
10 CFR 50.55a(b)(2)(xxxvi) Section XI Condition: Fracture Toughness of
Irradiated Materials
The NRC proposes to amend the condition found in Sec.
50.55a(b)(2)(xxxvi) to extend the applicability to use of the 2015 and
2017 Editions of ASME BPV Code, Section XI. This current condition
requires licensees using ASME BPV Code, Section XI, 2013 Edition,
Appendix A, paragraph A-4400, to obtain NRC approval before using
irradiated T0 and the associated RTT0 in
establishing fracture toughness of irradiated materials. This condition
was added when the 2013 Edition was incorporated by reference because
the newly introduced A-4200(b) could mislead the users of Appendix A
into adopting methodology that is not accepted by the NRC. When ASME
published the 2015 Edition and the 2017 Editions, Appendix A of the
ASME BPV Code, Section XI was not modified in a way that would make it
possible for the NRC to remove this condition. Therefore, the NRC is
proposing to retain this condition to apply to the 2015 and 2017
Editions.
10 CFR 50.55a(b)(2)(xxxviii) Section XI Condition: ASME Code Section XI
Appendix III Supplement 2
The NRC proposes to add Sec. 50.55a(b)(2)(xxxviii) to condition
ASME BPV Code, Section XI Appendix III Supplement 2. Supplement 2 is
closely-based on ASME Code Case N-824, which was incorporated by
reference with conditions in Sec. 50.55a(b)(2)(xxxvii). The conditions
on ASME BPV Code, Section XI Appendix III Supplement 2 are consistent
with the conditions on ASME Code Case N-824, published in July 18, 2017
(82 FR 32934).
The conditions are derived from research into methods for
inspecting Cast Austenitic Stainless Steel (CASS) components; these
methods are published in NUREG/CR-6933, ``Assessment of Crack Detection
in
[[Page 56168]]
Heavy-Walled Cast Stainless Steel Piping Welds Using Advanced Low-
Frequency Ultrasonic Methods,'' (ADAMS Accession Nos. ML071020410 and
ML071020414), and NUREG/CR-7122, ``An Evaluation of Ultrasonic Phased
Array Testing for Cast Austenitic Stainless Steel Pressurizer Surge
Line Piping Welds,'' (ADAMS Accession No. ML12087A004). These NUREG/CR
reports show that CASS materials less than 1.6 inches thick can be
reliably inspected for flaws 10 percent through-wall or deeper if
encoded phased-array examinations are performed using low ultrasonic
frequencies and a sufficient number of inspection angles. Additionally,
for thicker welds, flaws greater than 30 percent through-wall in depth
can be detected using low frequency encoded phased-array ultrasonic
inspections.
The NRC, using NUREG/CR-6933 and NUREG/CR-7122, has determined that
sufficient technical basis exists to condition ASME BPV Code, Section
XI, Appendix III Supplement 2. The NUREG/CR reports show that CASS
materials produce high levels of coherent noise and that the noise
signals can be confusing and mask flaw indications. The optimum
inspection frequencies for examining CASS components of various
thicknesses as described in NUREG/CR-6933 and NUREG/CR-7122 are
reflected in proposed condition Sec. 50.55a(b)(2)(xxxviii)(A). As
NUREG/CR-6933 shows that the grain structure of CASS can reduce the
effectiveness of some inspection angles, the NRC finds sufficient
technical basis for the use of ultrasound using angles including, but
not limited to, 30 to 55 degrees, with a maximum increment of 5
degrees. This is reflected in proposed condition Sec.
50.55a(b)(2)(xxxviii)(B).
10 CFR 50.55a(b)(2)(xxxix)(A) Defect Removal: First Provision
The NRC proposes to add Sec. 50.55a(b)(2)(xxxix)(A) to place
conditions on the use of ASME BPV Code, Section XI, IWA-4421(c)(1). The
condition establishes that the final configuration of the item will be
in accordance with the original Construction Code, later editions and
addenda of the Construction Code, or a later different Construction
Code, as well as meeting the Owner's Requirements or revised Owner's
Requirements. This condition would ensure that welding, brazing,
fabrication, and installation requirements, as well as design
requirements for material, design or configuration changes, are
consistent with the Construction Code and Owner's Requirements. This
condition retains the intent of the revision to Section XI that: (a)
Replacements in kind are acceptable; (b) replacements with alternative
configurations are acceptable as long as Construction Code and Owner's
Requirements are met; and (c) defect removal is required; however, this
can be accomplished by replacing all or a portion of the item
containing the defect.
10 CFR 50.55a(b)(2)(xxxix)(B) Defect Removal: Second Provision
The NRC proposes to add Sec. 50.55a(b)(2)(xxxix)(B) to place
conditions on the use of ASME BPV Code, Section XI, IWA-4421(c)(2). The
inclusion of subparagraph IWA-4421(c)(2) is intended to address wall
thickness degradation where the missing wall thickness is restored by
weld metal deposition. This repair activity restores the wall thickness
to an acceptable condition; however, it does not ``remove'' the
degraded wall thickness (i.e., the defect); rather, restoration of wall
thickness by welding or brazing mitigates the need to remove the
defect. However, increasing the wall thickness of an item to reclassify
a crack from a defect to a flaw \3\ is not acceptable because there are
no provisions in subparagraph IWA-4421(c)(2) for analyses and ongoing
monitoring of potential crack growth. Therefore, this proposed
condition would prohibit the use of subparagraph IWA-4421(c)(2) rather
than replacement for crack-like defects.
---------------------------------------------------------------------------
\3\ As defined in ASME BPV Code, Section XI, Article IWA-9000, a
``flaw'' is as an imperfection or unintentional discontinuity that
is detectable by nondestructive examination and a ``defect'' is
defined as a flaw of such size, shape, orientation, location, or
properties as to be rejectable.
---------------------------------------------------------------------------
10 CFR 50.55a(b)(2)(xl) Section XI Condition: Prohibitions on Use of
IWB-3510.4(b)
The NRC proposes to add Sec. 50.55a(b)(2)(xl) to prohibit the use
of ASME BPV Code, Section XI, Subparagraphs IWB-3510.4(b)(4) and IWB-
3510.4(b)(5), which allow use of certain acceptance standard tables for
high yield strength ferritic materials because they are not supported
by the fracture toughness data.
The ASME BPV Code, Section XI, Subarticle IWB-3500 provides
acceptance standards for pressure retaining components made of ferritic
steels. Subparagraph IWB-3510.4 specifies material requirements for
ferritic steels for application of the acceptance standards. In prior
editions of the ASME BPV Code, Section XI, the material requirements
for ferritic steels for which the acceptance standards of IWB-3500
apply are included in a note under the title of tables that specify
allowable flaw sizes (e.g., Table IWB-3510-1 ``Allowable Planar
Flaws''). Subparagraph IWB-3510.4 separates ferritic materials into
three groups: (a) Those with a minimum yield strength of 50 ksi or
less, (b) five ferritic steels with these material designations: SA-508
Grade 2 Class 2 (former designation: SA-508 Class 2a), SA-508 Grade 3
Class 2 (former designation: SA-508 Class 3a), SA-533 Type A Class 2
(former designation: SA-533 Grade A Class 2), SA-533 Type B Class 2
(former designation: SA-533 Grade B Class 2), and SA-508 Class 1, and
(c) those with greater than 50 ksi but not exceeding 90 ksi. The
material requirements for ferritic steels with a minimum yield strength
of 50 ksi or less and those with greater than 50 ksi but not exceeding
90 ksi are explicitly specified. However, there are no material
requirements for the five ferritic steels identified above.
The NRC finds Subparagraph IWB-3510.4(a) acceptable because it is
consistent with the current material requirements for ferritic steels
having a minimum yield strength of 50 ksi or less. The NRC finds
Subparagraph IWB-3510.4(c) acceptable because it is consistent with the
current material requirements for ferritic steels having a minimum
yield strength of greater than 50 ksi to 90 ksi.
The NRC does not find Subparagraphs IWB-3510.4(b)(4) and (5)
acceptable for the following reasons. The NRC plotted the ASME BPV
Code, Section XI static plain-strain fracture toughness
(KIC) curve in relevant figures in an ASME conference paper,
PVP2010-25214, ``Fracture Toughness of Pressure Boundary Steels with
Higher Yield Strength'' that shows dynamic fracture toughness
(KID) data for materials listed in IWB-3510.4 (b)(1) to IWB-
3510.4 (b)(4). The NRC confirmed that the materials listed in IWB-
3510.4 (b)(1) and IWB-3510.4 (b)(3) are acceptable because the data are
above the KIC curve with adequate margin to compensate for
the limited data size. Additionally, the NRC has approved the use of
the materials listed in IWB-3510.4 (b)(1) and IWB-3510.4 (b)(3) in a
licensing and a design certification application. For the material
listed in IWB-3510.4 (b)(2), KID data was demonstrated to be
above the crack arrest fracture toughness (KIa). The NRC has
previously determined the KIa fracture toughness standard to
be acceptable. Hence, the materials listed in IWB-3510.4 (b)(2) are
acceptable. However, the technical basis document does not provide
sufficient data to support exclusion of the fracture
[[Page 56169]]
toughness requirements for the materials specified in Subparagraphs
IWB-3510.4(b)(4) and IWB-3510.4(b)(5).
This proposed condition does not change the current material
requirements because licensees/applicants may continue to use testing
to show that the two prohibited materials meet the material
requirements.
10 CFR 50.55a(b)(2)(xli) Section XI Condition: Preservice Volumetric
and Surface Examinations Acceptance
The NRC proposes to add Sec. 50.55a(b)(2)(xli) to prohibit the use
of ASME BPV Code, Section XI, Subparagraphs IWB-3112(a)(3) and IWC-
3112(a)(3) in the 2013 through 2017 Edition. The NRC is prohibiting
these items consistent with a final rule that approved ASME BPV Code
Cases for use, dated January 17, 2018, (83 FR 2331).
During the review of public comments that were submitted on the
proposed rule, dated March 2, 2016, (81 FR 10780), the NRC identified
inconsistencies between Regulatory Guide 1.193, ``ASME Code Cases Not
Approved for Use,'' Revision 5, and a then concurrent proposed rule to
incorporate by reference the 2009-2013 Editions of the ASME BPV Code
(80 FR 56819), dated December 2, 2015.
Specifically, conditions that pertain to the staff's disapproval of
Code Case N-813, ``Alternative Requirements for Preservice Volumetric
and Surface Examination,'' in the ASME BPV Code Regulatory Guide 1.193
proposed rule were not included in the ASME BPV 2009-2013 Editions
proposed rule; however, the content of Code Case N-813 had been
incorporated in the 2013 Edition of the ASME Code, Section XI. In order
to resolve this conflict, the NRC excluded from the incorporation by
reference those applicable portions of Section IX in the 2011a Addenda
and the 2013 Edition, in Sec. 50.55a(a)(1)(ii)(C)(52) and (53)
respectively. This allowed the NRC to develop an appropriate regulatory
approach for the treatment of these provisions that is consistent with
the ASME BPV Code Regulatory Guide 1.193 rulemaking, in which the NRC
found the acceptance of preservice flaws by analytical evaluation
unacceptable.
Code Case N-813 is a proposed alternative to the provisions of the
2010 Edition of the ASME Code, Section XI, paragraph IWB-3112.
Paragraph IWB-3112 does not allow the acceptance of flaws detected in
the preservice examination by analytical evaluation. Code Case N-813
would allow the acceptance of these flaws through analytical
evaluation. Per paragraph IWB-3112, any preservice flaw that exceeds
the acceptance standards of Table IWB-3410-1 must be removed. While it
is recognized that operating experience has shown that large through-
wall flaws and leakages have developed in previously repaired welds as
a result of weld residual stresses, the NRC has the following concerns
regarding the proposed alternative in Code Case N-813:
(1) The requirements of paragraph IWB-3112 were developed to ensure
that defective welds were not placed in service. The NRC finds that a
preservice flaw detected in a weld that exceeds the acceptance
standards of Table IWB-3410-1 demonstrates poor workmanship and/or
inadequate welding practice and procedures. The NRC finds that such an
unacceptable preservice flaw needs to be removed and the weld needs to
be repaired before it is placed in service.
(2) Under Code Case N-813, large flaws would be allowed to remain
in service because paragraph IWB-3132.3, via paragraph IWB-3643, allows
a flaw up to 75 percent through-wall to remain in service. The NRC
finds that larger flaws could grow to an unacceptable size between
inspections, reducing structural margin and potentially challenging the
structural integrity of safety-related Class 1 and Class 2 piping.
Paragraph C-3112(a)(3) of Code Case N-813, provides the same
alternatives for Class 2 piping as that of Paragraph B-3122(a)(3). The
NRC has the same concerns for Class 2 piping as for Class 1 piping.
Therefore, for the acceptance of preservice flaws by analytical
evaluation, the NRC proposes to add a condition that prohibits the use
of IWB-3112(a)(3) and IWC-3112(a)(3) in the 2013 Edition of ASME BPV
Code Section XI through the latest edition and addenda incorporated by
reference in paragraph (a)(1)(ii) of Sec. 50.55a.
10 CFR 50.55a(b)(2)(xlii) Section XI Condition: Steam Generator Nozzle-
to-Component Welds and Reactor Vessel Nozzle-to-Component Welds
The NRC proposes to add Sec. 50.55a(b)(2)(xlii) to require that
the examination of Steam Generator Nozzle-to-Component welds and
Reactor Vessel Nozzle-to-Component welds must be a full volume
examination and that the ultrasonic examination procedures, equipment,
and personnel must be qualified by performance demonstration in
accordance with Mandatory Appendix VIII of ASME Code, Section XI. These
proposed conditions are consistent with the conditions on ASME Code
Case N-799 in Regulatory Guide 1.147, Revision 18, which was
incorporated by reference in Sec. 50.55a in the final rule that
approved ASME BPV Code Cases for use, dated January 17, 2018 (83 FR
2331). The NRC is adding this condition in order to be consistent with
that final rule.
During the review of the public comments that were submitted on the
proposed rule, dated March 2, 2016, (81 FR 10780), the NRC identified
inconsistencies between Regulatory Guide 1.147, and a then concurrent
proposed rule to incorporate by reference the 2009-2013 Editions of the
ASME BPV Code (80 FR 56819), dated December 2, 2015.
Specifically, conditions that pertain to Code Case N-799,
``Dissimilar Metal Welds Joining Vessel Nozzles to Components,'' in the
ASME BPV Code Regulatory Guide 1.147 proposed rule were not included in
the ASME BPV 2009-2013 Editions proposed rule. However, the content of
Code Case N-799 had been incorporated in the 2013 Edition of the ASME
Code, Section XI. In order to resolve this conflict, the NRC excluded
from the incorporation by reference those applicable portions of
Section IX in the 2011a Addenda and the 2013 Edition, in Sec.
50.55a(a)(1)(ii)(C)(52) and (53), respectively. This allowed the NRC to
develop an appropriate regulatory approach for the treatment of these
provisions that is consistent with the ASME BPV Code Regulatory Guide
1.147 final rule, in which the NRC required that the examination of the
aforementioned welds must be full volume and that the ultrasonic
examination procedures, equipment, and personnel must be qualified by
performance demonstration in accordance with Mandatory Appendix VIII of
ASME Code, Section XI.
Of particular interest to the NRC is the condition requiring the
examination of dissimilar metal welds between vessel nozzles and
components to be full volume and the condition for requiring
performance demonstration in accordance with Mandatory Appendix VIII of
ASME Code, Section XI. The following focuses on the AP1000 design,
although a similar issue exists for the reactor vessel-to-reactor
coolant pump connection for the Advanced Boiling Water Reactor (ABWR)
design.
The AP1000 design is unique in that a reactor coolant pump is
welded directly to each of the two outlet nozzles on the steam
generator channel head. This steam generator nozzle to reactor coolant
pump casing (SG-to-RCP) weld is a dissimilar metal (low alloy steel to
[[Page 56170]]
cast austenitic stainless steel with Alloy 52/152 weld metal)
circumferential butt weld with a double sided weld joint configuration
similar to that of a reactor vessel shell weld. Also, this unique
component-to-component weld is part of the reactor coolant pressure
boundary and therefore subject to the examination requirements of ASME
Section XI, Subsection IWB. However, prior to the development of Code
Case N-799 (since incorporated into ASME Section XI, IWB-2500, as part
of the 2011 Addenda), the examination requirements for the SG-to-RCP
welds were not addressed in the ASME Code.
The NRC's first concern is that the examinations required by Code
Case N-799 do not provide assurance that the integrity of the SG-to-RCP
welds will be maintained throughout the operating life of the AP1000
plant. Traditionally, ASME Section XI, IWB-2500 requires a full volume
examination of all component welds, except those welds found in piping
and those found in nozzles welded to piping. However, Code Case N-799
only requires a licensee to perform a volumetric examination of the
inner \1/3\ of the weld and a surface examination of the outer
diameter. The NRC finds that the requirements of Code Case N-799 are
identical to those in ASME Section XI, Table IWB-2500-1, Examination
Category B-F for welds between vessels nozzles larger than NPS 4 and
piping. As such, the NRC finds that the examination requirements
proposed in Code Case N-799 are not appropriate for the SG-to-RCP weld
because the service conditions of this weld are significantly different
from those that would be experienced by a traditional vessel nozzle-to-
piping/safe end butt weld.
Specifically, in addition to the operating environment (RCS
pressure, temperature, and exposure to coolant) and loads expected on a
traditional nozzle-to-safe end weld, each SG-to-RCP weld will support
the full weight of a reactor coolant pump with no other vertical or
lateral supports. The SG-to-RCP welds will also be subject to pump
rotational forces and vibration loads from both the steam generator and
the reactor coolant pump. In the absence of operating experience for
the weld in question or a bounding analysis, which demonstrates that a
potential fabrication defect in the outer \2/3\ of the weld will not
experience subcritical crack growth, the NRC finds that the effects of
these additional operating loads and stresses are unknown. Absent
operating experience or a bounding analysis, the NRC finds that it is
inappropriate to allow a reduced examination volume at this time.
Therefore, the NRC is proposing that the examination of the
aforementioned welds must be full volume.
The NRC's second concern is that the examinations required by Code
Case N-799 do not provide assurance that inservice degradation can be
detected for this dissimilar metal weld that includes CASS. Code Case
N-799 does not require the use of performance demonstration in
accordance with Mandatory Appendix VIII of the ASME Code, Section XI.
The NRC finds that ultrasonic inspection of CASS material is difficult
due to the grain structure of the material. In order to have a
meaningful ultrasonic examination to detect and size inservice
degradation, the ultrasonic examination procedures, equipment, and
personnel must be qualified by performance demonstration in accordance
with Mandatory Appendix VIII of ASME Code, Section XI. This is
consistent with current practices for other ultrasonic examinations of
dissimilar metal welds in the operating fleet.
When considering these proposed conditions, the NRC recognizes that
factors exist that may limit the ultrasonic examination volume that can
be qualified by performance demonstration. For example, the qualified
volume would be limited in components with wall thicknesses beyond the
crack detection and sizing capabilities of a through wall ultrasonic
performance-based qualification. To address the scenario in which the
examination volume that can be qualified by performance demonstration
is less than 100 percent of the volume, the NRC is proposing to allow
an ultrasonic examination of the qualified volume, provided that a flaw
evaluation is performed to demonstrate the integrity of the examination
volume that cannot be qualified by performance demonstration. The flaw
evaluation should be of the largest hypothetical crack that could exist
in the volume not qualified for ultrasonic examination. The licensee's
revised examination plan would be subject to prior NRC approval as an
alternative in accordance with Sec. 50.55a(z). The NRC believes that
this proposed condition provides assurance that the integrity of the
welds in question will be maintained, despite a limited examination
capability.
Finally, these proposed conditions are consistent with the
conditions described in Regulatory Guide 1.147, Revision 18, which
conditionally accepts Code Case N-799. Because Code Case N-799 has been
incorporated into ASME Section XI, the NRC's conditions on the Code
Case will be carried over as a condition on the ASME Code.
Therefore, in order to ensure that the examinations of Steam
Generator Nozzle-to-Component welds and Reactor Vessel Nozzle-to-
Component welds will be examinations of the full volume of the welds
and that the ultrasonic examination procedures, equipment, and
personnel are qualified by performance demonstration, in accordance
with Mandatory Appendix VIII of ASME Code, Section XI, the NRC proposes
to add conditions to the provisions of Table IWB-2500-1, Examination
Category B-F, Pressure Retaining Dissimilar Metal Welds in Vessel
Nozzles, Item B5.11 (NPS 4 or Larger Nozzle-to-Component Butt Welds) of
the 2013 Edition through the latest edition and addenda incorporated by
reference in paragraph (a)(1)(ii) of Sec. 50.55a. The NRC also
proposes to add a condition to the provision of Table IWB-2500-1, Item
B5.71 (NPS 4 or Larger Nozzle-to-Component Butt Welds) of the 2011
Addenda through the latest edition and addenda incorporated by
reference in paragraph (a)(1)(ii) of Sec. 50.55a.
C. ASME OM Code
10 CFR 50.55a(b)(3), Conditions on ASME OM Code
The new Appendix IV in the 2017 Edition of the ASME OM Code
provides improved preservice testing (PST) and IST of active air
operated valves (AOVs) within the scope of the ASME OM Code. Appendix
IV specifies quarterly stroke-time testing of AOVs, where practicable.
These are similar to the current requirements in Subsection ISTC,
``Inservice Testing of Valves in Light-Water Reactor Nuclear Power
Plants,'' of the ASME OM Code. In addition, Appendix IV specifies a
preservice performance assessment test for AOVs with low safety
significance, and initial and periodic performance assessment testing
for AOVs with high safety significance on a sampling basis over a
maximum 10-year interval.
The ASME developed the improved PST and IST provisions for AOVs in
Appendix IV to the ASME OM Code in response to lessons learned from
operating experience and test programs for AOVs and other power-
operated valves (POVs) used at nuclear power plants. Over the years,
the NRC has issued numerous generic communications to address
weaknesses with AOVs and other POVs in performing their safety
functions. For example, the NRC issued Generic Letter (GL) 88-14,
``Instrument Air Supply System Problems Affecting Safety-Related
Equipment,'' to request that licensees verify that AOVs will perform
[[Page 56171]]
as expected in accordance with all design-basis events. The NRC
provided the results of studies of POV issues in several documents,
including NUREG/CR-6654, ``A Study of Air-Operated Valves in U.S.
Nuclear Power Plants'' (ADAMS Accession No. ML003691872). The NRC has
issued several information notices to alert licensees to IST experience
related to POV performance, including IN 86-50, ``Inadequate Testing To
Detect Failures of Safety-Related Pneumatic Components or Systems;''
and IN 85-84, ``Inadequate Inservice Testing of Main Steam Isolation
Valves.'' The NRC issued IN 96-48, ``Motor-Operated Valve Performance
Issues,'' which described lessons learned from motor-operated valve
(MOV) programs that are applicable to other POVs. Based on operating
experience with the capability of POVs to perform their safety
functions, the NRC established Generic Safety Issue 158, ``Performance
of Safety-Related Power-Operated Valves Under Design-Basis
Conditions,'' to evaluate whether additional regulatory actions were
necessary to address POV performance issues. In Regulatory Issue
Summary 2000-03, ``Resolution of Generic Safety Issue (GSI) 158,
`Performance of Safety Related Power-Operated Valves Under Design-Basis
Conditions','' dated March 15, 2000, the NRC closed GSI-158 by
specifying attributes for an effective POV testing program that
incorporates lessons learned from MOV research and testing programs.
