[Federal Register Volume 78, Number 96 (Friday, May 17, 2013)]
[Notices]
[Pages 29159-29162]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2013-11847]


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NUCLEAR REGULATORY COMMISSION

[NRC-2013-0038]


Electric Power Research Institute; Seismic Evaluation Guidance

AGENCY: Nuclear Regulatory Commission.

ACTION: Endorsement letter; issuance.

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SUMMARY: The U.S. Nuclear Regulatory Commission (NRC) is issuing an 
endorsement letter of Electric Power Research Institute (EPRI) Report, 
``Seismic Evaluation Guidance: EPRI Guidance for the Resolution of 
Fukushima Near-Term Task Force Recommendation 2.1: Seismic,'' Draft 
Report, hereafter referred to as the EPRI Guidance.

ADDRESSES: You may access information related to this document, which 
the NRC possesses and is publicly available, by searching on http://www.regulations.gov under Docket ID NRC-2013-0038.
     Federal Rulemaking Web site: Go to http://www.regulations.gov and search for Docket ID NRC-2013-0038. Address 
questions about NRC dockets to Carol Gallagher; telephone: 301-492-
3668; email: Carol.Gallagher@nrc.gov.
     NRC's Agencywide Documents Access and Management System 
(ADAMS): You may access publicly-available documents online in the NRC 
Library 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 PDR.Resources@nrc.gov. The NRC staff's endorsement 
letter of the EPRI Guidance is available under ADAMS Accession No. 
ML13106A331. The NRC staff's request for information dated March 12, 
2012, is available under ADAMS Accession No. ML12053A340.

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     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.

FOR FURTHER INFORMATION CONTACT: Ms. Lisa M. Regner, Japan Lessons-
Learned Project Directorate, Office of Nuclear Reactor Regulation, U.S. 
Nuclear Regulatory Commission, Washington, DC 20555-0001; telephone: 
301-415-1906; email: Lisa.Regner@nrc.gov.

SUPPLEMENTARY INFORMATION: 

I. Background Information

    This EPRI Guidance provides additional information, to be used in 
combination with the staff-endorsed Screening Prioritization and 
Implementation Details (SPID) report,\1\ on an acceptable strategy to 
implement interim actions in accordance with item (6) of the Requested 
Information in Enclosure 1 ``Recommendation 2.1: Seismic,'' of the NRC 
staff's request for information (Section 50.54(f) of Title 10 of the 
Code of Federal Regulations (10 CFR), (the 50.54(f) letter)), ``Request 
for Information Pursuant to 10 CFR 50.54(f) Regarding Recommendations 
2.1, 2.3, and 9.3, of the Near-Term Task Force Review of Insights from 
the Fukushima Dai-ichi Accident,'' dated March 12, 2012. In addition, 
in its April 9, 2013 letter,\2\ the Nuclear Energy Institute (NEI) 
requested modifications to the schedule established in the staff's 
50.54(f) letter. The NRC staff has found the schedule modifications to 
be acceptable since they account for completion of the EPRI central and 
eastern United States (CEUS) ground motion model (GMM) update, 
completion of potential interim actions provided in the EPRI Guidance, 
and limited available seismic resources.
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    \1\ The SPID report is available in the NRC's Agencywide 
Documents Access and Management System (ADAMS) under Accession No. 
ML12333A170. The staff endorsement letter for the SPID report is 
available in ADAMS under Accession No. ML12319A074.
    \2\ The NEI letter, with attachments, is available in ADAMS in a 
package with Accession No. ML13101A345.
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    The NRC issued the 50.54(f) letter following letter dated March 12, 
2012, regarding Recommendations 2.1, 2.3, and 9.3, of the Near-Term 
Task Force (NTTF) Review of Insights from the Fukushima Dai-ichi 
Accident.\3\ The NRC issued the 50.54(f) letter following the staff's 
evaluation of the earthquake and tsunami, and resulting nuclear 
accident, at the Fukushima Dai-ichi nuclear power plant in March 2011. 
Enclosure 1 to the 50.54(f) letter requests licensees and holders of 
construction permits under 10 CFR Part 50, ``Domestic Licensing of 
Production and Utilization Facilities,'' to reevaluate the seismic 
hazards at their sites using present-day NRC requirements and guidance, 
and to identify actions taken or planned to address plant-specific 
vulnerabilities associated with the updated seismic hazards. Based on 
this information, the NRC staff will determine if additional regulatory 
actions are necessary to protect against the updated hazards.
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    \3\ The NTTF Report is available under ADAMS Accession No. 
ML111861807. The 50.54(f) letter is available under ADAMS Accession 
No. ML12053A340.
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    By letter dated February 15, 2013, the NRC staff issued an 
endorsement letter, with clarifications, of EPRI-1025287, ``Seismic 
Evaluation Guidance: Screening, Prioritization, and Implementation 
Details (SPID) for the Resolution of Fukushima Near-Term Task Force 
Recommendation 2.1: Seismic,'' referred to as the SPID report. This 
SPID report describes strategies for the screening, prioritization, and 
implementation of seismic risk evaluations that are acceptable to the 
NRC staff, and will assist nuclear power reactor licensees when 
responding to Enclosure 1 of the 50.54(f) letter.
    By letter dated April 9, 2013, the NEI submitted additional 
guidance to be used to supplement the SPID report for NRC endorsement. 
The letter also documented the industry's proposed plan to update the 
GMM for CEUS plants, and proposed modifications to the schedule for 
plant seismic reevaluations established in the 50.54(f) letter. The NEI 
letter, the EPRI Guidance, and additional attachments addressing 
proposed schedule changes are available in ADAMS under package 
Accession No. ML13101A345.