More recently, the NRC issued IN 2015-13, ``Main Steam Isolation Valve
Failure Events,'' to alert nuclear power plant applicants and licensees
to examples of operating experience where deficiencies in licensee
processes and procedures can contribute to the failure of main steam
isolation valves (MSIVs), which may be operated by air actuators or
combined air/hydraulic actuators. The NRC considers that the improved
IST provisions specified in Appendix IV to the ASME OM Code will
address the POV performance issues identified by operating experience
with AOVs, including MSIVs, at nuclear power plants.
Paragraph IV-3800, ``Risk-Informed AOV Inservice Testing,'' allows
the establishment of risk-informed AOV IST that incorporates risk
insights in conjunction with functional margin to establish AOV
grouping, acceptance criteria, exercising requirements, and testing
intervals. Risk-informed AOV IST includes initial and periodic
performance assessment testing of high-safety significant AOVs with the
results of that testing used to confirm the capability of low-safety
significant AOVs within the same AOV group. For example, paragraph IV-
3600, ``Grouping of AOVs for Performance Assessment Testing,'' states
that test results shall be evaluated for all AOVs in a group. Paragraph
IV-6500, ``Performance Assessment Test Corrective Action,'' specifies
that correction action be taken in accordance with the Owner's
corrective action requirements if AOV performance is unacceptable. The
NRC considers that these provisions in Appendix IV will provide
assurance that all AOVs within the scope of Appendix IV will be
addressed for their operational readiness initially and on a periodic
basis. The NRC is proposing to revise the last sentence of Sec.
50.55a(b)(3) to specify that when implementing the ASME OM Code,
conditions are applicable only as specified in (b)(3).
10 CFR 50.55a(b)(3)(ii) OM Condition: Motor-Operated Valve (MOV)
Testing
The NRC proposes to amend Sec. 50.55a(b)(3)(ii) to specify that
the condition applies to the latest edition and addenda of the ASME OM
Code incorporated by reference in Sec. 50.55a(a)(1)(iv). This will
allow future rulemakings to revise Sec. 50.55a(a)(1)(iv) to
incorporate the latest edition of the ASME OM Code without the need to
revise Sec. 50.55a(b)(3)(ii).
10 CFR 50.55a(b)(3)(iv) OM Condition: Check Valves (Appendix II)
The NRC proposes to amend Sec. 50.55a(b)(3)(iv) to accept the use
of Appendix II, ``Check Valve Condition Monitoring Program,'' in the
2017 Edition of the ASME OM Code without conditions based on its
updated provisions. For example, Appendix II in the 2017 Edition of the
ASME OM Code incorporates Table II, ``Maximum Intervals for Use When
Applying Interval Extensions,'' as well as other conditions currently
specified in Sec. 50.55a(b)(3)(iv). The NRC also proposes to update
Sec. 50.55a(b)(3)(iv) to apply Table II to Appendix II of the ASME OM
Code, 2003 Addenda through the 2015 Edition. Further, the NRC proposes
to remove the outdated conditions in paragraphs (b)(3)(iv)(A) through
(D) based on their application to older editions and addenda of the
ASME OM Code that are no longer applied at nuclear power plants, and on
the incorporation of those conditions in recent editions and addenda of
the ASME OM Code.
10 CFR 50.55a(b)(3)(viii) OM Condition: Subsection ISTE
The NRC proposes to amend Sec. 50.55a(b)(3)(viii) to specify that
the condition on the use of Subsection ISTE, ``Risk-Informed Inservice
Testing of Components in Light-Water Reactor Nuclear Power Plants,''
applies to the latest edition and addenda of the ASME OM Code
incorporated by reference in Sec. 50.55a(a)(1)(iv). This will allow
future rulemakings to revise Sec. 50.55a(a)(1)(iv) to incorporate the
latest edition of the ASME OM Code without the need to revise Sec.
50.55a(b)(3)(viii).
10 CFR 50.55a(b)(3)(ix) OM Condition: Subsection ISTF
The NRC proposes to amend Sec. 50.55a(b)(3)(ix) to specify that
Subsection ISTF, ``Inservice Testing of Pumps in Water-Cooled Reactor
Nuclear Power Plants--Post-2000 Plants,'' of the ASME OM Code, 2017
Edition, is acceptable without conditions. The NRC also proposes to
amend Sec. 50.55a(b)(3)(ix) to specify that licensees applying
Subsection ISTF in the 2015 Edition of the ASME OM Code shall satisfy
the requirements of Mandatory Appendix V, ``Pump Periodic Verification
Test Program,'' of the ASME OM Code, in addition to the current
requirement to satisfy Appendix V when applying Subsection ISTF in the
2012 Edition of the ASME OM Code. Subsection ISTF in the 2017 Edition
of the ASME OM Code has incorporated the provisions from Appendix V
such that this condition is not necessary for the 2017 Edition of the
ASME OM Code.
10 CFR 50.55a(b)(3)(xi) OM Condition: Valve Position Indication
The NRC proposes to amend Sec. 50.55a(b)(3)(xi) for the
implementation of paragraph ISTC-3700, ``Position Verification
Testing,'' in the ASME OM Code to apply to the 2012 Edition through the
latest edition and addenda of the ASME OM Code incorporated by
reference in Sec. 50.55a(a)(1)(iv). This will allow future rulemakings
to revise Sec. 50.55a(a)(1)(iv) to incorporate the latest edition and
addenda of the ASME OM Code without the need to revise Sec.
50.55a(b)(3)(xi). In addition, the NRC proposes to clarify that this
condition applies to all valves with remote position indicators within
the scope of Subsection ISTC, ``Inservice Testing of Valves in Water-
Cooled Reactor Nuclear Power Plants,'' including MOVs within the scope
of Mandatory Appendix III, ``Preservice and Inservice Testing Active
Electric Motor-Operated Valve Assemblies in Water-Cooled Reactor
Nuclear Power Plants.'' ISTC-3700
[[Page 56172]]
references Mandatory Appendix III for valve position testing of MOVs.
The development of Mandatory Appendix III was intended to verify valve
position indication as part of the diagnostic testing performed on the
intervals established by the appendix. This clarification will ensure
that verification of valve position indication is understood to be
important for all valves with remote position indication addressed in
Subsection ISTC and all of its mandatory appendices.
10 CFR 50.55a(b)(3)(xii) OM Condition: Air-Operated Valves (Appendix
IV)
The NRC proposes to include new Sec. 50.55a(b)(3)(xii) to require
the application of the provisions in Appendix IV of the 2017 Edition of
the ASME OM Code, when implementing the ASME OM Code, 2015 Edition. The
new Appendix IV in the 2017 Edition of the ASME OM Code provides
improved PST and IST of active AOVs within the scope of the ASME OM
Code. This condition would provide consistency in the implementation of
these two new editions of the ASME OM Code.
10 CFR 50.55a(f): Preservice and Inservice Testing Requirements
The NRC regulations in Sec. 50.55a(f) specify that systems and
components of boiling and pressurized water-cooled nuclear power
reactors must meet the requirements for preservice and inservice
testing of the ASME BPV Code and ASME OM Code. Paragraph (f) in Sec.
50.55a states that the requirements for inservice inspection of Class
1, Class 2, Class 3, Class MC, and Class CC components (including their
supports) are located in paragraph (g) in Sec. 50.55a. Applicants and
licensees should note that requirements for inservice examination and
testing of dynamic restraints (snubbers) are located in paragraph
(b)(3)(v) in Sec. 50.55a. The NRC staff is considering this
clarification of the location of inservice examination and testing
requirements for dynamic restraints in Sec. 50.55a(f) and (g) for a
future rulemaking.
10 CFR 50.55a(f)(4)(i): Applicable IST Code: Initial 120-Month Interval
Several stakeholders submitted public comments on the Sec. 50.55a
2009-2013 proposed rule requesting that the time schedule for complying
with the latest ASME Code edition and addenda in Sec. 50.55a(f)(4)(i)
and (g)(4)(i) for the IST and ISI programs, respectively, be relaxed
from the current time interval of 12 months to a new time interval of
24 months prior to the applicable milestones in those paragraphs. The
ASME reiterated this request during an NRC/ASME management public
teleconference that was held on March 16, 2016. During that
teleconference, ASME discussed the challenges associated with meeting
the 12-month time schedule in order to submit timely relief or
alternative requests for NRC review. These comments were outside the
scope of the proposed Sec. 50.55a ASME 2009-2013 rule. However, the
NRC staff indicated that the request would be considered in a future
rulemaking.
In evaluating the suggested change, the NRC has determined that the
primary benefit from the relaxation of this Sec. 50.55a(f)(4)(i)
requirement is that licensees of new nuclear power plants will have
more time to prepare their initial IST program and procedures and any
proposed relief or alternative requests to the applicable edition of
the ASME OM Code. In preparing this proposed rule, the NRC has
determined that relaxation of the time schedule for satisfying the
latest edition of the ASME OM Code for the initial 120-month IST
interval to be appropriate. However, the NRC considers that a 24-month
time schedule would be contrary to the intent of the requirement to
apply the latest edition of the ASME OM Code that is published every 24
months because it could result in licensees applying an outdated
edition in the initial 120-month IST interval. Therefore, the NRC
proposes to extend the time schedule to satisfy the latest edition and
addenda of the ASME OM Code from the current 12 months to 18 months for
the initial 120-month IST interval.
10 CFR 50.55a(f)(4)(ii): Applicable IST Code: Successive 120-Month
Intervals
As discussed in the previous section, several stakeholders
submitted public comments on the Sec. 50.55a 2009-2013 proposed rule,
requesting that the time schedule for complying with the latest ASME
Code edition in Sec. 50.55a(f)(4)(ii) and (g)(4)(ii) for the IST and
ISI programs, respectively, be relaxed from the current time period of
12 months to a new time period of 24 months prior to the applicable
milestones in those paragraphs. The ASME reiterated this request during
an NRC/ASME management public teleconference that was held on March 16,
2016. During that teleconference, ASME discussed the challenges
associated with meeting the 12-month time schedule in order to submit
timely relief or alternative requests for NRC review. These comments
were outside the scope of the proposed Sec. 50.55a ASME 2009-2013
rule. However, the NRC staff indicated that the proposed change would
be considered for a future rulemaking. In evaluating the proposed
change, the NRC has determined that the primary benefit from the
relaxation of this Sec. 50.55a(f)(4)(ii) requirement is that licensees
of nuclear power plants will have more time to update their successive
IST programs and procedures, and to prepare any proposed relief or
alternative requests to the applicable edition of the ASME OM Code. In
addition, licensees of each nuclear power plant will not need to review
ASME OM Code editions incorporated by reference in Sec. 50.55a after
the relaxed 18-month time period before the start of the IST program
interval compared to the 12-month time period required by the current
regulations. In preparing this proposed rule, the NRC has determined
that relaxation of the time schedule for satisfying the latest edition
of the ASME OM Code for the successive 120-month IST interval to be
appropriate. However, the NRC considers that a 24-month time schedule
would be contrary to the intent of the requirement to apply the latest
edition of the ASME OM Code that is published every 24 months.
Therefore, the NRC proposes to extend the time schedule to satisfy the
latest edition and addenda of the ASME OM Code from the current 12
months to 18 months for successive 120-month IST intervals.
10 CFR 50.55a(f)(7), Inservice Testing Reporting Requirements
The NRC proposes to add Sec. 50.55a(f)(7) to require nuclear power
plant applicants and licensees to submit their IST Plans and interim
IST Plan updates related to pumps and valves, and IST Plans and interim
Plan updates related to snubber examination and testing to NRC
Headquarters, the appropriate NRC Regional Office, and the appropriate
NRC Resident Inspector.
The ASME OM Code states in paragraph (a) of ISTA-3200,
``Administrative Requirements,'' that IST Plans shall be filed with the
regulatory authorities having jurisdiction at the plant site. However,
the ASME is planning to remove this provision from the ASME OM Code in
a future edition because this provision is more appropriate as a
regulatory requirement rather than a Code requirement. This change is
being proposed in this rulemaking rather than in a future rulemaking to
ensure that there will not be a period of time when this requirement is
not in effect. The NRC staff needs these IST Plans for use in
evaluating relief and alternative requests, and deferral of quarterly
testing to cold shutdowns and refueling outages. Therefore proposed
condition is an administrative change that would
[[Page 56173]]
relocate the provision from the ASME OM Code to Sec. 50.55a.
10 CFR 50.55a(g)(4)(i): Applicable ISI Code: Initial 120-Month Interval
The NRC proposes to amend Sec. 50.55a(g)(4)(i) to relax the time
schedule for complying with the latest edition of the ASME BPV Code for
the initial 120-month ISI program interval, respectively, from 12
months to 18 months. The basis for the relaxation of the time schedule
discussed previously for the requirement in Sec. 50.55a(f)(4)(i) to
comply with the latest edition and addenda of ASME Section XI Code for
the initial 120-month ISI program is also applicable to the relaxation
of the time period for complying with the latest edition and addenda of
the ASME BPV Code for the initial 120-month ISI program.
10 CFR 50.55a(g)(4)(ii): Applicable ISI Code: Successive 120-Month
Intervals
The NRC proposes to amend Sec. 50.55a(g)(4)(ii) to relax the time
schedule for complying with the latest edition and addenda of the ASME
BPV Code for the successive 120-month ISI program intervals,
respectively, from 12 months to 18 months. The basis for the relaxation
of the time schedule discussed above for the requirement in Sec.
50.55a(f)(4)(ii) to comply with the latest edition and addenda of the
ASME Section XI Code for the successive 120-month ISI programs is also
applicable to the relaxation of the time period for complying with the
latest edition and addenda of the ASME BPV Code for the successive 120-
month ISI programs. The NRC is proposing to amend the regulation in
Sec. 50.55a(g)(4)(ii) to provide up to an 18 month period for
licensees to update their Appendix VIII program for those licensees
whose ISI interval commences during the 12 through 18-month period
after the effective date of this rule.
10 CFR 50.55a(g)(6)(ii)(C): Augmented ISI Requirements: Implementation
of Appendix VIII to Section XI
The NRC proposes to remove the language found in Sec.
50.55a(g)(6)(ii)(C) from the current regulations. This paragraph
describes requirements for initial implementation of older supplements
in ASME BPV Code, Section XI Appendix VIII. Because the implementation
dates have passed, and because licensees are no longer using these
older editions and addenda of the Code that are referenced in this
paragraph, the NRC proposes to remove the condition.
ASME BPV Code Case N-729-6
On September 10, 2008, the NRC issued a final rule to update Sec.
50.55a to incorporate by reference the 2004 Edition of the ASME BPV
Code (73 FR 52730). As part of the final rule, Sec.
50.55a(g)(6)(ii)(D) implemented an augmented inservice inspection
program for the examination of RPV upper head penetration nozzles and
associated partial penetration welds. The program required the
implementation of ASME BPV Code Case N-729-1, with certain conditions.
The application of ASME BPV Code Case N-729-1 was necessary because
the inspections required by the 2004 Edition of the ASME BPV Code,
Section XI were not written to address degradation caused by primary
water stress corrosion cracking (PWSCC) of the RPV upper head
penetration nozzles and associated welds. The safety consequences of
inadequate inspections of the subject nozzles can be significant. The
NRC's determination that the ASME BPV Code-required inspections are
inadequate is based upon operating experience and analysis, because
nickel-based Alloy 600/82/182 material in the RPV head penetration
nozzles and associated welds are susceptible to PWSCC. The absence of
an effective inspection regime could, over time, result in unacceptable
circumferential cracking, or the degradation of the RPV upper head or
other reactor coolant system components by leakage-assisted corrosion.
These degradation mechanisms increase the probability of a loss-of-
coolant accident.
Examination frequencies and methods for RPV upper head penetration
nozzles and welds are provided in ASME BPV Code Case N-729-1. The use
of code cases is voluntary, so these provisions were developed, in
part, with the expectation that the NRC would incorporate the code case
by reference into Sec. 50.55a. Therefore, the NRC adopted rule
language in Sec. 50.55a(g)(6)(ii)(D), requiring implementation of ASME
BPV Code Case N-729-1, with conditions, in order to enhance the
examination requirements in the ASME BPV Code, Section XI for RPV upper
head penetration nozzles and welds. The examinations conducted in
accordance with ASME BPV Code Case N-729-1 provide reasonable assurance
that ASME BPV Code allowable limits will not be exceeded and that PWSCC
will not lead to failure of the RPV upper head penetration nozzles or
welds. However, the NRC concluded that certain conditions were needed
in implementing the examinations in ASME BPV Code Case N-729-1. These
conditions are set forth in Sec. 50.55a(g)(6)(ii)(D).
On March 3, 2016, the ASME approved the sixth revision of ASME BPV
Code Case N-729, (N-729-6). This revision changed certain requirements
based on a consensus review of the inspection techniques and
frequencies. These changes were deemed necessary by the ASME to
supersede the previous requirements under previous versions of N-729 to
establish an effective long-term inspection program for the RPV upper
head penetration nozzles and associated welds in PWRs. The major
changes in the latest revisions are the inclusion of peening mitigation
and extending the replaced head volumetric inspection frequency. Other
minor changes were also made to address editorial issues and to clarify
the code case requirements.
The NRC proposes to update the requirements of Sec.
50.55a(g)(6)(ii)(D) to require licensees of PWRs to implement ASME BPV
Code Case N-729-6, with certain conditions. The NRC conditions have
been modified to address the changes in ASME BPV Code Case N-729-6 from
the latest NRC-approved ASME Code Case N-729 revision in Sec.
50.55a(g)(6)(ii)(D), revision 4, (N-729-4). The NRC's revisions to the
conditions on ASME BPV Code Case N-729-4 that support the
implementation of N-729-6 are discussed in the next sections.
10 CFR 50.55a(g)(6)(ii)(D) Augmented ISI Requirements: Reactor Vessel
Head Inspections
The NRC proposes to revise the paragraphs in Sec.
50.55a(g)(6)(ii)(D) as summarized in the following discussions, which
identify the changes in requirements associated with the proposed
update from ASME BPV Code Case N-729-4 to N-729-6. The major changes in
the code case revision allowing peening as a mitigation method and
extend the PWSCC-resistant RPV upper head inspection frequency from 10
years to 20 years. Additionally, the code case revision changed the
volumetric inspection requirement for plants with previous indications
of PWSCC and allowed the use of the similarities in sister plants to
extend inspection intervals. The NRC is not able to fully endorse these
two new items, therefore the NRC is proposing new conditions. The NRC
has determined that one previous condition restricting the use of
Appendix I of the code case could be relaxed. Further, the code case
deadline for baseline examinations of February 10, 2008 is well in the
past, therefore the NRC is
[[Page 56174]]
proposing a condition that would ensure new plants can perform baseline
examinations without the need for an alternative to these requirements
under Sec. 50.55a(z). Finally, the NRC is proposing to add a condition
that would allow other licensees to use a volumetric leak path
assessment in lieu of a surface examination.
10 CFR 50.55a(g)(6)(ii)(D)(1) Implementation
The NRC proposes to revise Sec. 50.55a(g)(6)(ii)(D)(1) to change
the version of ASME BPV Code Case N-729 from N-729-4 to N-729-6 for the
reasons previously set forth. Due to the incorporation of N-729-6, the
date to establish applicability for licensed PWRs will be changed to
anytime within one year of the effective date of the final rule. This
is to allow some flexibility for licensees to implement the
requirements. No new inspections are required, therefore this allows
licensees to phase in the new program consistent with their needs and
outage schedules. The NRC is also including wording to allow licensee's
previous NRC-approved alternatives to remain valid. The NRC has
completed a review of the currently effective proposed alternatives and
finds that each effective proposed alternative can remain effective
through the update from ASME Code Case N-729-4 to N-729-6 with the
proposed NRC conditions.
10 CFR 50.55a(g)(6)(ii)(D)(2) Appendix I Use
The NRC proposes to revise Sec. 50.55a(g)(6)(ii)(D)(2). The NRC
has determined that the current condition, that the use of Appendix I
is not permitted, is no longer necessary. However the NRC is proposing
a new condition that the analyses required by the code case for missed
coverage both above and below the J groove weld include the analysis
described in I-3000. The NRC's basis for revising the condition is
that, based on its reviews of alternatives proposed by licensees
related to this issue, over a period in excess of 10 years, it has
become apparent to the NRC staff that the I-3000 method produces
satisfactory results and is correctly performed by licensees. The NRC
also notes that the probabilistic approach has not been proposed by
licensees and that it has not been evaluated (including the acceptance
criteria) by the NRC.
The NRC staff finds the proposed change to the condition will have
minimal impact on safety, while minimizing the regulatory burden of NRC
review and approval of a standardized method to provide reasonable
assurance of structural integrity of a reduced inspection area.
10 CFR 50.55a(g)(6)(ii)(D)(4) Surface Exam Acceptance Criteria
The NRC proposes to revise Sec. 50.55a(g)(6)(ii)(D), the current
condition on surface examination acceptance criteria, to update the
ASME BPV Code Case reference. The NRC proposes to modify the condition
Sec. 50.55a(g)(6)(ii)(D)(4) by changing the referenced version of the
applicable ASME BPV Code Case N-729 from N 729-4 to N-729-6.
10 CFR 50.55a(g)(6)(ii)(D)(5) Peening
The NRC proposes to add a new condition that will allow licensees
to obtain inspection relief for peening of their RPV upper heads in
accordance with the latest NRC-approved requirements, contained in
Electric Power Research Institute (EPRI), Materials Reliability Project
(MRP) Topical Report, ``Materials Reliability Program: Topical Report
for Primary Water Stress Corrosion Cracking Mitigation by Surface
Stress Improvement,'' (MRP-335, Revision 3-A) (ADAMS Accession No.
ML16319A282). This document provides guidelines for the NRC-approved
performance criteria, qualification requirements, inspection frequency,
and scope. A licensee may peen any component in accordance with the
requirements and limitations of the ASME Code. However, in order to
obtain NRC-approved inspection relief for a RPV head mitigated with
peening, as described in MRP-335, Revision 3-A, this proposed condition
establishes MRP-335, Revision 3-A as the requirement for performance
criteria, qualifications and inspections. Otherwise the requirements of
an unmitigated RPV upper head inspection program shall apply.
As part of this proposed condition, the NRC is removing two of the
requirements contained in MRP-335, Revision 3-A: (1) The submission of
a plant-specific alternative to the code case will not be required; and
(2) Condition 5.4 will not be required.
Hence, the NRC's proposed condition combines the use of the latest
NRC-accepted performance criteria, qualification and inspection
requirements in MRP-335, Revision 3-A, would allow licensees to not
have to submit a plant-specific proposed alternative to adopt the
inspection frequency of peened RPV head penetration nozzles in MRP-335,
Revision 3-A, and does not require licensees to adhere to NRC Condition
5.4 of MRP-335, Revision 3-A. By combining these points in the proposed
condition, it alleviates the need to highlight nine areas in N-729-6
that do not conform to the current NRC-approved requirements for
inspection relief provided in MRP-335, Revision 3-A.
Because the NRC proposes to require MRP-335, Revision 3-A, within
this proposed condition on the requirements in the ASME Code Case, the
NRC is incorporating by reference MRP-335, Revision 3-A, into Sec.
50.55a(a)(4)(i).