II. Ground Motion Model

    The 50.54(f) letter requested that the licensees whose plants are 
located in the CEUS use NUREG-2115, ``Central and Eastern United States 
[CEUS] Seismic Source Characterization for Nuclear Facilities'' and the 
appropriate EPRI (2004, 2006) GMM to characterize the seismic hazard 
for their sites. The industry is currently completing a study to update 
the EPRI (2004, 2006) GMM based on current data and new ground motion 
prediction equations developed by seismic experts.
    The NRC staff has interacted with NEI, EPRI, and other stakeholders 
in public meetings since November 2012, for status updates on 
industry's efforts to update the CEUS GMM. By letter dated January 31, 
2013, the NEI transmitted the EPRI draft document, ``Draft--EPRI (2004, 
2006) Ground Motion Model (GMM) Review Project'' to the NRC, requesting 
review and approval by February 27, 2013. For the update of its earlier 
GMM, EPRI used a significant amount of additional data, conducted field 
investigations, and used more recent methods than were previously 
available. In performing the GMM update, EPRI has also addressed the 
concerns of an independent peer review panel, which is an important 
part of the Senior Seismic Hazard Analysis Committee (SSHAC) guidelines 
(these guidelines are discussed in NRC's NUREG 2117, ``Practical 
Implementation Guidelines for SSHAC Level 3 and 4 Hazard Studies''). 
Following a review of the NEI submittal, in a public meeting on 
February 28, 2013, the staff expressed concern with EPRI's treatment of 
uncertainty and the level of documentation in the proposed updated GMM. 
The staff formally documented these concerns by letter dated March 20, 
2013.
    Subsequently, in a public meeting on March 26, 2013, industry 
presented a revision of its updated EPRI GMM, which demonstrated 
significant progress toward addressing the staff's concerns with 
respect to the treatment of uncertainty. Industry also proposed a 
schedule, including further interactions with NRC staff, for completing 
the development and documentation of the updated EPRI GMM. In order to 
complete its update of the EPRI GMM and accompanying documentation, and 
to allow time for the development of site-specific seismic hazard 
curves, industry proposed a 6 month delay from the schedule outlined in 
the 50.54(f) letter for the submittal of the seismic hazard 
reevaluations for CEUS plants.
    The staff agrees that updated models, methods, and data will 
provide licensees with the most current information in order to perform 
the seismic hazard evaluations requested by the 50.54(f) letter.

III. EPRI Guidance

    The EPRI Guidance document provides licensees with information on 
the performance of an Expedited Seismic Evaluation Process. The 
Expedited Seismic Evaluation Process is a screening, evaluation, and 
equipment modification process to be conducted by licensees to provide 
additional seismic margin and expedite plant safety enhancements while 
more detailed and comprehensive plant seismic risk evaluations are 
being performed.
    The Expedited Seismic Evaluation Process evaluations would be 
conducted on plants with a new seismic hazard that exceeds their 
current seismic design basis, and necessary

[[Page 29161]]

modifications would be made to certain core and containment cooling 
components used during the initial plant coping time following a severe 
external event. The letter states that CEUS licensees will complete 
non-outage-related Expedited Seismic Evaluation Process equipment 
modifications by December 2016. Western United States (WUS) licensees 
will complete non-outage-related Expedited Seismic Evaluation Process 
equipment modifications by June 2018.
    After review of industry's proposed EPRI Guidance, the NRC staff 
believes that the evaluations and potential near-term equipment 
modifications associated with the Expedited Seismic Evaluation Process 
will provide an important demonstration of seismic margin and enhance 
plant safety while more detailed plant risk evaluations are being 
conducted by licensees. The staff further concludes that the seismic 
evaluation guidance for the EPRI Guidance provides an appropriate 
methodology for licensees to implement and complete the Expedited 
Seismic Evaluation Process according to the schedule provided in the 
letter.

IV. Schedule Modifications

    The NEI has proposed two adjustments to the seismic hazard 
reevaluations at nuclear power plant sites: (1) to complete the update 
of the EPRI GMM for the CEUS, and (2) to implement the EPRI Guidance. 
These proposed changes affect the schedule outlined in the 50.54(f) 
letter.
    First, the industry has requested additional time to complete the 
updated EPRI GMM project, including documentation and interactions with 
the NRC staff. The project documentation is scheduled to be submitted 
to the NRC on June 3, 2013. Pending approval by the staff, the CEUS 
licensees will use the updated model to complete the site-specific 
seismic hazard reevaluations specified in Enclosure 1 to the SPID 
guidance. Currently, the hazard submittals are requested by September 
2013; however, industry has requested to submit the hazard evaluations 
by March 31, 2014. The industry stated in its letter that it will not 
delay submittal of items 3.a. ``Description of Subsurface Materials and 
Properties,'' and 3.b. ``Development of Base Case Profiles and 
Nonlinear Material Properties'' of Section 4 of Enclosure 1 to the SPID 
guidance. Licensees intend to submit these items in September 2013 for 
the staff's review. This will allow the staff to begin its review in 
accordance with the original schedule and complete a significant 
portion of the Section 4 review on time.
    The staff finds that the schedule modifications discussed above for 
CEUS plants are acceptable because the updated GMM will provide the 
CEUS operating nuclear plant fleet with a model developed using the 
most recent data and methodologies available for their seismic hazard 
reevaluations. Additionally, the partial submittal in September 2013 
will allow the staff to complete a portion of its CEUS review as 
originally scheduled by the 50.54(f) letter.
    Second, the industry has requested modifications to the 50.54(f) 
letter schedule to allow for implementation of the EPRI Guidance 
interim actions for those nuclear power plants where the reevaluated 
seismic hazard exceeds the plant's design basis. These schedule 
modifications allow for completion of Expedited Seismic Evaluation 
Process for CEUS plants by December 2016, if the modifications do not 
require a plant shutdown to access equipment. For WUS plants, the 
Expedited Seismic Evaluation Process modifications will be completed by 
June 2018, if the modifications do not require a plant shutdown to 
access equipment.
    For plants requiring a seismic risk analysis (i.e., those with a 
reevaluated seismic hazard that exceeds the current seismic design 
basis), the 50.54(f) letter states that the staff will perform a 
prioritization for both the CEUS and WUS plants into two priority 
groups, and possibly a third, if needed. Under industry's proposed 
schedule, the higher priority CEUS plants will complete their risk 
evaluations by June 2017 (originally scheduled for October 2016). This 
delay is primarily due to the additional time needed to complete the 
EPRI GMM update project. The second group of CEUS plants will complete 
their risk evaluations by December 2019. This is about a two-year delay 
from the schedule specified in the 50.54(f) letter for the lower 
priority plants to complete their risk evaluations. Conversely, the 
letter proposes an earlier completion date of June 2017 for the risk 
evaluations for the higher priority WUS plants.
    The staff finds that the schedule modifications discussed above for 
CEUS and WUS nuclear power plants are acceptable, since the Expedited 
Seismic Evaluation Process provides for near-term seismic evaluations 
and expedited equipment modifications at the plants that will offer 
additional assurance that plants will operate safely during a beyond 
design basis seismic event. Furthermore, the schedule modifications 
account for limited seismic resources available to both the NRC and the 
industry. The schedule modifications provide for completion of the 
higher priority CEUS plant risk evaluations by the end of June 2017, 
which is not a significant extension of the original 50.54(f) letter 
schedule of October 2016. In addition, the schedule proposes an earlier 
completion date for the higher priority risk evaluations for the WUS 
plants.