10 CFR 50.55a(g)(6)(ii)(D)(6) Baseline Examinations
The NRC proposes to add a new condition to address baseline
examinations. Note 7(c) of Table 1 of ASME BPV Code Case N-729-6
requires baseline volumetric and surface examinations for plants with
an RPV upper head with less than 8 effective degradation years (EDY) by
no later than February 10, 2008. This requirement has been in place
since ASME BPV Code Case N-729-1 was first required by this section,
and it was a carryover requirement from the First Revised NRC Order EA-
03-009. However, since any new RPV upper head replacements would occur
after 2008, this requirement can no longer be met. While it is not
expected that a new head using A600 nozzles would be installed, the NRC
is conditioning this section to prevent the need for a licensee to
submit a proposed alternative for such an event, should it occur. The
NRC proposed condition would instead require a licensee to perform a
baseline volumetric and surface examination within 2.25 reinspection
years not to exceed 8 calendar years, as required under N-729-6, Table
1 for the regular interval of inspection frequency.
10 CFR 50.55a(g)(6)(ii)(D)(7) Sister Plants
The NRC proposes to add a new condition to address the use of the
term sister plants for the examinations of RPV upper heads. The use of
``sister plants'' under ASME BPV Code Case N-729-6 would allow
extension of the volumetric inspection of replaced RPV heads with
resistant materials from the current 10-year inspection frequency to a
period of up to 40 years.
As part of mandating the use of ASME BPV Code Case N-729-6 in this
proposed rule, the NRC is approving the ASME Code's extension of the
volumetric inspection frequency from every 10 years to every 20 years.
The NRC finds that the documents, ``Technical Basis for Reexamination
Interval Extension for Alloy 690 PWR Reactor Vessel Top Head
Penetration
[[Page 56175]]
Nozzles (MRP-375)'' and improvement factors ``Recommended Factors of
Improvement for Evaluating Primary Water Stress Corrosion Cracking
(PWSCC) Growth Rates of Thick-Wall Alloy 690 Materials and Alloy 52,
152, and Variants Welds (MRP-386),'' provide a sound basis for a 20-
year volumetric inspection interval and a 5-year bare metal visual
inspection interval for alloy 690/52/152 materials subject to this code
case thereby providing reasonable assurance of the structural integrity
of the RPV heads.
However, at the present time, the NRC is proposing a condition to
prohibit the concept of ``sister plants''. If used, this concept would
increase the inspection interval for plants with sisters from 20 years
to 40 years. The NRC is currently evaluating both the definition of
sister plants and factors of improvement between the growth of PWSCC in
alloys 600/82/182 and 690/52/152.
It is currently unclear to the NRC staff whether the criteria for
sister plants (i.e., same owner) are appropriate criteria. The NRC
staff also questions whether other criteria such as environment, alloy
heat, and numbers of sister plants in a particular group should be
included in the definition.
The NRC staff continues to review information on PWSCC growth rates
and factors of improvement for alloy 690/52/152 and 600/82/182 as
proposed in MRP-386. While the NRC staff has concluded that crack
growth in alloy 690/52/152 is sufficiently slower than in alloy 600/82/
182 to support an inspection interval of 20 years, work continues in
assessing whether the data and analyses support a 40-year interval.
Public comments concerning both the definition of sister plants and
crack growth rate factors of improvement are being solicited during the
comment period of this proposed rule.
10 CFR 50.55a(g)(6)(ii)(D)(8) Volumetric Leak Path
The NRC proposes to add a new condition to substitute a volumetric
leak path assessment for the required surface exam of the partial
penetration weld of Paragraph -3200(b). The NRC finds that the use of a
volumetric leak path assessment is more useful to confirm a possible
leakage condition through the J-groove weld than a surface examination
of the J-groove weld. While a surface examination may detect surface
cracking, it will not confirm that such an indication is a flaw that
caused leakage. A positive volumetric leak path assessment will provide
a clear confirmation of leakage, either through the nozzle, weld or
both. The NRC notes, that since all nozzles have had a volumetric
examination, a baseline volumetric leak path assessment is available
for comparison, and therefore provides additional assurance of
effectiveness of the volumetric leak path assessment technique. As
such, to eliminate the need for potential proposed alternatives
requiring NRC review and authorization, this condition is proposed to
increase regulatory efficiency.
ASME BPV Code Case N-770-5
On June 21, 2011 (76 FR 36232), the NRC issued a final rule
including Sec. 50.55a(g)(6)(ii)(F), requiring the implementation of
ASME BPV Code Case N-770-1, ``Alternative Examination Requirements and
Acceptance Standards for Class 1 PWR Piping and Vessel Nozzle Butt
Welds Fabricated with UNS N06082 or UNS N86182 Weld Filler Material
With or Without Application of Listed Mitigation Activities,'' with
certain conditions. On November 7, 2016, the ASME approved the fifth
revision of ASME BPV Code Case N 770 (N-770-5). The major changes from
N-770-2, the last revision to be mandated by Sec. 50.55a(g)(6)(ii)(F),
to N-770-5 included extending the inspection frequency for cold leg
temperature dissimilar metal butt welds greater than 14-inches in
diameter to once per inspection interval not to exceed 13 years,
performance criteria and inspections for peening mitigated welds, and
inservice inspection requirements for excavate and weld repair
mitigations. Minor changes were also made to address editorial issues,
to correct figures, or to add clarity. The NRC finds that the updates
and improvements in N-770-5 are sufficient to update Sec.
50.55a(g)(6)(ii)(F).
The NRC, therefore, is updating the requirements of Sec.
50.55a(g)(6)(ii)(F) to require licensees to implement ASME BPV Code
Case N-770-5, with conditions. The previous NRC conditions have been
modified to address the changes in ASME BPV Code Case N-770-5 and to
ensure that this regulatory framework will provide adequate protection
of public health and safety. The following sections discuss each of the
NRC's revisions to the conditions on ASME BPV Code Case N-770-2 that
support the implementation of N-770-5.
10 CFR 50.55a(g)(6)(ii)(F)(1) Augmented ISI Requirements: Examination
Requirements for Class 1 Piping and Nozzle Dissimilar-Metal Butt
Welds--(1) Implementation
The NRC proposes to revise this condition to mandate the use of
ASME BPV Code Case N-770-5, as conditioned by this section, in lieu of
the current requirement to mandate ASME BPV Code Case N-770-2. The
wording of this condition will allow a licensee to adopt this change
anytime during the first year after the publication of the final rule.
This is to provide flexibility for a licensee to adapt to the new
requirements. Finally, included in this provision is an allowance for
all previous NRC-approved licensee's alternatives to the requirements
of this section to remain valid, regardless of the version of ASME BPV
Code Case N-770 they were written against. The NRC has reviewed all
currently applicable licensee alternatives to this code case and has
found that the change from Code Case N-770-2 to N-770-5 required by
this proposed regulation neither invalidates nor degrades plant safety
associated with the continued use of existing alternatives. Therefore,
to provide regulatory efficiency, the NRC finds that all previous NRC-
approved alternatives will remain valid for their specifically NRC-
approved duration of applicability.
10 CFR 50.55a(g)(6)(ii)(F)(2) Categorization
The NRC proposes to revise this condition to include the
categorization of welds mitigated by peening. This condition currently
addresses the categorization for inspection of unmitigated welds and
welds mitigated by various processes.
The new section, to this revised condition, is to categorize
dissimilar metal butt welds mitigated by peening. ``Topical Report for
Primary Water Stress Corrosion Cracking Mitigation by Surface Stress
Improvement,'' MRP-335, is the technical basis summary document for the
application of peening in upper heads and dissimilar metal butt welds
to address primary water stress corrosion cracking. The NRC conducted a
comprehensive review of this document for generic application. The
requirements contained in the NRC-approved version of this report, MRP-
335, Revision 3-A differ in several respects from the requirements
contained in ASME BPV Code Case N-770-5. As such, to avoid confusion
with multiple conditions, the NRC proposes to accept categorization of
welds as being mitigated by peening, if said peening follows the
performance criteria, qualification requirements, and inspection
guidelines of MRP-335, Revision 3-A. Once implemented, the inspection
guidelines of MRP-335, Revision 3-A would provide inspection relief
from the requirements of an unmitigated dissimilar metal butt weld.
[[Page 56176]]
As part of this proposed condition, the NRC is removing the need for
the licensee to submit a plant-specific proposed alternative to
implement the inspection relief in accordance with MRP-335, Revision 3-
A.
Because MRP-335, Revision 3-A, is being proposed to be used as a
condition against the requirements in the ASME Code Case, the NRC is
incorporating by reference MRP-335, Revision 3-A, into Sec.
50.55a(a)(4)(i).
The requirements for categorization of all other mitigated or non-
mitigated welds remain the same.
As noted previously, all of these requirements, except for the
categorization of peening, were in the previous conditions for mandated
use of ASME BPV Code Cases N-770-2 and N-770-1.
10 CFR 50.55a(g)(6)(ii)(F)(3) Baseline Examinations
The NRC proposes to delete this condition. The current condition
regarding baseline inspections was considered unnecessary, as all
baseline volumetric examinations are expected to have been completed.
If a baseline examination is required, the licensee can follow the
examination requirements in ASME BPV Code Case N-770-5. This condition
number is reserved, to maintain the NRC condition numbering from the
past rulemaking, and in this way, limit the need for additional updates
to current procedures and documentation, when no substantive change has
occurred.
10 CFR 50.55a(g)(6)(ii)(F)(4) Examination Coverage
The NRC proposes to revise this condition to make an editorial
change to update the reference to ASME BPV Code Case N-770-2 to N-770-
5.
10 CFR 50.55a(g)(6)(ii)(F)(6) Reporting Requirements
The NRC proposes to revise this condition to address the deletion
of wording in Paragraph -3132.3(d) of ASME BPV Code Case N-770-5 and
relax the requirement for submitting the summary report to the NRC. The
purpose of this condition is to obtain timely notification of
unanticipated flaw growth in a mitigated butt weld in the reactor
coolant pressure boundary. While NRC onsite and regional inspectors
provide a plant-specific role in assessing the current safe operation
of a specific plant, the NRC staff in the Office of Nuclear Reactor
Regulation is also responsible for assessing the generic impact of the
potential reduced effectiveness of a mitigation technique across the
fleet. In order to address these concerns, the NRC has found that, in
the event that a dissimilar metal butt weld is degraded, it is
necessary for the NRC staff to obtain timely notification of the flaw
growth and a report summarizing the evaluation, along with inputs,
methodologies, assumptions, and causes of the new flaw or flaw growth
within 30 days of the plant's return to service. This is a relaxation
from the previous requirement to provide a report prior to entering
mode 4 prior to plant startup. In its review of the prior condition,
the NRC has determined that the burden associated with the submission
of a report prior to entry into mode 4 exceeded the immediate safety
benefit from the report. The NRC also has determined that a timely
notification regarding the event was sufficient to begin the
determination of whether an immediate generic safety concern exists.
Further, the NRC has found the submittal of a report within 30 days is
both necessary and sufficient to allow for the evaluation of any long-
term impacts of the flaw growth on the overall inspection programs for
that specific mitigation type.
The NRC has found that the deletion of the following sentence from
Paragraph -3132.3(d), ``Any indication in the weld overlay material
characterized as stress corrosion cracking is unacceptable,'' did not
have a sufficiently identified technical basis to support its removal.
Given that the NRC's approval of weld overlays is based on the
resistance of the overlay material to cracking, any flaw growth into
this material should call into question the effectiveness of that
specific mitigation method. However, the NRC recognizes that there
could be instances were NDE measurement uncertainty may require a
conservative call on flaw size that may lead to the assumption of flaw
growth. Rather than automatically assume this flaw growth is
unacceptable, as stated in the previous requirement mandated under ASME
BPV Code Case N-770-2, the NRC has found that reasonable assurance of
plant safety could be assured by reporting this condition to the NRC
for evaluation, in accordance with this condition. This relaxation of
the previous requirement allows for regulatory flexibility in assessing
the safety significance of any potential flaw growth.
10 CFR 50.55a(g)(6)(ii)(F)(9) Deferral
The NRC proposes to revise this condition to address the potential
deferrals of volumetric inspections for welds mitigated by peening as
well as for welds mitigated by the excavate and weld technique.
Volumetric inspections performed once per interval or on a ten-year
basis can, in some instances, be deferred to the end of the current
ten-year inservice inspection interval. As such, this could allow an
inspection frequency, which is assumed to be approximately 10 years to
be extended to as much as 20 years. While there are certain conditions
that would warrant such an extension, the NRC finds, in the following
two instances, that allowing such deferrals would provide an
unacceptable reduction in the margin for safety.
For welds peened in accordance with the performance and
qualification criteria of MRP-335, Revision 3-A, the long-term
inservice inspection interval, as required by MRP-335, Revision 3-A
Table 4-1, is once per inspection interval. Note 11 of Table 4-1 would
allow deferral of peened welds beyond the 10-year inspection frequency.
This deferral would be beyond the NRC technical basis of Paragraph
4.6.3 in the NRC Safety Evaluation of MRP-335, Revision 3-A. Therefore,
the NRC proposes to revise this condition to prohibit the deferral of
examinations of peened welds, without the submission of a plant-
specific proposed alternative for NRC review and approval.
For welds mitigated with the excavate and weld repair technique,
specifically inspection items M-2, N-1 and N-2, Note 11 of Table 1 of
ASME BPV Code Case N-770-5 would allow the deferral of the second
inservice examination to the end of the 10-year inservice inspection
interval. The NRC finds the deferral of the second inservice exam
unacceptable. If a weld was mitigated near the end of a 10-year
inservice inspection interval, the first post mitigation examination
might occur at the beginning of the next 10-year inservice inspection
interval. Since the welds are required to be examined once per
interval, the second post mitigation exam would be in the next
interval. Because Note 11 allows the exams to be deferred, in such
cases, it could approach twenty years between the first and second post
mitigation exams. The NRC finds that a requirement to perform a second
post mitigation exam within 10 years of the initial post mitigation
exam to be more consistent with the reinspection timeline for other
mitigations, such as full structural weld overlay and is therefore
acceptable to the NRC. However, the NRC finds that, after the initial
and second post mitigation examinations, provided the examination
volumes show no indications of crack growth or new cracking, allowance
for deferral of examination of these welds, as deemed appropriate, by
the plant owner is
[[Page 56177]]
acceptable. As such, this proposed condition only restricts the
deferral of the second inservice examination.
Given the two new issues identified above, the NRC proposes to
revise NRC Condition Sec. 50.55a (g)(6)(ii)(F)(9) Deferral to prohibit
the deferral of volumetric inspections of welds mitigated by peening
under MRP-335, Revision 3-A and the first 10-year inservice inspection
examination for welds mitigated by the excavate and weld repair
technique, inspection items M-2, N-1 and N-2 only.
10 CFR 50.55a(g)(6)(ii)(F)(10) Examination Technique
The NRC proposes to revise this condition to make an editorial
change to update the reference to ASME BPV Code Case N-770-2 to N-770-
5.
10 CFR 50.55a(g)(6)(ii)(F)(11) Cast Stainless Steel
The NRC proposes to amend Sec. 50.55a(g)(6)(ii)(F)(11) to provide
licensees with an alternative to meeting the current condition. The
alternative would be to use ASME Code Case N-824 when examining
dissimilar metal welds where inspections through a cast austenitic
stainless steel component is required. The existing condition requires
licensees to have a qualified program in place to inspect dissimilar
metal butt welds with CASS materials from the CASS side by 2022. The
NRC recognizes that there is no current Supplement 9 inspection
guideline that would meet this requirement. At an NRC public meeting on
April 17, 2018, the NRC and industry representatives discussed the
estimated number of welds that would be covered by the condition. Given
this information, the NRC has determined that rather than requiring a
full qualification program to be developed within this timeframe, ASME
Code Case N-824 would provide an acceptable alternative and provide
reasonable assurance of public health and safety.
ASME BPV Code Case N-824 incorporates best practices for the
inspection of cast stainless steel from NUREG/CR-7122 and NUREG/CR-
6933. NUREG/CR-7122 showed that pressurizer surge line sized piping
welds may be inspectable with existing dissimilar metal butt weld
inspection procedures. NUREG/CR-6933 showed that large-bore cast
stainless steel may be inspectable using specialized low-frequency
inspection procedures. Therefore, the NRC will modify the condition to
allow the use of ASME Code Case N-824, as conditioned in RG 1.147, as
an option to the development of Appendix VIII, Supplement 9 or similar
qualifications, or, when examining dissimilar metal welds where
inspections through a cast austenitic stainless steel component is
required to obtain volumetric inspection coverage.
10 CFR 50.55a(g)(6)(ii)(F)(13) Encoded Ultrasonic Examination
The NRC proposes to revise this current condition, which requires
the encoded examination of unmitigated and mitigated cracked butt welds
under the scope of ASME BPV Code Case N-770-5. In particular, the
proposed revision is being expanded to address changes in ASME BPV Code
Case N-770-5 to include inspection categories B-1, B-2 for cold leg
welds, which were previously under the single inspection category B,
and the new inspection categories N-1, N-2 and O for cracked welds
mitigated with the excavate and weld repair technique. The inclusion of
these weld categories is in line with the previous basis for this
condition.
Further, the NRC proposes to relax the requirement for 100 percent
of the required inspection volume to be encoded. The new requirement
would allow essentially 100 percent of the required inspection volume
to be encoded under the definition of essentially 100 percent in ASME
BPV Code Case N-460. This code case allows the reduction to 90 percent
coverage only if a physical limitation or impediment to full coverage
is encountered during the inspection. The NRC finds this relaxation
appropriate, given the potential that the physical size of the encoding
equipment may reduce attainable coverage, when compared to manual
techniques. The NRC staff finds that the reduction in safety associated
with this potential minor decrease in coverage is minimal. Adoption of
the revised proposed condition will reduce unnecessary preparation and
submittal of requests for NRC review and approval of alternatives to
this requirement.
10 CFR 50.55a(g)(6)(ii)(F)(14) Excavate and Weld Repair Cold Leg
The NRC proposes to add a new condition to address the initial
inspection of cold leg operating temperature welds after being
mitigated by the excavate and weld repair technique. The excavate and
weld repair technique is a new mitigation category introduced in ASME
BPV Code Case N-770-5. The first inspection requirement for inspection
item M-2, N-1 and N-2 welds, after being mitigated, is during the 1st
or 2nd refueling outages after mitigation. The NRC finds that the ASME
BPV Code Case N-770-5 language does not provide separate inspection
programs between the cold leg and the hot leg temperature for the first
volumetric inspection. The NRC determines that, at hot leg
temperatures, one fuel cycle is sufficient for a preexisting,
nondetectable, crack to grow to detectable size (10 percent through
wall). However, at cold leg temperatures, crack growth is sufficiently
slow that preexisting, undetected, cracks are unlikely to reach
detectable size in a single fuel cycle. Therefore, in order to ensure
the effectiveness of the initial volumetric examination to verify no
unanticipated flaw growth in the mitigated weld prior to extending the
inspection frequency to 10 years or beyond, the NRC proposes to add a
condition to require the first examination to be performed during the
second refueling outage following the mitigation of cold leg operating
temperature welds.
10 CFR 50.55a(g)(6)(ii)(F)(15) Cracked Excavate and Weld Repair
The NRC proposes to add a new condition to address the long-term
inspection frequency of cracked welds mitigated by the excavate and
weld repair technique, i.e. inspection category N-1. The long-term
volumetric inspection frequency for the cracked N-1 welds under ASME
BPV Code Case N-770-5 is a 25 percent sample each 10-year inspection
interval. In comparison, the NRC notes that the long-term volumetric
inspection frequency of a non-cracked weld mitigated with the excavate
and weld repair technique without stress improvement (inspection
category M-2) is 100 percent each 10-year inspection interval. Due to
not attaining surface stress improvement, M-2 welds could potentially
have cracking initiate at any time over the remaining life of the
repair. Therefore, a volumetric inspection frequency of once per 10-
year inspection frequency is warranted to verify weld structural
integrity. However, every N-1 categorized weld already has a pre-
existing crack, but Code Case N-770-5 would allow a 25 percent sample
inspection frequency each 10-year inservice inspection interval. This
could allow some N-1 welds with preexisting flaws to not be
volumetrically inspected for the remainder of plant life. The NRC finds
insufficient technical basis to support the difference in inspection
frequency between N-1 and M-2 welds. Therefore, the NRC proposes a
condition on N-1 inspection category welds that would require the same
long-term inspection frequency, as that determined acceptable by the
ASME BPV Code Case N-770-5 for M-2 welds, i.e., non-cracked 360 degree
excavate
[[Page 56178]]
and weld repair with no stress improvement credited.
10 CFR 50.55a(g)(6)(ii)(F)(16) Partial Arc Excavate and Weld Repair
The NRC proposes to add a new condition to prevent the use of the
inspection criteria for partial arc excavate and weld repair technique
contained in ASME BPV Code Case N-770-5. The NRC staff notes that ASME
BPV Code Case N-847 which describes the process of installing an
excavate and weld repair has not been included in RG 1.147 and has not
been incorporated by reference into Sec. 50.55a. As a result,
licensees must propose an alternative to the ASME Code to make a repair
using the excavate and weld repair technique. Therefore, preventing the
use of the inspection criteria contained in ASME BPV Code Case N-770-5,
proposes no additional burden on the licensee when viewed in light of
the requirement to propose an alternative to the ASME BPV Code to use
the excavate and weld repair technique. The NRC's basis for this
condition is that initial research into stress fields and crack growth
associated with the ends of the repair indicated that the potential for
crack growth rates to exceed those expected in the absence of the
repair. The NRC also notes that there is potential for confusion
regarding the inspection interval for these welds associated with
whether Note 5 can be applied.
IV. Section-by-Section Analysis
Paragraph (a)(1)(i)
This proposed rule would revise paragraph (a)(1)(i) by removing the
abbreviation definition for ASME BPV Code in the first sentence.
Paragraph (a)(1)(i)(E)
This proposed rule would add new paragraphs (a)(1)(i)(E)(18) and
(19) to include the 2015 and 2017 Editions of the ASME BPV Code.
Paragraph (a)(1)(ii)
This proposed rule would revise paragraphs (a)(1)(ii) to remove the
acronym ``BPV'' and replace it with ``Boiler and Pressure Vessel.''
Paragraph (a)(1)(ii)(C)
This proposed rule would revise paragraphs (a)(1)(ii)(C)(52) and
(53) to remove parenthetical language and would add new paragraphs
(a)(1)(ii)(C)(54) and (55) to include the 2015 and 2017 Editions of the
ASME BPV Code.
Paragraph (a)(1)(iii)(C)
This proposed rule would revise the reference from Code Case N-729-
4 to N-729-6.
Paragraph (a)(1)(iii)(D)
This proposed rule would revise the reference from Code Case N-770-
2 to N-770-5.
Paragraph (a)(1)(iv)
This proposed rule would remove parenthetical language from
paragraph (a)(1)(iv).
Paragraph (a)(1)(iv)(C)
This proposed rule would add new paragraphs (a)(1)(iv)(C)(2) and
(3) to include the 2015 and 2017 Editions of the ASME BPV Code.
Paragraph (a)(4)
This proposed rule would add a new paragraph (a)(4) to incorporate
by reference the Electric Power Research Institute, Materials
Reliability Program, 3420 Hillview Avenue, Palo Alto, CA 94304-1338;
telephone: 1-650-855-2000; http://www.epri.com.
Paragraph (a)(4)(i)
This proposed rule would add a new paragraph (a)(4)(i) to
incorporate by reference the Materials Reliability Program: Topical
Report for Primary Water Stress Corrosion Cracking Mitigation by
Surface Stress Improvement (MRP-335, Revision 3-A), EPRI approval date:
November 2016. Paragraph (a)(4)(ii) would be added and resereved.
Paragraph (b)(1)
This proposed rule would change the reference from the 2013 to the
2017 Edition of the ASME BPV Code.
Paragraph (b)(1)(ii)
This proposed rule would change the word ``Note'' to ``Footnote''
in Table 1 of paragraph (b)(1)(ii) and revise the last reference in the
table from the 2013 Edition to the 2017 Edition of the ASME BPV Code.
Paragraph (b)(1)(iii)
This proposed rule would change the references from the 2008
Addenda to the 2017 Edition of the ASME BPV Code.
Paragraph (b)(1)(v)
This proposed rule would revise paragraph (b)(1)(v) to limit the
condition so that it applies only for the 1995 Edition through the
2009b Addenda of the 2007 Edition, where the NQA-1-1994 Edition is
incorporated by reference in paragraph (a)(1) of this section.
Paragraph (b)(1)(vi)
This proposed rule would revise paragraph (b)(1)(vi) to replace
``the latest edition and addenda'' with ``all editions and addenda up
to and including the 2013 Edition.''
Paragraph (b)(1)(vii)
This proposed rule would revise paragraph (b)(1)(vii) to replace
``the 2013 Edition'' with ``all editions and addenda up to and
including the 2017 Edition.''
Paragraph (b)(1)(x)
This proposed rule would add new paragraph (b)(1)(x) and its
subparagraphs (A) and (B) to include two conditions necessary to
maintain adequate standards for visual examinations of bolts, studs,
and nuts.
Paragraph (b)(1)(xi)
This proposed rule would add new paragraph (b)(1)(xi) and its
subparagraphs (A) through (E) to include five conditions that are
necessary to install safety-related Class 3 HDPE pressure piping in
accordance with ASME BPV Code, Section III, Mandatory Appendix XXVI.
The first two conditions apply to the 2015 and 2017 Editions of Section
III. The third, fourth, and fifth conditions apply only to the 2017
Edition of Section III.
Paragraph (b)(1)(xii)
This proposed rule would add new paragraph (b)(1)(xii) which
applies to the use of certifying engineers.
Paragraph (b)(2)
This proposed rule would revise paragraph (b)(2) to change the
reference from the 2013 Edition to the 2017 Edition of the ASME BPV
Code.
Paragraph (b)(2)(vi)
This proposed rule would remove and reserve paragraph (b)(2)(vi).
Paragraph (b)(2)(vii)
This proposed rule would remove and reserve paragraph (b)(2)(vii).
Paragraph (b)(2)(ix)
This proposed rule would revise paragraph (b)(2)(ix) to add
references to new paragraph (b)(2)(ix)(K) of this section, where
applicable. It would also replace ``the latest edition and addenda''
with ``the 2015 Edition.''
Paragraph (b)(2)(ix)(K)
This proposed rule would add new paragraph (b)(2)(ix)(K) to require
visual examination of the moisture barrier materials installed in
containment leak chase channel system closures at
[[Page 56179]]
concrete floor interfaces. This condition will be applicable to all
editions and addenda of Section XI, Subsection IWE, of the ASME BPV
Code, prior to the 2017 Edition, that are incorporated by reference in
paragraph (b) of this section.
Paragraph (b)(2)(xvii)
This proposed rule would remove and reserve paragraph (b)(2)(xvii).
Paragraph (b)(2)(xviii)(D)
This proposed rule would revise paragraph (b)(2)(xviii)(D) to
extend the applicability to users of the latest edition incorporated by
reference in paragraph (a)(1)(ii) of this section.
Paragraph (b)(2)(xx)(B)
This proposed rule would revise paragraph (b)(2)(xx)(B) to clarify
the NRC's expectations for system leakage tests performed in lieu of a
hydrostatic pressure test, following repair/replacement activities
performed by welding or brazing on a pressure retaining boundary using
the 2003 Addenda through the latest edition and addenda of ASME BPV
Code, Section XI incorporated by reference in paragraph (a)(1)(ii) of
this section.
Paragraph (b)(2)(xx)(C)
This proposed rule would add new paragraph (b)(2)(xx)(C) and
subparagraphs (1) and (2) to include two conditions on the use of the
alternative BWR Class 1 system leakage test described in IWA-
5213(b)(2), IWB-5210(c) and IWB-5221(d) of the 2017 Edition of ASME BPV
Code, Section XI.
Paragraph (b)(2)(xxi)(A)
This proposed rule would remove and reserve paragraph
(b)(2)(xxi)(A).
Paragraph (b)(2)(xxi)(B)
This proposed rule would add new paragraph (b)(2)(xxi)(B) and its
subparagraphs (1) through (3) that will include conditions on the use
of the provisions of IWB-2500(f) and (g) and Notes 6 and 7 of Table
IWB-2500-1 of the 2017 Edition of ASME BPV Code, Section XI.
Paragraph (b)(2)(xxv)
This proposed rule would revise paragraph (b)(2)(xxv) introductory
text and add new subparagraphs (A) and (B) that would prohibit the use
of IWA-4340 in Section XI editions and addenda earlier than the 2011
Edition and would allow the use of IWA-4340 in addenda and editions
from the 2011 Addenda through the latest edition incorporated by
reference in this section under certain conditions.
Paragraph (b)(2)(xxvi)
This proposed rule would revise paragraph (b)(2)(xxvi) to clarify
the NRC's expectations for pressure testing of ASME BPV Code Class 1,
2, and 3 mechanical joints disassembled and reassembled during the
performance of an ASME BPV Code, Section XI activity.
Paragraph (b)(2)(xxxii)
This proposed rule would revise the reporting requirements in
paragraph (b)(2)(xxxii).
Paragraph (b)(2)(xxxiv)
This proposed rule would revise paragraph (b)(2)(xxxiv) and its
subparagraph (B) to extend the applicability from the 2013 Edition
through the latest edition incorporated by reference in paragraph
(a)(1)(ii) of this section.
Paragraph (b)(2)(xxxv)
This proposed rule would revise paragraph (b)(2)(xxxv) to designate
the introductory text of paragraph (b)(2)(xxxv) minus the paragraph
heading as subparagraph (A) and it would also add new subparagraph (B).
Paragraph (b)(2)(xxxvi)
This proposed rule would revise the condition in paragraph
(b)(2)(xxxvi) to also include the use of the 2015 and 2017 Editions of
ASME BPV Code, Section XI.
Paragraph (b)(2)(xxxviii)
This proposed rule would add new paragraph (b)(2)(xxxviii) and its
subparagraphs (A) and (B) that contain two conditions on the use of
ASME BPV Code, Section XI, Appendix III, Supplement 2.
Paragraph (b)(2)(xxxix)
This proposed rule would add new paragraph (b)(2)(xxxix) and its
subparagraphs (A) and (B) that contain conditions on the use of IWA-
4421(c)(1) and IWA-4421(c)(2) of Section XI, in the 2017 Edition.
Paragraph (b)(2)(xl)
This proposed rule would add new paragraph (b)(2)(xl) to include
the requirements for the prohibitions on the use of IWB-3510.4(b).
Paragraph (b)(2)(xli)
This proposed rule would add new paragraph (b)(2)(xli) to include
the requirements for the prohibitions on the use of IWB-3112(a)(3) and
IWC-3112(a).
Paragraph (b)(2)(xlii)
This proposed rule would add new paragraph (b)(2)(xlii) to include
the requirements for the use of the provisions in Table IWB-2500-1,
Examination Category B-F, Pressure Retaining Dissimilar Metal Welds in
Vessel Nozzles, Item B5.11 and Item B5.71.
Paragraph (b)(3)
This proposed rule would revise paragraph (b)(3) to include
Appendix IV in the list of Mandatory Appendices and it would also
remove the reference to the ``2012 Edition'' and replace it with ``the
latest edition and addenda of the ASME OM Code incorporated by
reference.'' It would also revise the last sentence in the paragraph
for clarity.
Paragraph (b)(3)(ii)
This proposed rule would revise paragraph (b)(3)(ii) to remove the
reference to the ``2011 Addenda, and 2012 Edition'' and replace it with
``the latest edition and addenda of the ASME OM Code incorporated by
reference in paragraph (a)(1)(iv) of this section.''
Paragraph (b)(3)(iv)
This proposed rule would revise paragraph (b)(3)(iv) to update the
conditions for use of Appendix II of the ASME OM Code, 2003 Addenda
through the 2015 Edition.
Paragraph (b)(3)(viii)
This proposed rule would revise paragraph (b)(3)(viii) to remove
the reference to the ``2011 Addenda, or 2012 Edition'' and replace it
with ``the latest edition and addenda of the ASME OM Code incorporated
by reference in paragraph (a)(1)(iv) of this section.''
Paragraph (b)(3)(ix)
This proposed rule would revise paragraph (b)(3)(ix) to update the
conditions for use of Subsection ISTF of the ASME OM Code, through the
2012 Edition or 2015 Edition.
Paragraph (b)(3)(xi)
This proposed rule would revise paragraph (b)(3)(xi) to extend the
applicability of the reference to the ASME OM Code, 2012 Edition
through the latest edition and addenda of the ASME OM Code incorporated
by reference in paragraph (a)(1)(iv). It would also provide additional
clarity regarding obturator positions for valves with remote position
indication.
Paragraph (b)(3)(xii)
This proposed rule would add a new paragraph (b)(3)(xii) for air-
operated valves (Appendix IV).
Paragraphs (f)(4)(i) and (ii)
This proposed rule would revise paragraphs (f)(4)(i) and (ii) to
change the
[[Page 56180]]
time frame for complying with the latest edition and addenda of the
ASME OM Code from 12 months to 18 months, both for the initial and
successive IST programs.
Paragraph (f)(7)
This proposed rule would add new paragraph (f)(7) to include the
requirements for inservice testing reporting.
Paragraph (g)(4)
This proposed rule would revise paragraph (g)(4) to remove the
phrase ``subject to the condition referenced in paragraph (b)(2)(vi) of
this section.''
Paragraph (g)(4)(i)
This proposed rule would revise paragraph (g)(4)(i) to change the
time frame for complying with the latest edition and addenda of the
ASME BPV Codes, from 12 months to 18 months, for ISI programs.
Paragraph (g)(4)(ii)
This proposed rule would revise paragraph (g)(4)(ii) to change the
time frames for complying with the latest edition and addenda of the
ASME BPV Codes, from 12 months to 18 months, for successive ISI
programs. It also would remove the date of August 17, 2017, and replace
that date with the effective date of the final rule.
Paragraph (g)(6)(ii)(C)
This proposed rule would remove and reserve paragraph
(g)(6)(ii)(C).
Paragraph (g)(6)(ii)(D)(1)
This proposed rule would revise paragraph (g)(6)(ii)(D)(1) to
remove the date of August 17, 2017, and replace that date with the
effective date of the final rule. It would also update the reference
from Code Case N-729-4 to Code Case N-729-6. It would also be revised
to include the conditions in paragraphs (2) through (8) and that
licensees must be in compliance with these conditions by no later than
1 year from the effective date of the final rule.
Paragraph (g)(6)(ii)(D)(2)
This proposed rule would revise paragraph (g)(6)(ii)(D)(2) in its
entirety.
Paragraph (g)(6)(ii)(D)(4)
This proposed rule would revise paragraph (g)(6)(ii)(D)(4) to
update the reference to ASME BPV Code Case N-729 from revision 4 to
revision 6.
Paragraphs (g)(6)(ii)(D)(5) through (8)
This proposed rule would add new paragraphs (g)(6)(ii)(D)(5)
through (8) to include the requirements for peening, baseline
examinations, sister plants, and volumetric leak path.
Paragraph (g)(6)(ii)(F)(1)
This proposed rule would revise paragraph (g)(6)(ii)(F)(1) to
remove the date of August 17, 2017, and replace that date with the
effective date of the final rule. It would also update the reference
from Code Case N-770-2 (revision 2) to Code Case N-770-5 (revision 5).
It would also be revised to include the conditions in paragraphs
(g)(6)(ii)(F)(2) through (16) of this section and that licensees must
be in compliance with these conditions by no later than 1 year from the
effective date of the final rule.
Paragraph (g)(6)(ii)(F)(2)
This proposed rule would revise paragraph (g)(6)(ii)(F)(2) to
include subparagraphs (i) through (v).
Paragraph (g)(6)(ii)(F)(3)
This proposed rule would remove and reserve paragraph
(g)(6)(ii)(F)(3).
Paragraph (g)(6)(ii)(F)(4)
This proposed rule would revise paragraph (g)(6)(ii)(F)(4) to
change the reference from ASME BPV Code Case N-770-2 (revision 2) to
Code Case N-770-5 (revision 5).
Paragraph (g)(6)(ii)(F)(6)
This proposed rule would revise paragraph (g)(6)(ii)(F)(6) to
provide greater clarity of the requirements that must be met.
Paragraph (g)(6)(ii)(F)(9)
This proposed rule would revise paragraph (g)(6)(ii)(F)(9) to
include subparagraphs (i) through (iii).
Paragraph (g)(6)(ii)(F)(10)
This proposed rule would revise paragraph (g)(6)(ii)(F)(10) from
ASME BPV Code Case N-770-2 (revision 2) to N-770-5 (revision 5).
Paragraph (g)(6)(ii)(F)(11)
This proposed rule would revise paragraph (g)(6)(ii)(F)(11) to
include an alternative to meeting the current condition.
Paragraph (g)(6)(ii)(F)(13)
This proposed rule would revise paragraph (g)(6)(ii)(F)(13) to
include inspection categories B-1, B-2, N-1, N-2 and O.
Paragraph (g)(6)(ii)(F)(14) through (16)
This proposed rule would add new paragraphs (g)(6)(ii)(F)(14)
through (16) to contain the new requirements: Excavate and weld repair
cold leg, cracked excavate and weld repair, and partial arc excavate
and weld repair.
V. Generic Aging Lessons Learned Report
Background
In December 2010, the NRC issued ``Generic Aging Lessons Learned
(GALL) Report,'' NUREG-1801, Revision 2 (ADAMS Accession No.
ML103490041), for applicants to use in preparing license renewal
applications. The GALL report provides aging management programs (AMPs)
that the NRC has concluded are sufficient for aging management in
accordance with the license renewal rule, as required in Sec.
54.21(a)(3). In addition, ``Standard Review Plan for Review of License
Renewal Applications for Nuclear Power Plants,'' NUREG-1800, Revision 2
(ADAMS Accession No. ML103490036), was issued in December 2010, to
ensure the quality and uniformity of NRC staff reviews of license
renewal applications and to present a well-defined basis on which the
NRC staff evaluates the applicant's aging management programs and
activities. In April 2011, the NRC also issued ``Disposition of Public
Comments and Technical Bases for Changes in the License Renewal
Guidance Documents NUREG-1801 and NUREG-1800,'' NUREG-1950 (ADAMS
Accession No. ML11116A062), which describes the technical bases for the
changes in Revision 2 of the GALL report and Revision 2 of the standard
review plan (SRP) for review of license renewal applications.
Revision 2 of the GALL report, in Sections XI.M1, XI.S1, XI.S2,
XI.M3, XI.M5, XI.M6, XI.M11B and XI.S3, describes the evaluation and
technical bases for determining the sufficiency of ASME BPV Code
Subsections IWB, IWC, IWD, IWE, IWF, or IWL for managing aging during
the period of extended operation (i.e., up to 60 years of operation).
In addition, many other AMPs in the GALL report rely, in part but to a
lesser degree, on the requirements specified in the ASME BPV Code,
Section XI. Revision 2 of the GALL report also states that the 1995
Edition through the 2004 Edition of the ASME BPV Code, Section XI,
Subsections IWB, IWC, IWD, IWE, IWF, or IWL, as modified and limited by
Sec. 50.55a, were found to be acceptable editions and addenda for
complying with the requirements of Sec. 54.21(a)(3), unless
specifically noted in certain sections of the GALL report. The GALL
report further states that future Federal Register documents that amend
Sec. 50.55a will discuss the acceptability of editions
[[Page 56181]]
and addenda more recent than the 2004 Edition for their applicability
to license renewal. In a final rule issued on June 21, 2011 (76 FR
36232), subsequent to Revision 2 of the GALL report, the NRC also found
that the 2004 Edition with the 2005 Addenda through the 2007 Edition
with the 2008 Addenda of Section XI of the ASME BPV Code, Subsections
IWB, IWC, IWD, IWE, IWF, or IWL, as subject to the conditions in Sec.
50.55a, are acceptable for the AMPs in the GALL report and the
conclusions of the GALL report remain valid with the augmentations
specifically noted in the GALL report. In a final rule issued on July
18, 2017 (82 FR 32934), the NRC further finds that the 2009 Addenda
through the 2013 Edition of Section XI of the ASME BPV Code,
Subsections IWB, IWC, IWD, IWE, IWF, or IWL, as subject to the
conditions in Sec. 50.55a, will be acceptable for the AMPs in the GALL
report.
In July 2017, the NRC issued ``Generic Aging Lessons Learned for
Subsequent License Renewal (GALL-SLR) Report,'' NUREG-2191 (ADAMS
Accession Nos. ML17187A031 and ML17187A204), for applicants to use in
preparing applications for subsequent license renewal. The GALL-SLR
report provides AMPs that are sufficient for aging management for the
subsequent period of extended operation (i.e., up to 80 years of
operation), as required in Sec. 54.21(a)(3). The NRC also issued
``Standard Review Plan for Review of Subsequent License Renewal
Applications for Nuclear Power Plants,'' (SRP-SLR), NUREG-2192 in July
2017 (ADAMS Accession No. ML17188A158). In a similar manner as the GALL
report does, the GALL-SLR report, in Sections XI.M1, XI.S1, XI.S2,
XI.M3, XI.11B, and XI.S3, describes the evaluation and technical bases
for determining the sufficiency of ASME BPV Code Subsections IWB, IWC,
IWD, IWE, IWF, or IWL for managing aging during the subsequent period
of extended operation. Many other AMPs in the GALL-SLR report rely, in
part but to a lesser degree, on the requirements specified in the ASME
BPV Code, Section XI. The GALL-SLR report also indicates that the 1995
Edition through the 2013 Edition of the ASME BPV Code, Section XI,
Subsections IWB, IWC, IWD, IWE, IWF, or IWL, as subject to the
conditions in Sec. 50.55a, are acceptable for complying with the
requirements of Sec. 54.21(a)(3), unless specifically noted in certain
sections of the GALL-SLR report.
Evaluation With Respect to Aging Management
As part of this proposed rule, the NRC evaluated whether those AMPs
in the GALL report and GALL-SLR report which rely upon Subsections IWB,
IWC, IWD, IWE, IWF, or IWL of Section XI in the editions and addenda of
the ASME BPV Code incorporated by reference into Sec. 50.55a, in
general continue to be acceptable if the AMP relies upon these
Subsections in the 2015 Edition and the 2017 Edition. In general the
NRC finds that the 2015 Edition and the 2017 Edition of Section XI of
the ASME BPV Code, Subsections IWB, IWC, IWD, IWE, IWF, or IWL, as
subject to the conditions of this proposed rule, are acceptable for the
AMPs in the GALL report and GALL-SLR report and the conclusions of the
GALL report and GALL-SLR report remain valid with the exception of
augmentation, specifically noted in those reports. Accordingly, an
applicant for license renewal (including subsequent license renewal)
may use, in its plant-specific license renewal application, Subsections
IWB, IWC, IWD, IWE, IWF, or IWL of Section XI of the 2015 Edition and
the 2017 Edition of the ASME BPV Code, as subject to the conditions in
this proposed rule, without additional justification. Similarly, a
licensee approved for license renewal that relied on the AMPs may use
Subsections IWB, IWC, IWD, IWE, IWF, or IWL of Section XI of the 2015
Edition and the 2017 Edition of the ASME BPV Code. However, applicants
must assess and follow applicable NRC requirements with regard to
licensing basis changes and evaluate the possible impact on the
elements of existing AMPs.
Some of the AMPs in the GALL report and GALL-SLR report recommend
augmentation of certain Code requirements in order to ensure adequate
aging management for license renewal. The technical and regulatory
aspects of the AMPs for which augmentations are recommended also apply
if the 2015 Edition and the 2017 Edition of Section XI of the ASME BPV
Code are used to meet the requirements of Sec. 54.21(a)(3). The NRC
staff evaluated the changes in the 2015 Edition and the 2017 Edition of
Section XI of the ASME BPV Code to determine if the augmentations
described in the GALL report and GALL-SLR report remain necessary; the
NRC staff's evaluation has concluded that the augmentations described
in the GALL and GALL-SLR reports are necessary to ensure adequate aging
management.
For example, GALL-SLR report AMP XI.S3, ``ASME Section XI,
Subsection IWF'', recommends that volumetric examination consistent
with that of ASME BPV Code, Section XI, Table IWB-2500-1, Examination
Category B-G-1 should be performed to detect cracking for high strength
structural bolting (actual measured yield strength greater than or
equal to 150 kilopound per square inch (ksi)) in sizes greater than 1
inch nominal diameter. The GALL-SLR report also indicates that this
volumetric examination may be waived with adequate plant-specific
justification. This guidance for aging management in the GALL-SLR
report is the augmentation of the visual examination specified in
Subsection IWF of the 2015 Edition and the 2017 Edition of ASME BPV
Code, Section XI.
A license renewal applicant may either augment its AMPs as
described in the GALL report and GALL-SLR report (for operation up to
60 and 80 years respectively), or propose alternatives for the NRC to
review as part of the applicant's plant-specific justification for its
AMPs.
VI. Specific Request for Comment
The NRC is considering changes to Sec. 50.55a(g)(6)(ii)(D)
Augmented ISI requirements: Reactor vessel head inspections. As
previously discussed in the document, the NRC proposes to add a new
condition to address the use of the term ``sister plants'' for the
examinations of RPV upper heads. The use of sister plants under ASME
BPV Code Case N-729-6 would allow extension of the volumetric
inspection of replaced RPV heads with resistant materials from the
current 10-year inspection frequency to a period of up to 40 years. The
NRC is proposing a condition to prohibit the use of the concept of
sister plants. The NRC is evaluating both the definition of sister
plants and factors of improvement between the growth of PWSCC in alloys
600/82/182 and 690/52/152. It is unclear whether the current criteria
for sister plants (i.e., same owner) are appropriate. The NRC also
questions whether other criteria, such as environment, alloy heat, and
number of sisters in a particular group, should be included in the
definition. The NRC continues to review information on PWSCC growth
rates and factors of improvement for alloy 690/52/152 and 600/82/182 as
proposed in MRP-386. While the NRC has concluded that crack growth in
alloy 690/52/152 is sufficiently slower than in alloy 600/82/182 to
support an inspection interval of 20 years, work continues in assessing
whether the data and analyses support a 40-year interval.
[[Page 56182]]
The NRC is interested in receiving public input that addresses
whether there are reasonable changes to the definition of the term
``sister plants'' that would better identify heads with enough material
similarities such that examination of one head can be representative of
all others in the group.
VII. Plain Writing
The Plain Writing Act of 2010 (Pub. L. 111-274) requires Federal
agencies to write documents in a clear, concise, and well-organized
manner. The NRC has written this document to be consistent with the
Plain Writing Act as well as the Presidential Memorandum, ``Plain
Language in Government Writing,'' published June 10, 1998 (63 FR
31883). The NRC requests comment on this document with respect to the
clarity and effectiveness of the language used.