V. Basis for Endorsement

    The NRC staff interacted with the stakeholders on development of 
the EPRI Guidance report with a focus on guidance on potential interim 
actions to be implemented for plants where the reevaluated seismic 
hazard exceeds the current seismic design basis. The EPRI Guidance 
report is the product of considerable interaction between the NRC, NEI, 
EPRI, and other stakeholders at five public meetings \4\ over a 5-month 
period. These interactions and the insights gained from the meetings 
allowed for the development of this document in a very short time 
frame. The meetings helped develop the expectations for how licensees 
would perform potential interim actions after updating their seismic 
hazard information. At each meeting, the NRC staff provided its 
comments on the current version of the EPRI Guidance and discussed with 
stakeholders subsequent proposed revisions to the document. This 
iterative process, over several months, resulted in the final version 
of the document. The NRC staff's endorsement of the EPRI Guidance is 
based on this cumulative development process resulting from the 
interactions between stakeholders and the NRC staff. This is the same 
process employed successfully in the development of the SPID guidance.
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    \4\ Public meetings were held on November 2 and 14 and December 
13, 2012; and February 14 and March 26, 2013.
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    The staff has determined that the EPRI Guidance will provide an 
important demonstration of seismic margin and enhanced plant safety 
through evaluations and potential near-term modifications of certain 
core and containment cooling equipment while more comprehensive plant 
seismic risk evaluations are being performed. The NRC staff also has 
determined that the schedule modifications provided in the NEI's April 
9, 2013, letter are acceptable because the schedule accounts for 
seismic resource limitations, EPRI's completion of the update to the 
GMM for the CEUS, and implementation of the EPRI Guidance evaluations 
and actions.

[[Page 29162]]

VI. Backfitting and Issue Finality

    This endorsement letter does not constitute backfitting as defined 
in 10 CFR 50.109, ``Backfitting'' (the Backfit Rule). This endorsement 
letter provides additional guidance on an acceptable method for 
implementing the interim actions described in item (6) of the Requested 
Information in Enclosure 1, ``Recommendation 2.1: Seismic,'' of the 
50.54(f) letter. Licensees and construction permit holders may 
voluntarily use the guidance in the EPRI Guidance to comply with the 
requested interim action portion of the 50.54(f) letter. Methods, 
analyses, or solutions that differ from those described in the EPRI 
Guidance report may be deemed acceptable if they provide sufficient 
basis and information for the NRC staff to verify that the proposed 
alternative is acceptable.

VII. Congressional Review Act

    This endorsement letter is a rule as designated in the 
Congressional Review Act (5 U.S.C. 801-808). The Office of Management 
and Budget has found that this is a major rule in accordance with the 
Congressional Review Act.

    Dated at Rockville, Maryland, this 7th day of May 2013.

    For the Nuclear Regulatory Commission.
Eric J. Leeds,
Director, Office of Nuclear Reactor Regulation.
[FR Doc. 2013-11847 Filed 5-16-13; 8:45 am]
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