VIII. Voluntary Consensus Standards
The National Technology Transfer and Advancement Act of 1995,
Public Law 104-113 (NTTAA), and implementing guidance in U.S. Office of
Management and Budget (OMB) Circular A-119 (February 10, 1998),
requires that Federal agencies use technical standards that are
developed or adopted by voluntary consensus standards bodies unless
using such a standard is inconsistent with applicable law or is
otherwise impractical. The NTTAA requires Federal agencies to use
industry consensus standards to the extent practical; it does not
require Federal agencies to endorse a standard in its entirety. Neither
the NTTAA nor Circular A-119 prohibit an agency from adopting a
voluntary consensus standard while taking exception to specific
portions of the standard, if those provisions are deemed to be
``inconsistent with applicable law or otherwise impractical.''
Furthermore, taking specific exceptions furthers the Congressional
intent of Federal reliance on voluntary consensus standards because it
allows the adoption of substantial portions of consensus standards
without the need to reject the standards in their entirety because of
limited provisions that are not acceptable to the agency.
In this proposed rule, the NRC is continuing its existing practice
of establishing requirements for the design, construction, operation,
ISI (examination) and IST of nuclear power plants by approving the use
of the latest editions and addenda of the ASME BPV and OM Codes (ASME
Codes) in Sec. 50.55a. The ASME Codes are voluntary consensus
standards, developed by participants with broad and varied interests,
in which all interested parties (including the NRC and licensees of
nuclear power plants) participate. Therefore, the NRC's incorporation
by reference of the ASME Codes is consistent with the overall
objectives of the NTTAA and OMB Circular A-119.
As discussed in Section III of this document, this proposed rule
would condition the use of certain provisions of the 2015 and 2017
Editions to the ASME BPV Code, Section III, Division 1 and the ASME BPV
Code, Section XI, Division 1, as well as the 2015 and 2017 Editions to
the ASME OM Code. In addition, the NRC is proposing to not adopt
(``excludes'') certain provisions of the ASME Codes as discussed in
this document, and in the regulatory and backfit analysis for this
proposed rule. The NRC believes that this proposed rule complies with
the NTTAA and OMB Circular A-119 despite these conditions and
``exclusions.''
If the NRC did not conditionally accept ASME editions, addenda, and
code cases, the NRC would disapprove them entirely. The effect would be
that licensees and applicants would submit a larger number of requests
for the use of alternatives under Sec. 50.55a(z), requests for relief
under Sec. 50.55a(f) and (g), or requests for exemptions under Sec.
50.12 and/or Sec. 52.7. These requests would likely include broad-
scope requests for approval to issue the full scope of the ASME Code
editions and addenda which would otherwise be approved as proposed in
this proposed rule (i.e., the request would not be simply for approval
of a specific ASME Code provision with conditions). These requests
would be an unnecessary additional burden for both the licensee and the
NRC, inasmuch as the NRC has already determined that the ASME Codes and
Code Cases that are the subject of this proposed rule are acceptable
for use (in some cases with conditions). For these reasons, the NRC
concludes that this proposed rule's treatment of ASME Code editions and
addenda, and code cases and any conditions placed on them does not
conflict with any policy on agency use of consensus standards specified
in OMB Circular A-119.
The NRC did not identify any other voluntary consensus standards
developed by U.S. voluntary consensus standards bodies for use within
the U.S. that the NRC could incorporate by reference instead of the
ASME Codes. The NRC also did not identify any voluntary consensus
standards developed by multinational voluntary consensus standards
bodies for use on a multinational basis that the NRC could incorporate
by reference instead of the ASME Codes. The NRC identified codes
addressing the same subject as the ASME Codes for use in individual
countries. At least one country, Korea, directly translated the ASME
Code for use in that country. In other countries (e.g., Japan), ASME
Codes were the basis for development of the country's codes, but the
ASME Codes were substantially modified to accommodate that country's
regulatory system and reactor designs. Finally, there are countries
(e.g., the Russian Federation) where that country's code was developed
without regard to the ASME Code. However, some of these codes may not
meet the definition of a voluntary consensus standard because they were
developed by the state rather than a voluntary consensus standards
body. Evaluation by the NRC of the countries' codes to determine
whether each code provides a comparable or enhanced level of safety
when compared against the level of safety provided under the ASME Codes
would require a significant expenditure of agency resources. This
expenditure does not seem justified, given that substituting another
country's code for the U.S. voluntary consensus standard does not
appear to substantially further the apparent underlying objectives of
the NTTAA.
In summary, this proposed rule satisfies the requirements of the
NTTAA and OMB Circular A-119.
IX. Incorporation by Reference--Reasonable Availability to Interested
Parties
The NRC proposes to incorporate by reference four recent editions
to the ASME Codes for nuclear power plants and two revised ASME Code
Cases. As described in the ``Background'' and ``Discussion'' sections
of this document, these materials contain standards for the design,
fabrication, and inspection of nuclear power plant components. The NRC
also proposes to incorporate by reference an EPRI Topical Report. As
described in the ``Background'' and ``Discussion'' sections of this
document, this report contains proposed requirements related to the two
revised ASME Code Cases.
The NRC is required by law to obtain approval for incorporation by
reference from the Office of the Federal Register (OFR). The OFR's
requirements for incorporation by reference are set forth in 1 CFR part
51. On November 7, 2014, the OFR adopted changes to its regulations
governing incorporation by reference (79 FR 66267). The OFR regulations
require an agency to include in a proposed rule a discussion of the
ways that the materials the agency proposes to incorporate by reference
are
[[Page 56183]]
reasonably available to interested parties or how it worked to make
those materials reasonably available to interested parties. The
discussion in this section complies with the requirement for proposed
rules as set forth in Sec. 51.5(a)(1).
The NRC considers ``interested parties'' to include all potential
NRC stakeholders, not only the individuals and entities regulated or
otherwise subject to the NRC's regulatory oversight. These NRC
stakeholders are not a homogenous group but vary with respect to the
considerations for determining reasonable availability. Therefore, the
NRC distinguishes between different classes of interested parties for
the purposes of determining whether the material is ``reasonably
available.'' The NRC considers the following to be classes of
interested parties in NRC rulemakings with regard to the material to be
incorporated by reference:
Individuals and small entities regulated or otherwise
subject to the NRC's regulatory oversight (this class also includes
applicants and potential applicants for licenses and other NRC
regulatory approvals) and who are subject to the material to be
incorporated by reference by rulemaking. In this context, ``small
entities'' has the same meaning as a ``small entity'' under Sec.
2.810.
Large entities otherwise subject to the NRC's regulatory
oversight (this class also includes applicants and potential applicants
for licenses and other NRC regulatory approvals) and who are subject to
the material to be incorporated by reference by rulemaking. In this
context, ``large entities'' are those which do not qualify as a ``small
entity'' under Sec. 2.810.
Non-governmental organizations with institutional
interests in the matters regulated by the NRC.
Other Federal agencies, states, local governmental bodies
(within the meaning of Sec. 2.315(c)).
Federally-recognized and State-recognized \4\ Indian
tribes.
---------------------------------------------------------------------------
\4\ State-recognized Indian tribes are not within the scope of
Sec. 2.315(c). However, for purposes of the NRC's compliance with 1
CFR 51.5, ``interested parties'' includes a broad set of
stakeholders, including State-recognized Indian tribes.
---------------------------------------------------------------------------
Members of the general public (i.e., individual,
unaffiliated members of the public who are not regulated or otherwise
subject to the NRC's regulatory oversight) who may wish to gain access
to the materials which the NRC proposes to incorporate by reference by
rulemaking in order to participate in the rulemaking process.
The NRC makes the materials to be incorporated by reference
available for inspection to all interested parties, by appointment, at
the NRC Technical Library, which is located at Two White Flint North,
11545 Rockville Pike, Rockville, Maryland 20852; telephone: 301-415-
7000; email: [email protected].
Interested parties may obtain a copy of the EPRI Topical Report
free of charge from EPRI from their website at www.epri.com.
Interested parties may purchase a copy of the ASME materials from
ASME at Three Park Avenue, New York, NY 10016, or at the ASME website
https://www.asme.org/shop/standards. The materials are also accessible
through third-party subscription services such as IHS (15 Inverness Way
East, Englewood, CO 80112; https://global.ihs.com) and Thomson Reuters
Techstreet (3916 Ranchero Dr., Ann Arbor, MI 48108; http://www.techstreet.com). The purchase prices for individual documents range
from $225 to $720 and the cost to purchase all documents is
approximately $9,000.
For the class of interested parties constituting members of the
general public who wish to gain access to the materials to be
incorporated by reference in order to participate in the rulemaking,
the NRC recognizes that the $9,000 cost may be so high that the
materials could be regarded as not reasonably available for purposes of
commenting on this rulemaking, despite the NRC's actions to make the
materials available at the NRC's PDR. Accordingly, the NRC sent a
letter to the ASME requesting that they consider enhancing public
access to these materials during the public comment period (ADAMS
Accession No. ML17310A186). In a May 30, 2018, email to the NRC, the
ASME agreed to make the materials available online in a read-only
electronic access format during the public comment period (ADAMS
Accession No. ML18157A113). Therefore, the four editions to the ASME
Codes for nuclear power plants, and the two ASME Code Cases which the
NRC proposes to incorporate by reference in this rulemaking are
available in read-only format at the ASME website http://go.asme.org/NRC.
The NRC concludes that the materials the NRC proposes to
incorporate by reference in this proposed rule are reasonably available
to all interested parties because the materials are available to all
interested parties in multiple ways and in a manner consistent with
their interest in the materials.
X. Environmental Assessment and Final Finding of No Significant
Environmental Impact
This proposed rule action is in accordance with the NRC's policy to
incorporate by reference in Sec. 50.55a new editions and addenda of
the ASME BPV and OM Codes to provide updated rules for constructing and
inspecting components and testing pumps, valves, and dynamic restraints
(snubbers) in light-water nuclear power plants. The ASME Codes are
national voluntary consensus standards and are required by the NTTAA to
be used by government agencies unless the use of such a standard is
inconsistent with applicable law or otherwise impractical. The National
Environmental Policy Act (NEPA) requires Federal agencies to study the
impacts of their ``major Federal actions significantly affecting the
quality of the human environment,'' and prepare detailed statements on
the environmental impacts of the proposed action and alternatives to
the proposed action (42 U.S.C. 4332(C); NEPA Sec. 102(C)).
The NRC has determined under NEPA, as amended, and the NRC's
regulations in subpart A of 10 CFR part 51, that this proposed rule is
not a major Federal action significantly affecting the quality of the
human environment and, therefore, an environmental impact statement is
not required. The rulemaking does not significantly increase the
probability or consequences of accidents, no changes are being made in
the types of effluents that may be released off-site, and there is no
significant increase in public radiation exposure. The NRC concludes
that the increase in occupational exposure would not be significant.
This proposed rule does not involve non-radiological plant effluents
and has no other environmental impact. Therefore, no significant non-
radiological impacts are associated with this action. The determination
of this environmental assessment is that there will be no significant
off-site impact to the public from this action. Therefore, a finding of
no significant impacts (FONSI) is appropriate.
XI. Paperwork Reduction Act Statement
This proposed rule contains new or amended collections of
information subject to the Paperwork Reduction Act of 1995 (44 U.S.C.
3501 et seq.). This proposed rule has been submitted to the Office of
Management and Budget for review and approval of the information
collections.
[[Page 56184]]
Type of submission, new or revision: Revision.
The title of the information collection: Domestic Licensing of
Production and Utilization Facilities: Incorporation by Reference of
American Society of Mechanical Engineers Codes and Code Cases.
The form number if applicable: Not applicable.
How often the collection is required or requested: On occasion.
Who will be required or asked to respond: Power reactor licensees
and applicants for power reactors under construction.
An estimate of the number of annual responses: -53.
The estimated number of annual respondents: 103.
An estimate of the total number of hours needed annually to comply
with the information collection requirement or request: -12,640.
Abstract: This proposed rule is the latest in a series of
rulemakings to amend the NRC's regulations to incorporate by reference
revised and updated ASME Codes for nuclear power plants. The number of
operating nuclear power plants has decreased and the NRC has increased
its estimate of the burden associated with developing alternative
requests. Overall, the reporting burden for Sec. 50.55a has increased.
The U.S. Nuclear Regulatory Commission is seeking public comment on
the potential impact of the information collections contained in this
proposed rule and on the following issues:
1. Is the proposed information collection necessary for the proper
performance of the functions of the NRC, including whether the
information will have practical utility?
2. Is the estimate of the burden of the proposed information
collection accurate?
3. Is there a way to enhance the quality, utility, and clarity of
the information to be collected?
4. How can the burden of the proposed information collection on
respondents be minimized, including the use of automated collection
techniques or other forms of information technology?
A copy of the OMB clearance package and proposed rule is available
in ADAMS (Accession Nos. ML18150A267 and ML18150A265) or may be viewed
free of charge at the NRC's PDR, One White Flint North, 11555 Rockville
Pike, Room O-1 F21, Rockville, MD 20852. You may obtain information and
comment submissions related to the OMB clearance package by searching
on http://www.regulations.gov under Docket ID NRC-2016-0082.
You may submit comments on any aspect of these proposed information
collection(s), including suggestions for reducing the burden and on the
previously stated issues, by the following methods:
Federal Rulemaking website: Go to http://www.regulations.gov and search for Docket ID NRC-2016-0082.
Mail comments to: Information Services Branch, Office of
the Chief Information Officer, U.S. Nuclear Regulatory Commission,
Washington, DC 20555-0001 or to the OMB reviewer at: OMB Office of
Information and Regulatory Affairs (3150-0011), Attn: Desk Officer for
the Nuclear Regulatory Commission, 725 17th Street NW, Washington, DC
20503; email: [email protected].
Submit comments by December 10, 2018. Comments received after this
date will be considered if it is practical to do so, but the NRC staff
is able to ensure consideration only for comments received on or before
this date.
Public Protection Notification
The NRC may not conduct or sponsor, and a person is not required to
respond to, a collection of information unless the document requesting
or requiring the collection displays a currently valid OMB control
number.
XII. Regulatory Analysis
The NRC has prepared a draft regulatory analysis on this proposed
rule. The analysis examines the costs and benefits of the alternatives
considered by the Commission. The NRC requests public comments on the
draft regulatory analysis, (ADAMS Accession No. ML18150A267). Comments
on the draft analysis may be submitted to the NRC by any method
provided in the ADDRESSES section of this document.
XIII. Backfitting and Issue Finality
Introduction
The NRC's Backfit Rule in Sec. 50.109 states that the NRC shall
require the backfitting of a facility only when it finds the action to
be justified under specific standards stated in the rule. Section
50.109(a)(1) defines backfitting as the modification of or addition to
systems, structures, components, or design of a facility; the design
approval or manufacturing license for a facility; or the procedures or
organization required to design, construct, or operate a facility. Any
of these modifications or additions may result from a new or amended
provision in the NRC's rules or the imposition of a regulatory position
interpreting the NRC's rules that is either new or different from a
previously applicable NRC position after issuance of the construction
permit or the operating license or the design approval.
Section 50.55a requires nuclear power plant licensees to:
Construct ASME BPV Code Class 1, 2, and 3 components in
accordance with the rules provided in Section III, Division 1, of the
ASME BPV Code (``Section III'').
Inspect Class 1, 2, 3, Class MC, and Class CC components
in accordance with the rules provided in Section XI, Division 1, of the
ASME BPV Code (``Section XI'').
Test Class 1, 2, and 3 pumps, valves, and dynamic
restraints (snubbers) in accordance with the rules provided in the ASME
OM Code.
This rulemaking proposes to incorporate by reference the 2015 and
2017 Editions to the ASME BPV Code, Section III, Division 1 and ASME
BPV Code, Section XI, Division 1, as well as the 2015 and 2017 Editions
to the ASME OM Code.
The ASME BPV and OM Codes are national consensus standards
developed by participants with broad and varied interests, in which all
interested parties (including the NRC and utilities) participate. A
consensus process involving a wide range of stakeholders is consistent
with the NTTAA, inasmuch as the NRC has determined that there are sound
regulatory reasons for establishing regulatory requirements for design,
maintenance, ISI, and IST by rulemaking. The process also facilitates
early stakeholder consideration of backfitting issues. Thus, the NRC
believes that the NRC need not address backfitting with respect to the
NRC's general practice of incorporating by reference updated ASME
Codes.
Overall Backfitting Considerations: Section III of the ASME BPV Code
Incorporation by reference of more recent editions and addenda of
Section III of the ASME BPV Code does not affect a plant that has
received a construction permit or an operating license or a design that
has been approved. This is because the edition and addenda to be used
in constructing a plant are, under Sec. 50.55a, determined based on
the date of the construction permit, and are not changed thereafter,
except voluntarily by the licensee. The incorporation by reference of
more recent editions and addenda of Section III ordinarily applies only
to applicants after the effective date of the final rule incorporating
these new editions and
[[Page 56185]]
addenda. Thus, incorporation by reference of a more recent edition and
addenda of Section III does not constitute ``backfitting'' as defined
in Sec. 50.109(a)(1).
Overall Backfitting Considerations: Section XI of the ASME BPV Code and
the ASME OM Code
Incorporation by reference of more recent editions and addenda of
Section XI of the ASME BPV Code and the ASME OM Code affects the ISI
and IST programs of operating reactors. However, the Backfit Rule
generally does not apply to incorporation by reference of later
editions and addenda of the ASME BPV Code (Section XI) and OM Code. As
previously mentioned, the NRC's longstanding regulatory practice has
been to incorporate later versions of the ASME Codes into Sec. 50.55a.
Under Sec. 50.55a, licensees shall revise their ISI and IST programs
every 120 months to the latest edition and addenda of Section XI of the
ASME BPV Code and the ASME OM Code incorporated by reference into Sec.
50.55a 12 months before the start of a new 120-month ISI and IST
interval. Thus, when the NRC approves and requires the use of a later
version of the Code for ISI and IST, it is implementing this
longstanding regulatory practice and requirement.
Other circumstances where the NRC does not apply the Backfit Rule
to the approval and requirement to use later Code editions and addenda
are as follows:
1. When the NRC takes exception to a later ASME BPV Code or OM Code
provision but merely retains the current existing requirement,
prohibits the use of the later Code provision, limits the use of the
later Code provision, or supplements the provisions in a later Code.
The Backfit Rule does not apply because the NRC is not imposing new
requirements. However, the NRC explains any such exceptions to the Code
in the Statement of Considerations and regulatory analysis for the
rule.
2. When an NRC exception relaxes an existing ASME BPV Code or OM
Code provision but does not prohibit a licensee from using the existing
Code provision. The Backfit Rule does not apply because the NRC is not
imposing new requirements.
3. Modifications and limitations imposed during previous routine
updates of Sec. 50.55a have established a precedent for determining
which modifications or limitations are backfits, or require a backfit
analysis (e.g., final rule dated September 10, 2008 [73 FR 52731], and
a correction dated October 2, 2008 [73 FR 57235]). The application of
the backfit requirements to modifications and limitations in the
current rule are consistent with the application of backfit
requirements to modifications and limitations in previous rules.
The incorporation by reference and adoption of a requirement
mandating the use of a later ASME BPV Code or OM Code may constitute
backfitting in some circumstances. In these cases, the NRC would
perform a backfit analysis or documented evaluation in accordance with
Sec. 50.109. These include the following:
1. When the NRC endorses a later provision of the ASME BPV Code or
OM Code that takes a substantially different direction from the
existing requirements, the action is treated as a backfit (e.g., 61 FR
41303; August 8, 1996).
2. When the NRC requires implementation of a later ASME BPV Code or
OM Code provision on an expedited basis, the action is treated as a
backfit. This applies when implementation is required sooner than it
would be required if the NRC simply endorsed the Code without any
expedited language (e.g., 64 FR 51370; September 22, 1999).
3. When the NRC takes an exception to an ASME BPV Code or OM Code
provision and imposes a requirement that is substantially different
from the existing requirement as well as substantially different from
the later Code (e.g., 67 FR 60529; September 26, 2002).
Detailed Backfitting Discussion: Proposed Changes Beyond Those
Necessary To Incorporate by Reference the New ASME BPV and OM Code
Provisions
This section discusses the backfitting considerations for all the
proposed changes to Sec. 50.55a that go beyond the minimum changes
necessary and required to adopt the new ASME Code Addenda into Sec.
50.55a.
ASME BPV Code, Section III
1. Add Sec. 50.55a(b)(1)(x) to require compliance with two new
conditions related to visual examination of bolts studs and nuts.
Visual examination is one of the processes for acceptance of the final
product to ensure its structural integrity and its ability to perform
its intended function. The 2015 Edition of the ASME Code contains
requirements for visual inspection of these components, however, the
2017 Edition does not require these visual examinations to be performed
in accordance with NX-5100 and NX-5500. Therefore, the NRC proposes to
add two conditions to ensure adequate procedures remain and qualified
personnel remain capable of determining the structural integrity of
these components. Since the proposed conditions restore requirements
that were removed from the latest edition of the ASME Code, the
proposed conditions does not constitute a new or changed NRC position.
Therefore, the revision of this condition is not a backfit
2. Add Sec. 50.55a(b)(1)(xi) to require conditions on the use of
ASME BPV Code, Section III, Appendix XXVI for installation of high
density polyethylene (HDPE) pressure piping. This Appendix is new in
the 2015 Edition of Section III, since it is the first time the ASME
BPV Code has provided rules for the use of polyethylene piping. The use
of HDPE is newly allowed by the Code, which provides alternatives to
the use of current materials. Therefore, this proposed change is not a
backfit.
3. Add Sec. 50.55a(b)(1)(xii) to prohibit applicants and licensees
from using a certifying engineer in lieu of a registered professional
engineer for code related activities that are applicable to U.S.
nuclear facilities regulated by the NRC. In the 2017 Edition of ASME
BPV Code, Section III, Subsection NCA, the several Subsections were
updated to replace the term ``registered professional engineer,'' with
term ``certifying engineer'' to be consistent with ASME BPV Code
Section III Mandatory Appendix XXIII.
The NRC reviewed these changes and has determined that the use of a
certifying engineer in lieu of a registered professional engineer is
only applicable for non-U.S. nuclear facilities. Since the use of a
certifying engineer is newly allowed by the Code, the addition of the
condition that prohibits the use of a certifying engineer in lieu of a
registered professional engineer for code related activities is not a
backfit.
ASME BPV Code, Section XI
1. Revise Sec. 50.55a(b)(2)(ix) to require compliance with new
condition Sec. 50.55a(b)(2)(ix)(K). The NRC has developed proposed
condition Sec. 50.55a(b)(2)(ix)(K) to ensure containment leak-chase
channel systems are properly inspected. This condition serves to
clarify the NRC's existing expectations, as described in inspection
reports and IN 2014-07, and will be applicable to all editions of the
ASME Code, prior to the 2017 Edition. The NRC considers this condition
a clarification of the existing expectations and, therefore, does not
consider this condition a backfit.
As noted previously, after issuance of the IN, the NRC received
feedback during an August 22, 2014, public meeting between NRC and ASME
[[Page 56186]]
management (ADAMS Accession No. ML14245A003), noting that the IN
guidance appeared to be in conflict with ASME Section XI Interpretation
XI-1-13-10. In response to the comment during the public meeting, the
NRC issued a letter to ASME (ADAMS Accession No. ML14261A051) which
stated the NRC believes the IN is consistent with the requirements in
the ASME Code and restated the existing NRC staff position. ASME
responded to the NRC's letter (ADAMS Accession No. ML15106A627) and
noted that a condition in the regulations may be appropriate to clarify
the NRC staff's position.
2. Revise Sec. 50.55a(b)(2)(xx)(B) to clarify the condition with
respect to the NRC's expectations for system leakage tests performed in
lieu of a hydrostatic pressure test following repair/replacement
activities performed by welding or brazing on a pressure retaining
boundary using the 2003 Addenda through the latest edition and addenda
of ASME BPV Code, Section XI incorporated by reference in paragraph
Sec. 50.55a(a)(1)(ii). This provision requires the licensee perform
the applicable nondestructive testing that would be required by the
1992 Edition or later of ASME BPV Code, Section III. The nondestructive
examination method (e.g. surface, volumetric, etc.) and acceptance
criteria of the 1992 Edition or later of Section III shall be met and a
system leakage test be performed in accordance with IWA-5211(a). The
actual nondestructive examination and pressure testing may be performed
using procedures and personnel meeting the requirements of the
licensee's/applicant's current ISI code of record required by Sec.
50.55a(g)(4). The proposed condition does not constitute a new or
changed NRC position. Therefore, the revision of this condition is not
a backfit.
3. Add Sec. 50.55a(b)(2)(xx)(C) to place two conditions on the use
of the alternative BWR Class 1 system leakage test described in IWA-
5213(b)(2), IWB-5210(c) and IWB-5221(d) of the 2017 Edition of ASME
Section XI. This is a new pressure test allowed by the Code at a
reduced pressure as an alternative to the pressure test currently
required. This allows a reduction in the requirements which is
consistent with several NRC-approved alternatives/relief requests.
Therefore, this proposed change is not a backfit.
4. Add Sec. 50.55a(b)(2)(xxi)(B) to require the plant-specific
evaluation demonstrating the criteria of IWB-2500(f) are met be
maintained in accordance with the Owners requirements, to prohibit use
of the provisions of IWB-2500(f) and Table IWB-2500-1 Note 6 for of
Examination Category B-D Item Numbers B3.90 and B3.100 for plants with
renewed licenses and to restrict the provisions of IWB-2500(g) and
Table IWB-2500-1 Notes 6 and 7 for examination of Examination Category
B-D Item Numbers B3.90 and B3.100 use to eliminate the preservice or
inservice volumetric examination of plants with a Combined Operating
License pursuant to 10 CFR part 52, or a plant that receives its
operating license after October 22, 2015. This proposed revision
applies the current requirements for use of these provisions as
currently described in ASME Code Case N-702, which are currently
allowed through Regulatory Guide 1.147, Revision 19. Therefore, the NRC
does not consider the clarification to be a change in requirements.
Therefore, this proposed change is not a backfit.
5. Revise the condition found in Sec. 50.55a(b)(2)(xxv) to allow
the use of IWA-4340 of Section XI, 2011 Addenda through 2017 Edition
with conditions.
Add Sec. 50.55a(b)(2)(xxv)(A) which will continue the prohibition
of IWA-4340 for Section XI editions and addenda prior to the 2011
Addenda. This prohibition applies the current requirements for use of
these provision, therefore, the NRC does not consider the addition of
Sec. 50.55a(b)(2)(xxv)(A) to be a change in requirements. Therefore,
this proposed change is not a backfit.
Add Sec. 50.55a(b)(2)(xxv)(B) which will allow the use of IWA-4340
of Section XI, 2011 Addenda through 2017 Edition with three conditions.
The first proposed condition would prohibit the use of
IWA-4340 on crack-like defects or those associated with flow
accelerated corrosion.
The design requirements and potentially the periodicity of followup
inspections might not be adequate for crack-like defects that could
propagate much faster than defects due to loss of material. Prior to
the change to allow the use of IWA-4340, the provisions of this
subsubarticle were not permitted for any type of defects. By
establishment of the new conditions, the NRC proposes to allow the use
of IWA-4340 for defects such as wall loss due to general corrosion.
Establishing a condition to not allow the use of IWA-4340 for crack-
like defects does not constitute a new or changed NRC position.
Therefore, the revision of this condition associated with crack-like
defects is not a backfit.
As established in NUREG-1801, ``Generic Aging Lessons Learned
(GALL) Report'', Revision 2, effective management of flow accelerated
corrosion entails: (a) An analysis to determine critical locations, (b)
limited baseline inspections to determine the extent of thinning at
these locations, (c) use of a predictive Code (e.g., CHECKWORKS); and
(d) follow-up inspections to confirm the predictions, or repairing or
replacing components as necessary. These provision are not included in
IWA-4340. In addition, subparagraph IWA-4421(c)(2) provides provisions
for restoring minimum required wall thickness by welding or brazing,
which can be used to mitigate a defect associated with flow accelerated
corrosion. The proposed condition related to flow accelerated corrosion
does not constitute a new or changed NRC position. Therefore, the
revision of this condition is not a backfit.
The second proposed condition would require the design of
a modification that mitigates a defect to incorporate a loss of
material rate either 2 times the actual measured corrosion rate in that
pipe location, or 4 times the estimated maximum corrosion rate for the
piping system. This condition is consistent with Code Case N-789,
``Alternative Requirements for Pad Reinforcement of Class 2 and 3
Moderate-Energy Carbon Steel Piping, Section XI, Division 1,'' Section
3, ``Design.'' The NRC has endorsed Code Case 789 in Regulatory Guide
1.147, ``Inservice Inspection Code Case Acceptability, ASME Section XI,
Division 1.'' The proposed condition does not constitute a new or
changed NRC position. Therefore, the revision of this condition is not
a backfit.
The third proposed condition would require the Owner to
perform a wall thickness examination in the vicinity of the
modification and relevant pipe base metal during each refueling outage
cycle to detect propagation of the flaw unless the projected flaw
propagation has been validated in two refueling outage cycles
subsequent to the installation of the modification. This condition is
consistent with Code Case N-789, Section 8, ``Inservice Monitoring,''
which requires followup wall thickness measurements to verify that the
minimum design thicknesses are maintained. The followup examination
requirements in IWA-4340 are inconsistent with the NRC endorsement of
Code Case 789 in Regulatory Guide 1.147 in that the inspections can be
limited to demonstrating that the flaw has not propagated into material
credited for structural integrity without validating the project flaw
growth. The proposed condition does not constitute a new or changed NRC
position. Therefore, the
[[Page 56187]]
revision of this condition is not a backfit.
6. Revise Sec. 50.55a(b)(2)(xxvi) to require that a system leakage
test be conducted after implementing a repair replacement activity on a
mechanical joint greater than NPS-1. The revision will also clarify
what Code edition/addenda may be used when conducting the pressure
test. This proposed revision clarifies the current requirements, which
the NRC considers to be consistent with the meaning and intent of the
current requirements. Therefore, the NRC does not consider the
clarification to be a change in requirements. Therefore, this proposed
change is not a backfit.
7. Revise Sec. 50.55a(b)(2)(xxxii) to clarify the requirement to
submit Summary Reports pre-2015 Edition and Owner Activity Reports in
the 2015 Edition of the ASME BPV Code. This proposed revision clarifies
the current requirements, which the NRC considers to be consistent with
the meaning and intent of the current requirements. Therefore, the NRC
does not consider the clarification to be a change in requirements.
Therefore, this proposed change is not a backfit.
8. Add Sec. 50.55a(b)(2)(xxxv)(B) which would condition the use of
2015 Edition of ASME BPV Code, Section XI, Appendix A, paragraph A-
4200(c), to define RTKIa in equation (a) as RTKIa
= T0 + 90.267 exp(-0.003406T0) in lieu of the equation shown in the
Code. When the equation was converted from SI units to U.S. Customary
units a mistake was made which makes the equation erroneous. The
equation shown above for RTKIa is the correct formula. This
is part of the newly revised Code, and the proposed addition of this
condition is not a new requirement and therefore not a backfit.
9. Revise Sec. 50.55a(b)(2)(xxxvi) to extend the applicability to
use of the 2015 and 2017 Editions of Section XI of the ASME BPV Code.
The condition was added in the 2009-2013 rulemaking and ASME did not
make changes in the 2015 or 2017 Editions of the ASME BPV Code;
therefore, the condition still applies but is not new to this proposed
rule. The NRC considers this revision to the condition to be consistent
with the meaning and intent of the current requirements. Therefore, the
NRC does not consider the clarification to be a change in requirements.
Therefore, this proposed change is not a backfit.
10. Add Sec. 50.55a(b)(2)(xxxviii) to condition ASME BPV Code,
Section XI, Appendix III, Supplement 2. Supplement 2 is closely-based
on ASME Code Case N-824, which was incorporated by reference with
conditions in Sec. 50.55a(a)(3)(ii). The conditions on ASME BPV Code,
Section XI, Appendix III, Supplement 2 are consistent with the
conditions on ASME Code Case N-824. Therefore, the NRC does not
consider this a new requirement. Therefore, this proposed change is not
a backfit.
11. Add Sec. 50.55a(b)(2)(xxxix) to condition the use of Section
XI, IWA-4421(c)(1) and IWA-4421(c)(2). The NRC considers these
conditions necessary as part of the allowance to use IWA-4340. The
proposed condition on the use of IWA-4421(c)(1) and IWA-4421(c)(2) does
not constitute a new or changed NRC position. Therefore, the addition
of this proposed condition is not a backfit.
12. Add Sec. 50.55a(b)(2)(xl) to prohibit the use of ASME BPV
Code, Section XI, Subparagraphs IWB-3510.4(b)(4) and IWB-3510.4(b)(5).
The proposed condition does not change the current material
requirements because the currently required testing to meet the
material requirements for those materials addressed by the new
condition would continue to be performed per the existing requirements.
Therefore this condition on the use of IWB-3510.4(b) does not
constitute a new or changed NRC position. Therefore, the addition of
this proposed condition is not a backfit.
13. Add Sec. 50.55a(b)(2)(xli) to prohibit the use of ASME BPV
Code, Section XI, Subparagraphs IWB-3112(a)(3) and IWC-3112(a)(3) in
the 2013 Edition of Section XI through the latest edition and addenda
incorporated by reference in paragraph (a)(1)(ii). The proposed
condition is consistent with the NRC`s current prohibition of these
items discussed in Regulatory Guide 1.193 in the discussion of ASME
Code Case N-813. Therefore, this condition does not constitute a new or
changed NRC position. Therefore, the addition of this proposed
condition is not a backfit.
14. Add Sec. 50.55a(b)(2)(xlii) to provide conditions for
Examination Category B-F, Item B5.11 and Item B5.71 in the 2011a
Addenda through the latest edition and addenda incorporated by
reference in previous paragraphs (a)(1)(ii) of this section. The
proposed conditions are consistent with the conditions on ASME Code
Case N-799 in Regulatory Guide 1.147. Therefore, these conditions do
not constitute a new or changed NRC position. Therefore, the addition
of these proposed conditions is not a backfit.
15. Revise Sec. 50.55a(g)(6)(ii)(D) to implement Code Case N-729-
6. On March 3, 2016, the ASME approved the sixth revision of ASME BPV
Code Case N-729, (N-729-6). The NRC proposes to update the requirements
of Sec. 50.55a(g)(6)(ii)(D) to require licensees to implement ASME BPV
Code Case N-729-6, with conditions. The ASME BPV Code Case N-729-6
contains similar requirements as N-729-4; however, N-729-6 also
contains new requirements to address peening mitigation and inspection
relief for replaced reactor pressure vessel heads with nozzles and
welds made of more crack resistant materials. The new NRC conditions on
the use of ASME BPV Code Case N-729-6 address operational experience,
clarification of implementation, and the use of alternatives to the
code case.
The current regulatory requirements for the examination of
pressurized water reactor upper RPV heads that use nickel-alloy
materials are provided in Sec. 50.55a(g)(6)(ii)(D). This section was
first created by rulemaking, dated September 10, 2008, (73 FR 52730) to
require licensees to implement ASME BPV Code Case N-729-1, with
conditions, instead of the examinations previously required by the ASME
BPV Code, Section XI. The action did constitute a backfit; however, the
NRC concluded that imposition of ASME BPV Code Case N-729-1, as
conditioned, constituted an adequate protection backfit.
The General Design Criteria (GDC) for nuclear power plants
(appendix A to 10 CFR part 50) or, as appropriate, similar requirements
in the licensing basis for a reactor facility, provide bases and
requirements for NRC assessment of the potential for, and consequences
of, degradation of the reactor coolant pressure boundary (RCPB). The
applicable GDC include GDC 14 (Reactor Coolant Pressure Boundary), GDC
31 (Fracture Prevention of Reactor Coolant Pressure Boundary), and GDC
32 (Inspection of Reactor Coolant Pressure Boundary). General Design
Criterion 14 specifies that the RCPB be designed, fabricated, erected,
and tested so as to have an extremely low probability of abnormal
leakage, of rapidly propagating failure, and of gross rupture. General
Design Criterion 31 specifies that the probability of rapidly
propagating fracture of the RCPB be minimized. General Design Criterion
32 specifies that components that are part of the RCPB have the
capability of being periodically inspected to assess their structural
and leak tight integrity.
The NRC concludes that incorporation by reference of Code Case N-
729-6, as conditioned, into Sec. 50.55a as a mandatory requirement
will continue to ensure reasonable assurance of adequate protection of
public health and safety. Updating the regulations to require using
ASME BPV Code Case N-
[[Page 56188]]
729-6, with conditions, ensures that potential flaws will be detected
before they challenge the structural or leak tight integrity of the
reactor pressure vessel upper head within current nondestructive
examination limitations. The code case provisions and the NRC's
proposed conditions on examination requirements for reactor pressure
vessel upper heads are essentially the same as those established under
ASME BPV Code Case N-729-4, as conditioned. Exceptions include: (1) An
introduction of examination relief for upper heads with Alloy 690
penetration nozzles to be examined volumetrically every 20 years in
accordance with Table 1 of ASME BPV Code Case N-729-6, (2) introduction
of peening as a mitigation technique along with requirements for
peening and inspection relief following peening and (3) substitution of
a volumetric leak path examination for a required surface examination
if a bare metal visual examination identifies a possible indication of
leakage.
The NRC continues to find that examinations of reactor pressure
vessel upper heads, their penetration nozzles, and associated partial
penetration welds are necessary for adequate protection of public
health and safety and that the requirements of ASME BPV Code Case N-
729-6, as conditioned, represent an acceptable approach, developed, in
part, by a voluntary consensus standards organization for performing
future inspections. The proposed NRC conditions on Code Case N-729-6
address newly defined provisions by the Code for peening and inspection
relief for upper heads with Alloy 690 penetration nozzles which provide
alternatives to the use of current requirements and provide
clarification or relaxation of existing conditions. Therefore, the NRC
concludes the proposed incorporation by reference of ASME BPV Code Case
N-729-6, as conditioned, into Sec. 50.55a is not a backfit.
16. Revise Sec. 50.55a(g)(6)(ii)(F), ``Examination requirements
for Class 1 piping and nozzle dissimilar metal butt welds.'' On
November 7, 2016, the ASME approved the fifth revision of ASME BPV Code
Case N-770 (N-770-5). The NRC proposes to update the requirements of
Sec. 50.55a(g)(6)(ii)(F) to require licensees to implement ASME BPV
Code Case N-770-5, with conditions. The ASME BPV Code Case N-770-5
contains similar baseline and ISI requirements for unmitigated nickel-
alloy butt welds, and preservice and ISI requirements for mitigated
butt welds as N-770-2. However, N-770-5 also contains new provisions
which extend the inspection frequency for cold leg temperature
dissimilar metal butt welds greater than 14-inches in diameter to once
per interval not to exceed 13 years, define performance criteria and
examinations for welds mitigated by peening, and criteria for inservice
inspection requirements for excavate and weld repair PWSCC mitigations.
Minor changes were also made to address editorial issues, to correct
figures, or to add clarity. The NRC's proposed conditions on the use of
ASME BPV Code Case N-770-5 have been modified to address the changes in
the code case, clarify reporting requirements and address the
implementation of peening and excavate and weld repair PWSCC mitigation
techniques.
The current regulatory requirements for the examination of ASME
Class 1 piping and nozzle dissimilar metal butt welds that use nickel-
alloy materials are provided in Sec. 50.55a(g)(6)(ii)(F). This section
was first created by rulemaking, dated June 21, 2011 (76 FR 36232), to
require licensees to implement ASME BPV Code Case N-770-1, with
conditions. The NRC added Sec. 50.55a(g)(6)(ii)(F) to require
licensees to implement ASME BPV Code Case N-770-1, with conditions,
instead of the examinations previously required by the ASME BPV Code,
Section XI. The action did constitute a backfit; however, the NRC
concluded that imposition of ASME BPV Code Case N-770-1, as
conditioned, constituted an adequate protection backfit.
The GDC for nuclear power plants (appendix A to 10 CFR part 50) or,
as appropriate, similar requirements in the licensing basis for a
reactor facility, provide bases and requirements for NRC assessment of
the potential for, and consequences of, degradation of the RCPB. The
applicable GDC include GDC 14 (Reactor Coolant Pressure Boundary), GDC
31 (Fracture Prevention of Reactor Coolant Pressure Boundary) and GDC
32 (Inspection of Reactor Coolant Pressure Boundary). General Design
Criterion 14 specifies that the RCPB be designed, fabricated, erected,
and tested so as to have an extremely low probability of abnormal
leakage, of rapidly propagating failure, and of gross rupture. General
Design Criterion 31 specifies that the probability of rapidly
propagating fracture of the RCPB be minimized. General Design Criterion
32 specifies that components that are part of the RCPB have the
capability of being periodically inspected to assess their structural
and leak-tight integrity.
The NRC concludes that incorporation by reference of Code Case N-
770-5, as conditioned, into Sec. 50.55a as a mandatory requirement
will continue to ensure reasonable assurance of adequate protection of
public health and safety. Updating the regulations to require using
ASME BPV Code Case N-770-5, with conditions, ensures leakage would
likely not occur and potential flaws will be detected before they
challenge the structural or leak-tight integrity of these reactor
coolant pressure boundary piping welds. All current licensees of U.S.
pressurized water reactors will be required to implement ASME BPV Code
Case N-770-5, as conditioned. The Code Case N-770-5 provisions for the
examination requirements for ASME Class 1 piping and nozzle nickel-
alloy dissimilar metal butt welds are similar to those established
under ASME BPV Code Case N-770-2, as conditioned, however, Code Case N-
770-5 includes provisions for two additional PWSCC mitigation
techniques peening and excavate and weld repair along with requirements
for performance of these techniques and examination of welds mitigated
using them. Additionally, Code Case N-770-5 would allow for some
relaxation in the re-examination or deferral of certain welds. However,
the NRC's proposed condition would not allow this relaxation/deferral
of examination requirements. The proposed NRC conditions on Code Case
N-770-5 address newly defined provisions by the Code for examinations
and performance criteria for mitigation by peening, examinations for
mitigation by excavate and weld repair, and extension of the
examination frequency for certain cold leg temperature welds which
provide alternatives to the use of current requirements and provide
clarification or relaxation of existing conditions. The proposed
modification to the condition in Sec. 50.55a(g)(6)(ii)(F)(11) adds an
alternative method for meeting the condition. Therefore, the NRC
concludes the proposed incorporation by reference of ASME BPV Code Case
N-770-5, as conditioned, into Sec. 50.55a is not a backfit.
ASME OM Code
1. Revise the introductory text of paragraph (b)(3) to reference
the 1995 Edition through the latest edition and addenda of the ASME OM
Code incorporated by reference in Sec. 50.55a(a)(1)(iv), and to
include Appendix IV of the ASME OM Code in the list of mandatory
appendices incorporated by reference in Sec. 50.55a. The revision of
Sec. 50.55a to incorporate by reference updated editions of the ASME
OM Code is consistent with long-standing NRC policy and does not
constitute a backfit.
[[Page 56189]]
2. Revise Sec. 50.55a(b)(3)(ii) to specify that the condition on
MOV testing applies to the latest edition and addenda of the ASME OM
Code incorporated by reference in Sec. 50.55a(a)(1)(iv). This will
allow future rulemakings to revise Sec. 50.55a(a)(1)(iv) to
incorporate the latest edition of the ASME OM Code without the need to
revise Sec. 50.55a(b)(3)(ii). This is an administrative change to
simplify future rulemakings and, therefore, is not a backfit.
3. Revise Sec. 50.55a(b)(3)(iv) to (1) accept the use of Appendix
II in the 2017 Edition of the ASME OM Code without conditions; (2)
update Sec. 50.55a(b)(3)(iv) to apply Table II to Appendix II of the
ASME OM Code, 2003 Addenda through the 2015 Edition; and (3) remove the
outdated conditions in paragraphs (A) through (D) of Sec.
50.55a(b)(3)(iv). These changes reflect improvements to Appendix II in
the 2017 Edition of the ASME OM Code, and the removal of outdated
conditions on previous editions and addenda of the ASME OM Code. The
relaxation of conditions in Sec. 50.55a(b)(3)(iv) to reflect the
updated ASME OM Code is not a backfit.
4. Revise Sec. 50.55a(b)(3)(viii) to specify that the condition on
Subsection ISTE applies to the latest edition and addenda of the ASME
OM Code incorporated by reference in Sec. 50.55a(a)(1)(iv). This will
allow future rulemakings to revise Sec. 50.55a(a)(1)(iv) to
incorporate the latest edition of the ASME OM Code without the need to
revise Sec. 50.55a(b)(3)(viii). This is an administrative change to
simplify future rulemakings and, therefore, is not a backfit.
5. Revise Sec. 50.55a(b)(3)(ix) to specify that Subsection ISTF of
the ASME OM Code, 2017 Edition, is acceptable without conditions, and
that licensees applying Subsection ISTF in the 2015 Edition of the ASME
OM Code shall satisfy the requirements of Appendix V of the ASME OM
Code. Subsection ISTF in the 2017 Edition of the ASME OM Code has
incorporated the provisions from Appendix V such that its reference to
Subsection ISTF in the 2017 Edition of the ASME OM Code is not
necessary. This is an update to the condition to apply to the 2015
Edition (in addition to the 2012 Edition), and a relaxation to remove
the applicability of the condition to the 2017 Edition of the ASME OM
Code. Therefore, the update to this condition is not a backfit.
6. Revise Sec. 50.55a(b)(3)(xi) for the implementation of
paragraph ISTC-3700 on valve position indication in the ASME OM Code to
apply to the 2012 Edition through the latest edition and addenda of the
ASME OM Code incorporated by reference in Sec. 50.55a(a)(1)(iv). This
will allow future rulemakings to revise Sec. 50.55a(a)(1)(iv) to
incorporate the latest edition of the ASME OM Code without the need to
revise Sec. 50.55a(b)(3)(xi). In addition, the NRC proposes to clarify
that this condition applies to all valves with remote position
indicators within the scope of Subsection ISTC and all mandatory
appendices. This is an administrative change to simplify future
rulemakings and clarify the condition and, therefore, is not a backfit.
7. Establish Sec. 50.55a(b)(3)(xii) to require the application of
the AOV provisions in Appendix IV of the 2017 Edition of the ASME OM
Code, when implementing the ASME OM Code, 2015 Edition. This will
provide consistency between the implementation of these two new
editions of the ASME OM Code and, therefore, this condition is not a
backfit.
8. Revise Sec. 50.55a(f)(4)(i) and (ii) to relax the time schedule
for complying with the latest edition and addenda of the ASME OM Code
for the initial and successive IST programs from 12 months to 18
months. This relaxation of the time schedule for the IST programs is
not a backfit.
9. Add Sec. 50.55a(f)(7), ``Inservice Testing Reporting
Requirements,'' to state that IST Plans and interim IST Plan updates
for pumps and valves; and IST Plans and interim Plan updates related to
snubber examination and testing must be submitted to the NRC. This
requirement is currently in the ASME OM Code, but the ASME is planning
to remove this from the ASME OM Code in the future. Therefore, this is
not a backfit because the NRC is not imposing a new requirement.
10. Revise Sec. 50.55a(g)(4)(i) and (ii) to relax the time
schedule for complying with the latest edition and addenda of the ASME
BPV Code for the initial and successive ISI programs from 12 months to
18 months. This relaxation of the time schedule for the ISI programs is
not a backfit.
Conclusion
The NRC finds that incorporation by reference into Sec. 50.55a of
the 2015 and 2017 Editions of Section III, Division 1, of the ASME BPV
Code subject to the identified conditions; the 2015 and 2017 Edition of
Section XI, Division 1, of the ASME BPV Code, subject to the identified
conditions; the 2015 and 2017 Editions of the ASME OM Code subject to
the identified conditions, and the two Code Cases N-729-6 and N-770-5
subject to identified conditions does not constitute backfitting or
represent an inconsistency with any issue finality provisions in 10 CFR
part 52.
XIV. Regulatory Flexibility Certification
Under the Regulatory Flexibility Act of 1980 (5 U.S.C. 605(b)), the
NRC certifies that this proposed rule does not impose a significant
economical impact on a substantial number of small entities. This
proposed rule affects only the licensing and operation of commercial
nuclear power plants. A licensee who is a subsidiary of a large entity
does not qualify as a small entity. The companies that own these plants
are not ``small entities'' as defined in the Regulatory Flexibility Act
or the size standards established by the NRC (Sec. 2.810), as the
companies:
Provide services that are not engaged in manufacturing,
and have average gross receipts of more than $6.5 million over their
last 3 completed fiscal years, and have more than 500 employees;
Are not governments of a city, county, town, township or
village;
Are not school districts or special districts with
populations of less than 50; and
Are not small educational institutions.
XV. Availability of Documents
The NRC is making the documents identified in Table 1 available to
interested persons through one or more of the following methods, as
indicated. To access documents related to this action, see the
ADDRESSES section of this document.
[[Page 56190]]
Table 1--Availability of Documents
------------------------------------------------------------------------
Document ADAMS accession No.
------------------------------------------------------------------------
Proposed Rule Documents:
Regulatory Analysis (includes ML18150A267.
backfitting discussion in Appendix A).
Related Documents:
Letter from Brian Thomas, NRC, to ML17310A186.
William Berger, ASME; ``Public Access
to Material the NRC Seeks to
Incorporate by Reference into its
Regulations-Revised Request;'' January
8, 2018.
Email from Christian Sanna, ASME, to ML18157A113.
Brian Thomas, NRC; May 30, 2018.
Memorandum from Wallace Norris, NRC, to ML14245A003.
David Rudland, NRC; ``Summary of
August 22, 2014, Public Meeting
Between ASME and NRC--Information
Exchange;'' September 8, 2014.
Letter from John Lubinski, NRC, to ML14261A051.
Kevin Ennis, ASME; ``NRC Information
Notice 2014-07 Regarding Inspection of
Containment Leak-Chase Channels;''
March 3, 2015.
Letter from Ralph Hill, ASME, to John ML15106A627.
Lubinski, NRC; ``ASME Code, Section XI
Actions to Address Requirements for
Examination of Containment Leak-Chase
Channels;'' April 13, 2015.
NUREG/CR-6654, ``A Study of Air- ML003691872.
Operated Valves in U.S. Nuclear Power
Plants,'' February 2000.
NRC Generic Letter 88-14, ``Instrument ML031130440.
Air Supply System Problems Affecting
Safety-Related Equipment,'' August
1988.
NRC Regulatory Issue Summary 2000-03, ML003686003.
``Resolution of Generic Safety Issue
(GSI) 158, `Performance of Safety
Related Power-Operated Valves Under
Design-Basis Conditions','' March 2000.
NRC Information Notice 1986-050, ML031220684.
``Inadequate Testing To Detect
Failures of Safety-Related Pneumatic
Components or Systems;'' June 1986.
NRC Information Notice 1985-084, ML031180213.
``Inadequate Inservice Testing of Main
Steam Isolation Valves,'' October 1985.
NRC Information Notice 1996-048, ML031060093.
``Motor-Operated Valve Performance
Issues,'' August 1996.
NRC Information Notice 1996-048, ML031050431.
Supplement 1, ``Motor-Operated Valve
Performance Issues,'' July 1998.
NRC Information Notice 1998-13, ``Post- ML031050237.
Refueling Outage Reactor Pressure
Vessel Leakage Testing Before Core
Criticality,'' April 1998.
NRC Information Notice 2014-07, ML14070A114.
``Degradation of Leak-Chase Channel
Systems For Floor Welds Of Metal
Containment Shell And Concrete
Containment Metallic Liner,'' May 2014.
NRC Information Notice 2015-13, ``Main ML15252A122.
Steam Isolation Valve Failure
Events,'' December 2015.
NRC Inspection Report 50-254/97027, ML15216A276.
March 1998.
NUREG-0800, Section 5.4.2.2, Revision ML052340627.
1, ``Steam Generator Tube Inservice
Inspection,'' July 1981.
NUREG-0800, Section 5.4.2.2, Revision ML070380194.
2, ``Steam Generator Program,'' March
2007.
NRC Regulatory Guide 1.83, Revision 1, ML003740256.
``Inservice Inspection of Pressurized
Water Reactor Steam Generator Tubes,''
July 1975 (withdrawn in 2009).
RG 1.147, ``Inservice Inspection Code ML18114A225.
Case Acceptability, ASME Section XI,
Division 1,'' Revision 19.
NUREG/CR-7153, ``Expanded Materials ML14279A321.
Degradation Assessment (EMDA),'' ML14279A461.
October 2014. ML14279A349 .
ML14279A430.
ML14279A331.
NUREG-0619, Rev. 1, ``BWR Feedwater ML031600712.
Nozzle and Control Rod Drive Return
Line Nozzle Cracking: Resolution of
Generic Technical Activity A-10
(Technical Report),'' November 1980.
NUREG-1801, Rev 2, ``Generic Aging ML103490041.
Lessons Learned (GALL) Report,''
December 2010.
NUREG-1800, Rev. 2, ``Standard Review ML103490036.
Plan for Review of License Renewal
Applications for Nuclear Power
Plants,'' December 2010.
NUREG-2191, ``Generic Aging Lessons ML17187A031.
Learned for Subsequent License Renewal ML17187A204.
(GALL-SLR) Report,'' July 2017.
NUREG-1950, ``Disposition of Public ML11116A062.
Comments and Technical Bases for
Changes in the License Renewal
Guidance Documents NUREG-1801 and
NUREG-1800,'' April 2011.
NUREG/CR-6933, ``Assessment of Crack ML071020410.
Detection in Heavy-Walled Cast ML071020414.
Stainless Steel Piping Welds Using
Advanced Low-Frequency Ultrasonic
Methods,'' March 2007.
NUREG/CR-7122, ``An Evaluation of ML12087A004.
Ultrasonic Phased Array Testing for
Cast Austenitic Stainless Steel
Pressurizer Surge Line Piping Welds,''
March 2012.
NUREG-2192, ``Standard Review Plan for ML17188A158.
Review of Subsequent License Renewal
Applications for Nuclear Power
Plants,'' July 2017.
Gupta KK, Hoffmann CL, Hamilton AM, http://
DeLose F. Fracture Toughness of proceedings.asmedigitalcol
Pressure Boundary Steels With Higher lection.asme.org/
Yield Strength. ASME. ASME Pressure proceeding.aspx?articleid=
Vessels and Piping Conference, ASME 1619041.
2010 Pressure Vessels and Piping
Conference: Volume 7 ():45-58.
doi:10.1115/PVP2010-25214.
ASME Codes, Standards, and Code Cases:
ASME BPV Code, Section III, Division 1: http://go.asme.org/NRC-
2015 Edition and 2017 Edition. ASME.
[[Page 56191]]
ASME BPV Code, Section XI, Division 1: http://go.asme.org/NRC-
2011a Addenda, 2013 Edition, 2015 ASME.
Edition, and 2017 Edition.
ASME OM Code, Division 1: 2015 Edition http://go.asme.org/NRC-
and 2017 Edition. ASME.
ASME BPV Code Case N-729-6............. http://go.asme.org/NRC-
ASME.
ASME BPV Code Case N-770-5............. http://go.asme.org/NRC-
ASME.
EPRI Topical Report:
EPRI Topical Report, '' Materials https://www.epri.com/#/
Reliability Program: Topical Report pages/product/
for Primary Water Stress Corrosion 000000003002009241/
Cracking Mitigation by Surface Stress ?lang=en.
Improvement (MRP-335, Revision 3-A),''
November 2016.
------------------------------------------------------------------------
Throughout the development of this rulemaking, the NRC may post
documents related to this proposed rule, including public comments, on
the Federal rulemaking website at http://www.regulations.gov under
Docket ID NRC-2016-0062. The Federal rulemaking website allows you to
receive alerts when changes or additions occur in a docket folder. To
subscribe: 1) Navigate to the docket folder for NRC-2011-0088; 2) click
the ``Sign up for Email Alerts'' link; and 3) enter your email address
and select how frequently you would like to receive emails (daily,
weekly, or monthly).
List of Subjects in 10 CFR Part 50
Administrative practice and procedure, Antitrust, Backfitting,
Classified information, Criminal penalties, Education, Fire prevention,
Fire protection, Incorporation by reference, Intergovernmental
relations, Nuclear power plants and reactors, Penalties, Radiation
protection, Reactor siting criteria, Reporting and recordkeeping
requirements, Whistleblowing.
For the reasons set forth in the preamble, and under the authority
of the Atomic Energy Act of 1954, as amended; the Energy Reorganization
Act of 1974, as amended; and 5 U.S.C. 553, the NRC proposes to adopt
the following amendments to 10 CFR part 50:
PART 50--DOMESTIC LICENSING OF PRODUCTION AND UTILIZATION
FACILITIES
0
1. The authority citation for part 50 continues to read as follows:
Authority: Atomic Energy Act of 1954, secs. 11, 101, 102, 103,
104, 105, 108, 122, 147, 149, 161, 181, 182, 183, 184, 185, 186,
187, 189, 223, 234 (42 U.S.C. 2014, 2131, 2132, 2133, 2134, 2135,
2138, 2152, 2167, 2169, 2201, 2231, 2232, 2233, 2234, 2235, 2236,
2237, 2239, 2273, 2282); Energy Reorganization Act of 1974, secs.
201, 202, 206, 211 (42 U.S.C. 5841, 5842, 5846, 5851); Nuclear Waste
Policy Act of 1982, sec. 306 (42 U.S.C. 10226); National
Environmental Policy Act of 1969 (42 U.S.C. 4332); 44 U.S.C. 3504
note; Sec. 109, Public Law 96-295, 94 Stat. 783.
0
2. In Sec. 50.55a:
0
a. In paragraph (a)(1)(i), remove the phrase ``(referred to herein as
ASME BPV Code)'';
0
b. In paragraph (a)(1)(i)(E)(16), remove the word ``and'';
0
c. In paragraph (a)(1)(i)(E)(17), at the end of the sentence, remove
the punctuation ``.'' and add in its place the punctuation ``,'';
0
d. Add paragraphs (a)(1)(i)(E)(18) and (19);
0
e. In paragraph (a)(1)(ii), remove the acronym ``BPV Code'' and add in
its place the words ``Boiler and Pressure Vessel Code'';
0
f. Revise paragraphs (a)(1)(ii)(C)(52) and (53);
0
g. Add paragraphs (a)(1)(ii)(C)(54) and (55);
0
h. Revise paragraphs (a)(1)(iii)(C) and (D);
0
i. In paragraph (a)(1)(iv), remove the phrase ``(various edition titles
referred to herein as ASME OM Code)'';
0
j. In paragraph (a)(1)(iv)(C)(1), at the end of the sentence, remove
the punctuation ``.'' and add in its place the punctuation ``,'';
0
k. Add paragraphs (a)(1)(iv)(C)(2) and (3), and paragraph (a)(4);
0
l. In paragraph (b)(1), remove the number ``2013'' and add in its place
the number ``2017'';
0
m. In paragraph (b)(1)(ii), in Table I, remove the number ``2013'' in
the last entry in the first column and add in its place the number
``2017'', and remove the word ``Note'' wherever it appears in the
second column and add in its place the word ``Footnote'';
0
n. In paragraph (b)(1)(iii), remove the phrase ``2008 Addenda''
wherever it appears and add in its place the phrase ``2017 Edition'';
0
o. In paragraph (b)(1)(v), remove the phrase ``the latest edition and
addenda'' and add in its place the phrase ``2009b Addenda of the 2007
Edition, where the NQA-1-1994 Edition is'';
0
p. In paragraph (b)(1)(vi), remove the phrase ``the latest edition and
addenda'' and add in its place the phrase ``all editions and addenda up
to and including the 2013 Edition'';
0
q. In paragraph (b)(1)(vii), remove the phrase ``the 2013 Edition'' and
add in its place the phrase ``all editions and addenda up to and
including the 2017 Edition'';
0
r. Add paragraphs (b)(1)(x) through (xii);
0
s. In paragraph (b)(2), remove the number ``2013'' and add in its place
the number ``2017'';
0
t. Remove and reserve paragraphs (b)(2)(vi), (vii), and (xvii);
0
u. Revise paragraph (b)(2)(ix) introductory text;
0
v. Add paragraph (b)(2)(ix)(K);
0
w. In paragraph (b)(2)(xviii)(D), remove the phrase ``and 2013 Edition
of Section XI of the ASME BPV Code'' and add in its place the phrase
``through the latest edition incorporated by reference in paragraph
(a)(1)(ii) of this section'';
0
x. Revise paragraph (b)(2)(xx)(B) and add paragraph (b)(2)(xx)(C);
0
y. Remove and reserve paragraph (b)(2)(xxi)(A), and add paragraph
(b)(2)(xxi)(B);
0
z. Revise paragraphs (b)(2)(xxv), (xxvi), (xxxii) and (xxxiv)
introductory text;
0
aa. In paragraph (b)(2)(xxxiv)(B) add the phrase ``of the 2013 and the
2015 Editions'' after the phrase ``Appendix U'';
0
bb. Revise paragraph (xxxv);
0
cc. In paragraph (b)(2)(xxxvi), remove the word ``Edition'' and add in
its place the phrase ``through 2017 Editions'';
0
dd. Add paragraphs (b)(2)(xxxviii) through (xlii);
0
ee. In paragraph (b)(3) introductory text, add the Roman numeral ``IV''
in sequential order, remove the phrase ``2012 Edition, as specified''
and add in its place the phrase ``latest edition and addenda of the
ASME OM Code incorporated by reference'' and revise the last sentence
in the paragraph;
0
ff. In paragraph (b)(3)(ii), remove the phrase ``, 2011 Addenda, and
2012 Edition'' and add in its place the phrase ``through the latest
edition and addenda
[[Page 56192]]
of the ASME OM Code incorporated by reference in paragraph (a)(1)(iv)
of this section'';
0
gg. Revise paragraph (b)(3)(iv) introductory text and remove and
reserve paragraphs (b)(3)(iv)(A) through (D);
0
hh. In paragraph (b)(3)(viii), remove the phrase ``, 2011 Addenda, and
2012 Edition'' and add in its place the phrase ``through the latest
edition and addenda of the ASME OM Code incorporated by reference in
paragraph (a)(1)(iv) of this section'';
0
ii. Revise paragraphs (b)(3)(ix) and (xi);
0
jj. Add paragraph (b)(3)(xii);
0
kk. In paragraphs (f)(4)(i) and (ii), remove the number ``12'' wherever
it appears and add in its place the number ``18'';
0
ll. Add paragraph (f)(7);
0
mm. In paragraph (g)(4) introductory text, remove the phrase ``,
subject to the condition listed in paragraph (b)(2)(vi) of this
section'';
0
nn. In paragraph (g)(4)(i), remove the number ``12'' wherever it
appears and add in its place the number ``18'';
0
oo. In paragraph (g)(4)(ii), in the first sentence remove the number
``12'' and add in its place the number ``18''; remove the date ``August
17, 2017'' wherever it appears and add in its place ``[DATE 75 DAYS
AFTER EFFECTIVE DATE OF FINAL RULE]'';
0
pp. Remove and reserve paragraph (g)(6)(ii)(C);
0
qq. Revise paragraphs (g)(6)(ii)(D)(1), (2) and (4), and add paragraphs
(g)(6)(ii)(D)(5) through (8);
0
rr. Revise paragraphs (g)(6)(ii)(F)(1) and (2), and remove and reserve
paragraph (g)(6)(ii)(F)(3);
0
ss. Revise paragraphs (g)(6)(ii)(F)(4), (6), (9) through (11), and
(13), and add paragraphs (g)(6)(ii)(F)(14) through (16).
The revisions and additions read as follows:
Sec. 50.55a Codes and standards.
(a)* * *
(1)* * *
(i)* * *
(E)* * *
(18) 2015 Edition (including Subsection NCA; and Division 1
subsections NB through NH and Appendices), and
(19) 2017 Edition (including Subsection NCA; and Division 1
subsections NB through NG and Appendices).
* * * * *
(ii)* * *
(C)* * *
(52) 2011a Addenda,
(53) 2013 Edition,
(54) 2015 Edition, and
(55) 2017 Edition.
* * * * *
(iii)* * *
(C) ASME BPV Code Case N-729-6. ASME BPV Code Case N-729-6,
``Alternative Examination Requirements for PWR Reactor Vessel Upper
Heads With Nozzles Having Pressure-Retaining Partial-Penetration Welds
Section XI, Division 1'' (Approval Date: March 3, 2016), with the
conditions in paragraph (g)(6)(ii)(D) of this section.
(D) ASME BPV Code Case N-770-5. ASME BPV Code Case N-770-5,
``Alternative Examination Requirements and Acceptance Standards for
Class 1 PWR Piping and Vessel Nozzle Butt Welds Fabricated with UNS
N06082 or UNS W86182 Weld Filler Material With or Without Application
of Listed Mitigation Activities Section XI, Division 1'' (Approval
Date: November 7, 2016), with the conditions in paragraph (g)(6)(ii)(F)
of this section.
* * * * *
(iv)* * *
(C)* * *
(2) 2015 Edition, and
(3) 2017 Edition.
* * * * *
(4) Electric Power Research Institute, Materials Reliability
Program, 3420 Hillview Avenue, Palo Alto, CA 94304-1338; telephone: 1-
650-855-2000; http://www.epri.com.
(i) ``Materials Reliability Program: Topical Report for Primary
Water Stress Corrosion Cracking Mitigation by Surface Stress
Improvement (MRP-335, Revision 3-A)'', EPRI approval date: November
2016.
(ii) [Reserved]
* * * * *
(b)* * *
(1)* * *
(x) Section III Condition: Visual examination of bolts, studs and
nuts. Applicants or licensees applying the provisions of NB-2582, NC-
2582, ND-2582, NE-2582, NF-2582, NG-2582 in the 2017 Edition of Section
III, must apply paragraphs (b)(1)(x)(A) through (B) of this section.
(A) Visual examination of bolts, studs, and nuts: First provision.
When applying the provisions of NB-2582, NC-2582, ND-2582, NE-2582, NF-
2582, NG-2582 in the 2017 Edition of Section III, the visual
examinations are required to be performed in accordance with procedures
qualified to NB-5100, NC-5100, ND-5100, NE-5100, NF-5100, NG-5100 and
performed by personnel qualified in accordance with NB-5500, NC-5500,
ND-5500, NE-5500, NF-5500, and NG-5500.
(B) Visual examination of bolts, studs, and nuts: Second provision.
When applying the provisions of NB-2582, NC-2582, ND-2582, NE-2582, NF-
2582, NG-2582 in the 2017 Edition of Section III, the acceptance
criteria from NB-2582, NC-2582, ND-2582, NE-2582, NF-2582, NG-2582 in
the 2015 Edition of Section III shall be used.
(xi) Section III condition: Mandatory Appendix XXVI. When applying
the 2015 and 2017 Editions of Section III, Mandatory Appendix XXVI,
``Rules for Construction of Class 3 Buried Polyethylene Pressure
Piping,'' applicants or licensees must meet the following conditions:
(A) Mandatory Appendix XXVI: First provision. When performing
fusing procedure qualification tests and operator performance
qualification tests in accordance with XXVI-4330 and XXVI-4340 the
following essential variables shall be used for the performance
qualification tests of butt fusion joints:
(1) Joint Type: A change in the type of joint from that qualified,
except that a square butt joint qualifies as a mitered joint.
(2) Pipe Surface Alignment: A change in the pipe outside diameter
(O.D.) surface misalignment of more than 10 percent of the wall
thickness of the thinner member to be fused.
(3) PE Material: Each lot of polyethylene source material to be
used in production (XXVI-2310(c)).
(4) Wall Thickness: Each thickness to be fused in production (XXVI-
2310(c)).
(5) Diameter: Each diameter to be fused in production (XXVI-
2310(c)).
(6) Cross-sectional Area: Each combination of thickness and
diameter (XXVI-2310(c)).
(7) Position: Maximum machine carriage slope when greater than 20
degrees from horizontal (XXVI-4321(c)).
(8) Heater Surface Temperature: A change in the heater surface
temperature to a value beyond the range tested (XXVI-2321).
(9) Ambient Temperature: A change in ambient temperature to less
than 50 [deg]F (10 [deg]C) or greater than 125 [deg]F (52 [deg]C)
(XXVI-4412(b)).
(10) Interfacial Pressure: A change in interfacial pressure to a
value beyond the range tested (XXVI-2321).
(11) Decrease in Melt Bead Width: A decrease in melt bead size from
that qualified.
(12) Increase in Heater Removal Time: An increase in heater plate
removal time from that qualified.
(13) Decrease in Cool-down Time: A decrease in the cooling time at
pressure from that qualified.
(14) Fusing Machine Carriage Model: A change in the fusing machine
carriage model from that tested (XXVI-2310(d)).
[[Page 56193]]
(B) Mandatory Appendix XXVI: Second provision. When performing
qualification tests of butt fusion joints in accordance with XXVI-4342,
both the bend test and the high speed tensile impact test shall be
successfully completed.
(C) Mandatory Appendix XXVI: Third provision. When performing
fusing procedure qualification tests and operator performance
qualification tests in accordance with 2017 Edition of BPV Code Section
III XXVI-4330 and XXVI-4340, the following essential variables shall be
used for the performance qualification tests of electrofusion joints:
(1) Joint Design: A change in the design of an electrofusion joint.
(2) Fit-up Gap: An increase in the maximum radial fit-up gap
qualified.
(3) Pipe PE Material: A change in the PE designation or cell
classification of the pipe from that tested (XXVI-2322(a)).
(4) Fitting PE Material: A change in the manufacturing facility or
production lot from that tested (XXVI-2322(b)).
(5) Pipe Wall Thickness: Each thickness to be fused in production
(XXVI-2310(c)).
(6) Fitting Manufacturer: A change in fitting manufacturer.
(7) Pipe Diameter: Each diameter to be fused in production (XXVI-
2310(c)).
(8) Cool-down Time: A decrease in the cool time at pressure from
that qualified.
(9) Fusion Voltage: A change in fusion voltage.
(10) Nominal Fusion Time: A change in the nominal fusion time.
(11) Material Temperature Range: A change in material fusing
temperature beyond the range qualified.
(12) Power Supply: A change in the make or model of electrofusion
control box (XXVI-2310(f)).
(13) Power Cord: A change in power cord material, length, or
diameter that reduces current at the coil to below the minimum
qualified.
(14) Processor: A change in the manufacturer or model number of the
processor. (XXVI-2310(f)).
(15) Saddle Clamp: A change in the type of saddle clamp.
(16) Scraping Device: A change from a clean peeling scraping tool
to any other type of tool.
(D) Mandatory Appendix XXVI: Fourth provision. Performance of crush
tests in accordance with 2017 BPV Code Section III XXVI-2332(a) and
XXVI-2332(b) and electrofusion bend tests in accordance with 2017 BPV
Code Section III XXVI-2332(b) are required to qualify fusing procedures
for electrofusion joints in polyethylene piping installed in accordance
with 2017 Edition of ASME BPV Code Section III, Mandatory Appendix
XXVI.
(E) Mandatory Appendix XXVI: Fifth provision. Electrofusion saddle
fittings and electrofusion saddle joints are not permitted for use.
Only full 360-degree seamless sleeve electrofusion couplings and full
360-degree electrofusion socket joints are permitted.
(xii) Section III condition: Certifying Engineer. When applying the
2017 and later editions of ASME BPV Code Section III, the NRC does not
permit applicants and licensees to use a certifying engineer in lieu of
a registered professional engineer for Code-related activities that are
applicable to U.S. nuclear facilities regulated by the NRC.
(2)* * *
(ix) Section XI condition: Metal containment examinations.
Applicants or licensees applying Subsection IWE, 1992 Edition with the
1992 Addenda, or the 1995 Edition with the 1996 Addenda, must satisfy
the requirements of paragraphs (b)(2)(ix)(A) through (E) and
(b)(2)(ix)(K) of this section. Applicants or licensees applying
Subsection IWE, 1998 Edition through the 2001 Edition with the 2003
Addenda, must satisfy the requirements of paragraphs (b)(2)(ix)(A) and
(B) and (b)(2)(ix)(F) through (I) and (b)(2)(ix)(K) of this section.
Applicants or licensees applying Subsection IWE, 2004 Edition, up to
and including the 2005 Addenda, must satisfy the requirements of
paragraphs (b)(2)(ix)(A) and (B) and (b)(2)(ix)(F) through (H) and
(b)(2)(ix)(K) of this section. Applicants or licensees applying
Subsection IWE, 2004 Edition with the 2006 Addenda, must satisfy the
requirements of paragraphs (b)(2)(ix)(A)(2) and (b)(2)(ix)(B) and
(b)(2)(ix)(K) of this section. Applicants or licensees applying
Subsection IWE, 2007 Edition through the 2015 Edition, must satisfy the
requirements of paragraphs (b)(2)(ix)(A)(2) and (b)(2)(ix)(B) and (J)
and (K) of this section. Applicants or licensees applying Subsection
IWE, 2017 Edition, must satisfy the requirements of paragraphs
(b)(2)(ix)(A)(2) and (b)(2)(ix)(B) and (J) of this section.
* * * * *
(K) Metal Containment Examinations: Eleventh provision. A general
visual examination of containment leak chase channel moisture barriers
must be performed once each interval, in accordance with the completion
percentages in Table IWE 2411 1 of the 2017 Edition. Examination shall
include the moisture barrier materials (caulking, gaskets, coatings,
etc.) that prevent water from accessing the embedded containment liner
within the leak chase channel system. Caps of stub tubes extending
above the concrete floor interface may be inspected, provided the
configuration of the cap functions as a moisture barrier as described
previously. Leak chase channel system closures need not be disassembled
for performance of examinations if the moisture barrier material is
clearly visible without disassembly, or coatings are intact. The
closures are acceptable if no damage or degradation exists that would
allow intrusion of moisture against inaccessible surfaces of the metal
containment shell or liner within the leak chase channel system.
Examinations that identify flaws or relevant conditions shall be
extended in accordance with paragraph IWE 2430 of the 2017 Edition.
(xx)* * *
(B) System leakage tests: Second provision. The nondestructive
examination method and acceptance criteria of the 1992 or later of
Section III shall be met when performing system leakage tests (in lieu
of a hydrostatic test) in accordance with IWA-4520 after repair and
replacement activities performed by welding or brazing on a pressure
retaining boundary using the 2003 Addenda through the latest edition
and addenda of Section XI incorporated by reference in paragraph
(a)(1)(ii) of this section. The nondestructive examination and pressure
testing may be performed using procedures and personnel meeting the
requirements of the licensee's/applicant's current ISI code of record.
(C) Section XI condition: System leakage tests: Third provision.
The use of the provisions for an alternative BWR pressure test at
reduced pressure to satisfy IWA-4540 requirements as described in IWA-
5213(b)(2), IWB-5210(c) and IWB-5221(d) of Section XI, 2017 Edition may
be used subject to the following conditions:
(1) The use of nuclear heat to conduct the BWR Class 1 system
leakage test is prohibited (i.e., the reactor must be in a non-critical
state), except during refueling outages in which the ASME Section XI
Category B-P pressure test has already been performed, or at the end of
mid-cycle maintenance outages fourteen (14) days or less in duration.
(2) In lieu of the test condition holding time of IWA-5213(b)(2),
after pressurization to test conditions, and before the visual
examinations commence, the holding time shall be 1 hour for non-
insulated components.
* * * * *
(xxi)* * *
(A) [Reserved]
[[Page 56194]]
(B) Section XI condition: Table IWB-2500-1 examination. Use of the
provisions of IWB-2500(f) and (g) and Table IWB-2500-1 Notes 6 and 7 of
the 2017 Edition of ASME Section XI for examination of Examination
Category B-D Item Numbers B3.90 and B3.100 shall be subject to the
following conditions:
(1) A plant-specific evaluation demonstrating the criteria of IWB-
2500(f) are met must be maintained in accordance with IWA-1400(l).
(2) The use of the provisions of IWB-2500(f) and Table IWB-2500-1
Note 6 for examination of Examination Category B-D Item Numbers B3.90
is prohibited for plants with renewed licenses in accordance with 10
CFR part 54.
(3) The provisions of IWB-2500(g) and Table IWB-2500-1 Notes 6 and
7 for examination of Examination Category B-D Item Numbers B3.90 and
B3.100 shall not be used to eliminate the preservice or inservice
volumetric examination of plants with a Combined Operating License
pursuant to 10 CFR part 52, or a plant that receives its operating
license after October 22, 2015.
* * * * *
(xxv) Section XI condition: Mitigation of defects by modification.
Use of the provisions of IWA-4340 shall be subject to the following
conditions:
(A) Mitigation of defects by modification: First provision. The use
of the provisions for mitigation of defects by modification in IWA-4340
of Section XI 2001 Edition through the 2010 Addenda, is prohibited.
(B) Mitigation of defects by modification: Second provision. The
use of the provisions for mitigation of defects by modification in IWA-
4340 of Section XI 2011 Edition through the 2017 Edition may be used
subject to the following conditions:
(1) The use of the provisions in IWA 4340 to mitigate crack-like
defects or those associated with flow accelerated corrosion are
prohibited.
(2) The design of a modification that mitigates a defect shall
incorporate a loss of material rate either 2 times the actual measured
corrosion rate in that pipe location (established based on wall
thickness measurements conducted at least twice in two prior
consecutive or nonconsecutive refueling outage cycles in the 10 year
period prior to installation of the modification), or 4 times the
estimated maximum corrosion rate for the piping system.
(3) The Owner shall perform a wall thickness examination in the
vicinity of the modification and relevant pipe base metal during each
refueling outage cycle to detect propagation of the flaw into the
material credited for structural integrity of the item unless the
examinations in the two refueling outage cycles subsequent to the
installation of the modification are capable of validating the
projected flaw growth.
(xxvi) Section XI condition: Pressure testing Class 1, 2, and 3
mechanical joints. When using the 2001 Edition through the latest
edition and addenda incorporated by reference in paragraph (a)(1)(ii)
of this section, licensees shall pressure test mechanical joints in
Class 1, 2, and 3 piping and components greater than NPS-1 which are
disassembled and reassembled during the performance of a Section XI
activity (e.g., repair/replacement activity), in accordance with IWA-
5211(a). The pressure test and examiners shall meet the requirements of
the licensee's/applicant's current ISI code of record.
* * * * *
(xxxii) Section XI condition: Summary report submittal. When using
ASME BPV Code, Section XI, 2010 Edition through the latest edition and
addenda incorporated by reference in paragraph (a)(1)(ii) of this
section, Summary Reports and Owner's Activity Reports described in IWA-
6230 must be submitted to the NRC. Preservice inspection reports for
examinations prior to commercial service shall be submitted prior to
the date of placement of the unit into commercial service. For
preservice and inservice examinations performed following placement of
the unit into commercial service, reports shall be submitted within 90
calendar days of the completion of each refueling outage.
* * * * *
(xxxiv) Section XI condition: Nonmandatory Appendix U. When using
Nonmandatory Appendix U of the ASME BPV Code, Section XI, 2013 Edition
through the latest edition incorporated by reference in paragraph
(a)(1)(ii) of this section, the following conditions apply:
* * * * *
(xxxv) Section XI condition: Use of RTT0 in the
KIa and KIc equations.
(A) When using the 2013 Edition of the ASME BPV Code, Section XI,
Appendix A, paragraph A-4200, if T0 is available, then
RTT0 may be used in place of RTNDT for
applications using the KIc equation and the associated
KIc curve, but not for applications using the KIa
equation and the associated KIa curve.
(B) When using the 2015 Edition of the ASME BPV Code, Section XI,
Appendix A, paragraph A-4200 subparagraph (c) RTKIa shall be
defined as RTKIa = T0 + 90.267 exp(-0.003406T0).
* * * * *
(xxxviii) Section XI condition: ASME Code Section XI Appendix III
Supplement 2. Licensees applying the provisions of ASME Code Section XI
Appendix III Supplement 2, ``Welds in Cast Austenitic Materials,'' are
subject to the following conditions:
(A) ASME Code Section XI Appendix III Supplement 2: First
provision. In lieu of Paragraph (c)(1)(-c)(-2), licensees shall use a
search unit with a center frequency of 500 kHz with a tolerance of +/-
20 percent.
(B) ASME Code Section XI Appendix III Supplement 2: Second
provision. In lieu of Paragraph (c)(1)(-d), the search unit shall
produce angles including, but not limited to, 30 to 55 degrees with a
maximum increment of 5 degrees.
(xxxix) Section XI condition: Defect Removal. The use of the
provisions for removal of defects by welding or brazing in IWA-
4421(c)(1) and IWA-4421(c)(2) of Section XI, 2017 Edition may be used
subject to the following conditions:
(A) Defect removal requirements: First provision. The provisions of
subparagraph IWA 4421(c)(1) shall not be used to contain or isolate a
defective area without removal of the defect.
(B) Defect removal requirements: Second provision. The provisions
of subparagraph IWA 4421(c)(2) shall not be used for crack-like
defects.
(xl) Section XI condition: Prohibitions on use of IWB-3510.4(b).
The use of ASME BPV Code, Section XI, subparagraphs IWB-3510.4(b)(4)
and IWB-3510.4(b)(5) is prohibited.
(xli) Section XI condition: Preservice Volumetric and Surface
Examinations Acceptance. The use of the provisions for accepting flaws
by analytical evaluation during preservice inspection in IWB-3112(a)(3)
and IWC-3112(a)(3) of Section XI, 2013 Edition through the latest
edition and addenda incorporated by reference in paragraph (a)(1)(ii)
of this section is prohibited.
(xlii) Section XI condition: Steam Generator Nozzle-to-Component
welds and Reactor Vessel Nozzle-to-Component welds. Licensees applying
the provisions of Table IWB-2500-1, Examination Category B-F, Pressure
Retaining Dissimilar Metal Welds in Vessel Nozzles, Item B5.11 (NPS 4
or Larger Nozzle-to-Component Butt Welds) of the 2013 Edition through
the latest edition and addenda incorporated by reference in paragraph
(a)(1)(ii) of this section and Item B5.71 (NPS 4 or Larger Nozzle-to-
Component Butt Welds) of the 2011a Addenda through
[[Page 56195]]
the latest edition and addenda incorporated by reference in paragraph
(a)(1)(ii) of this section must also meet the following conditions:
(A) Ultrasonic examination procedures, equipment, and personnel
shall be qualified by performance demonstration in accordance with
Mandatory Appendix VIII.
(B) When applying the examination requirements of Figure IWB-2500-
8, the volumetric examination volume shall be extended to include 100
percent of the weld volume, except as provided in paragraph
(b)(2)(xlii)(B)(1) of this section:
(1) When the examination volume that can be qualified by
performance demonstration is less than 100 percent of the weld volume,
the licensee may ultrasonically examine the qualified volume and
perform a flaw evaluation of the largest hypothetical crack that could
exist in the volume and not be qualified for ultrasonic examination,
subject to prior NRC authorization in accordance with paragraph (z) of
this section.
(2) [Reserved]
(3)* * * When implementing the ASME OM Code, conditions are
applicable only as specified in the following paragraphs:
* * * * *
(iv) OM condition: Check valves (Appendix II). Licensees applying
Appendix II of the ASME OM Code, 2003 Addenda through the 2015 Edition,
is acceptable for use with the following requirements. Trending and
evaluation shall support the determination that the valve or group of
valves is capable of performing its intended function(s) over the
entire interval. At least one of the Appendix II condition monitoring
activities for a valve group shall be performed on each valve of the
group at approximate equal intervals not to exceed the maximum interval
shown in the following table:
* * * * *
(A through D) [Reserved]
* * * * *
(ix) OM condition: Subsection ISTF. Licensees applying Subsection
ISTF, 2012 Edition or 2015 Edition, shall satisfy the requirements of
Mandatory Appendix V, ``Pump Periodic Verification Test Program,'' of
the ASME OM Code in that edition. Subsection ISTF, 2011 Addenda, is
prohibited for use.
* * * * *
(xi) OM condition: Valve Position Indication. When implementing
paragraph ISTC-3700, ``Position Verification Testing,'' in the ASME OM
Code, 2012 Edition through the latest edition and addenda of the ASME
OM Code incorporated by reference in paragraph (a)(1)(iv) of this
section, licensees shall verify that valve operation is accurately
indicated by supplementing valve position indicating lights with other
indications, such as flow meters or other suitable instrumentation, to
provide assurance of proper obturator position for valves with remote
position indication within the scope of Subsection ISTC and all
mandatory appendices.
(xii) OM condition: Air-operated valves (Appendix IV). When
implementing ASME OM Code, 2015 Edition, licensees shall also apply the
provisions in Appendix IV, ``Preservice and Inservice Testing of Active
Pneumatically Operated Valve Assemblies in Nuclear Power Plants,'' of
the 2017 Edition of the ASME OM Code.
* * * * *
(f)* * *
(7) Inservice Testing Reporting Requirements. Inservice Testing
Program Test and Examination Plans (IST Plans) required by the ASME OM
Code must be submitted to the NRC in accordance with Sec. 50.4. All
required IST Plan submittals must be made within 90 days of their
implementation. Electronic submission is preferred. In addition to the
IST Plans for the preservice test period, initial inservice test
interval, and successive inservice test intervals specified in the ASME
OM Code, interim IST Plan updates that involve changes to the following
must be submitted:
(i) The edition and addenda of ASME OM Code that apply to required
tests and examinations;
(ii) The classification of components and boundaries of system
classification;
(iii) Identification of components subject to tests and
examination;
(iv) Identification of components exempt from testing or
examination;
(v) ASME OM Code requirements for components and the test or
examination to be performed;
(vi) ASME OM Code requirements for components that are not being
satisfied by the tests or examinations; and justification for
alternative tests or examinations;
(vii) ASME OM Code Cases planned for use and the extent of their
application; or
(viii) Test or examination frequency or schedule for performance of
tests and examinations, as applicable.
* * * * *
(g)* * *
(6)* * *
(ii)* * *
(C) [Reserved]
(D) Augmented ISI requirements: Reactor vessel head inspections--
(1) Implementation. Holders of operating licenses or combined licenses
for pressurized-water reactors as of or after [DATE 75 DAYS AFTER
EFFECTIVE DATE OF FINAL RULE] shall implement the requirements of ASME
BPV Code Case N-729-6 instead of ASME BPV Code Case N-729-4, subject to
the conditions specified in paragraphs (g)(6)(ii)(D)(2) through (8) of
this section, by no later than one year after [DATE 75 DAYS AFTER
EFFECTIVE DATE OF FINAL RULE]. All previous NRC-approved alternatives
from the requirements of paragraph (g)(6)(ii)(D) of this section remain
valid.
(2) Appendix I use. If Appendix I is used, Section I 3000 must be
implemented to define an alternative examination area or volume.
* * * * *
(4) Surface exam acceptance criteria. In addition to the
requirements of paragraph 3132.1(b) of ASME BPV Code Case N-729-6, a
component whose surface examination detects rounded indications greater
than allowed in paragraph NB-5352 in size on the partial-penetration or
associated fillet weld shall be classified as having an unacceptable
indication and corrected in accordance with the provisions of paragraph
3132.2 of ASME BPV Code Case N-729-6.
(5) Peening. In lieu of inspection requirements of Table 1, Items
B4.50 and B4.60, and all other requirements in ASME BPV Code Case N-
729-6 pertaining to peening, in order for a RPV upper head with nozzles
and associated J-groove welds mitigated by peening to obtain inspection
relief from the requirements of Table 1 for unmitigated heads, peening
must meet the performance criteria, qualification, and inspection
requirements stated in MRP-335, Revision 3-A, with the exception that a
plant-specific alternative request is not required and NRC condition
5.4 of MRP-335, Revision 3-A does not apply.
(6) Baseline Examinations. In lieu of the requirements for Note
7(c) the baseline volumetric and surface examination for plants with a
RPV Head with less than 8 EDY shall be performed by 2.25 reinspection
years (RIY) after initial startup not to exceed 8 years.
(7) Sister Plants. Note 10 of ASME BPV Code Case N-729-6 shall not
be implemented without prior NRC approval.
(8) Volumetric Leak Path. In lieu of paragraph 3200(b) requirement
for a surface examination of the partial penetration weld, a volumetric
leak path
[[Page 56196]]
assessment of the nozzle may be performed in accordance with Note 6 of
Table 1 of N-729-6.
* * * * *
(F) Augmented ISI requirements: Examination requirements for Class
1 piping and nozzle dissimilar-metal butt welds--(1) Implementation.
Holders of operating licenses or combined licenses for pressurized-
water reactors as of or after [DATE 75 DAYS AFTER EFFECTIVE DATE OF
FINAL RULE], shall implement the requirements of ASME BPV Code Case N-
770-5 instead of ASME BPV Code Case N-770-2, subject to the conditions
specified in paragraphs (g)(6)(ii)(F)(2) through (16) of this section,
by no later than one (1) year after [DATE 75 DAYS AFTER EFFECTIVE DATE
OF FINAL RULE]. All NRC authorized alternatives from previous versions
of paragraph (g)(6)(ii)(F) of this section remain applicable.
(2) Categorization. (i) Welds that have been mitigated by the
Mechanical Stress Improvement Process (MSIPTM) may be categorized as
Inspection Items D or E, as appropriate, provided the criteria in
Appendix I of the code case have been met.
(ii) In order to be categorized as peened welds, in lieu of
inspection category L requirements and inspections, welds must meet the
performance criteria, qualification and inspection requirements as
stated by MRP-335, Revision 3-A, with the exception that no plant-
specific alternative is required.
(iii) Other mitigated welds shall be identified as the appropriate
inspection item of the NRC authorized alternative or NRC-approved code
case for the mitigation type in Regulatory Guide 1.147.
(iv) All other butt welds that rely on Alloy 82/182 for structural
integrity shall be categorized as Inspection Items A-1, A-2, B-1 or B-
2, as appropriate.
(v) Paragraph -1100(e) of ASME BPV Code Case N-770-5 shall not be
used to exempt welds that rely on Alloy 82/182 for structural integrity
from any requirement of this section.
(3) [Reserved]
* * * * *
(4) Examination coverage. When implementing Paragraph -2500(a) of
ASME BPV Code Case N-770-5, essentially 100 percent of the required
volumetric examination coverage shall be obtained, including greater
than 90 percent of the volumetric examination coverage for
circumferential flaws. Licensees are prohibited from using Paragraphs -
2500(c) and -2500(d) of ASME BPV Code Case N-770-5 to meet examination
requirements.
* * * * *
(6) Reporting requirements. The licensee will promptly notify the
NRC regarding any volumetric examination of a mitigated weld that
detects growth of existing flaws in the required examination volume
that exceed the previous IWB-3600 flaw evaluations, new flaws, or any
indication in the weld overlay or excavate and weld repair material
characterized as stress corrosion cracking. Additionally the licensee
will submit to the NRC a report summarizing the evaluation, along with
inputs, methodologies, assumptions, and causes of the new flaw or flaw
growth within 30 days following plant startup.
* * * * *
(9) Deferrals. (i) The initial inservice volumetric examination of
optimized weld overlays, Inspection Item C-2, shall not be deferred.
(ii) Volumetric inspection of peened dissimilar metal butt welds
shall not be deferred.
(iii) For Inspection Item M-2, N-1 and N-2 welds the second
required inservice volumetric examination shall not be deferred.
(10) Examination technique. Note 14(b) of Table 1 and Note (b) of
Figure 5(a) of ASME BPV Code Case N-770-5 may only be implemented if
the requirements of Note 14(a) of Table 1 of ASME BPV Code Case N-770-5
cannot be met.
(11) Cast stainless steel. Examination of ASME BPV Code Class 1
piping and vessel nozzle butt welds involving cast stainless steel
materials, will be performed with Appendix VIII, Supplement 9
qualifications, or qualifications similar to Appendix VIII, Supplement
2 or 10 using cast stainless steel mockups no later than the next
scheduled weld examination after January 1, 2022, in accordance with
the requirements of Paragraph -2500(a) or, as an alternative, using
inspections that meet the requirements of ASME Code Case N-824 as
conditioned in Regulatory Guide 1.147.
* * * * *
(13) Encoded ultrasonic examination. Ultrasonic examinations of
non-mitigated or cracked mitigated dissimilar metal butt welds in the
reactor coolant pressure boundary must be performed in accordance with
the requirements of Table 1 for Inspection Item A-1, A-2, B-1, B-2, E,
F-2, J, K, N-1, N-2 and O for essentially 100 percent of the required
inspection volume using an encoded method.
(14) Excavate and weld repair cold leg. For cold leg temperature M-
2, N-1 and N-2 welds, initial volumetric inspection after application
of an excavate and weld repair (EWR) shall be performed during the
second refueling outage.
(15) Cracked excavate and weld repair. In lieu of the examination
requirements for cracked welds with 360 excavate and weld repairs,
Inspection Item N-1 of Table 1, welds shall be examined during the
first or second refueling outage following EWR. Examination volumes
that show no indication of crack growth or new cracking shall be
examined once each inspection interval thereafter.
(16) Partial arc excavate and weld repair. Inspection Item O cannot
be used without NRC review and approval.
* * * * *
Dated at Rockville, Maryland, this 16th day of October, 2018.
For the Nuclear Regulatory Commission.
Ho K. Nieh,
Director, Office of Nuclear Reactor Regulation.
[FR Doc. 2018-24076 Filed 11-8-18; 8:45 am]
BILLING CODE 7590-01-P