[Federal Register Volume 72, Number 224 (Wednesday, November 21, 2007)]
[Notices]
[Pages 65610-65615]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: E7-22740]


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NUCLEAR REGULATORY COMMISSION


Notice of Availability on Model Safety Evaluation; Model No 
Significant Hazards Determination, and Model Application for Licensees 
That Wish to Adopt TSTF-478, Revision 2, ``BWR Technical Specification 
Changes that Implement the Revised Rule for Combustible Gas Control''

AGENCY: Nuclear Regulatory Commission.

ACTION: Notice of Availability.

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SUMMARY: Notice is hereby given that the staff of the Nuclear 
Regulatory Commission (NRC) has prepared a model safety evaluation (SE) 
and a model application related to the modification of containment 
combustible gas control requirements in technical specifications (TS) 
for Boiling Water Reactors (BWR). The NRC staff has also prepared a 
model no-significant-hazards-consideration (NSHC) determination related 
to this matter. The purpose of these models is to permit the NRC to 
efficiently process license amendment applications that propose to 
adopt TSTF-478, Revision 2, ``BWR Technical Specification Changes that 
Implement the Revised Rule for Combustible Gas Control.'' TSTF-478, 
Revision 2, deletes Standard Technical Specification (STS) 3.6.3.3, 
``Containment Atmosphere Dilution (CAD) System'' and modifies STS 
3.6.3.1, ``Drywell Cooling System Fans,'' in NUREG-1433, ``Standard 
Technical

[[Page 65611]]

Specifications General Electric Plants, BWR/4, Rev. 3,'' to establish 
TS for containment combustible gas control requirements as permitted by 
revised 10 CFR 50.44. Licensees of nuclear power reactors to which the 
models apply could then request amendments, confirming the 
applicability of the SE and NSHC determination to their plants.

DATES: The NRC staff issued a Federal Register Notice on October 11, 
2007 (72 FR 57970) that provided a model safety evaluation (SE), a 
model application, and a model no significant hazards consideration 
(NSHC) determination relating to licensee adoption of TSTF-478, 
Revision 2, ``BWR Technical Specification Changes that Implement the 
Revised Rule for Combustible Gas Control.'' The NRC staff hereby 
announces that the model SE and NSHC determination may be referenced in 
plant-specific applications to adopt the changes. The staff will post a 
model application on the NRC web site to assist licensees in using the 
consolidated line item improvement process (CLIIP).

FOR FURTHER INFORMATION CONTACT: Tim Kobetz, Mail Stop: O-12H2, 
Division of Inspection and Regional Support, Office of Nuclear Reactor 
Regulation, U.S. Nuclear Regulatory Commission, Washington, DC 20555-
0001, telephone 301-415-1932.

SUPPLEMENTARY INFORMATION: 

Background

    Regulatory Issue Summary 2000-06, ``Consolidated Line Item 
Improvement Process for Adopting Standard Technical Specification 
Changes for Power Reactors,'' was issued on March 20, 2000. The 
consolidated line item improvement process (CLIIP) is intended to 
improve the efficiency of NRC licensing processes by processing 
proposed changes to the standard technical specifications (STS) in a 
manner that supports subsequent license amendment applications. The 
CLIIP includes an opportunity for the public to comment on a proposed 
change to the STS after a preliminary assessment by the NRC staff and a 
finding that the change will likely be offered for adoption by 
licensees. The CLIIP directs the NRC staff to evaluate any comments 
received for a proposed change to NUREG-1433 and to either reconsider 
the change or announce the availability of the change for adoption by 
licensees.
    This notice contains changes proposed for incorporation into the 
standard technical specifications by owners group participants in the 
Technical Specification Task Force (TSTF) and is designated TSTF-478. 
TSTF-478, Revision 2 can be viewed on the NRC's web page utilizing the 
Agencywide Documents Access and Management System (ADAMS). The ADAMS 
accession number for TSTF-478, Revision 2, is ML071920140.
    TSTF-478, Revision 0, was originally submitted to the NRC on April 
25, 2005 (ADAMS Accession No. ML051170308). The NRC staff issued a 
Request for Additional Information (RAI) letter on November 9, 2006 
(ADAMS Accession No. ML062770089) and the TSTF provided an RAI Response 
letter dated February 7, 2007 (ADAMS Accession No. ML070380175). TSTF-
478, Revision 1, was submitted to the NRC on February 21, 2007 (ADAMS 
Accession No. ML070530490). The NRC made a final determination, and 
denied TSTF-478, Revision 1, on May 8, 2007 (ADAMS Accession No. 
ML071090368). TSTF-478, Revision 2, removes the parts of TSTF-478, 
Revision 1, that were considered unacceptable to NRC staff.
    It should be noted that TSTF-478, Revision 2, also proposes to 
revise the Bases for STS 3.6.3.2, ``Drywell Purge System'' in NUREG-
1434, ``Standard Technical Specifications General Electric Plants, BWR/
6, Rev. 3,'' by eliminating references to Design Basis Accidents while 
adding references to Accidents. This change was also listed in TSTF-
478, Revision 1, and the NRC staff found this modification to be 
acceptable (ADAMS Accession No. ML071090368). Licensees that wish to 
revise the Bases of TS 3.6.3.2, ``Drywell Purge System,'' may do so, 
without a plant-specific license amendment request, provided the 
requirements of 10 CFR 50.59 are met. As a result, modifications to the 
Bases are not included in the model safety evaluation or model 
application.

Applicability

    Licensees opting to apply for this TS change are responsible for 
reviewing the staff's evaluation, referencing the applicable technical 
justifications, and providing any necessary plant-specific information. 
To efficiently process the incoming license amendment applications, the 
NRC staff requests that each licensee applying for the changes 
addressed by TSTF-478, Revision 2, using the CLIIP, submit a license 
amendment request that adheres to the attached model application. 
Variations from the model application in this notice may require 
additional review by NRC staff, and may increase the time and resources 
needed for review. Significant variations from the model application, 
or inclusion of additional changes to the license, may result in staff 
rejection of the submittal. Each amendment application made in response 
to the notice of availability will be processed and noticed in 
accordance with applicable rules and NRC procedures.

Public Notices

    In a notice in the Federal Register dated October 11, 2007 (72 FR 
57970), the staff requested comment on the use of the CLIIP to process 
requests to revise the TS regarding TSTF-478, Revision 2. No comments 
were received. Licensees wishing to adopt the change must submit an 
application in accordance with applicable rules and other regulatory 
requirements. For each application the staff will publish a notice of 
consideration of issuance of amendment to facility operating licenses, 
a proposed no significant hazards consideration determination, and a 
notice of opportunity for a hearing. The staff will also publish a 
notice of issuance of an amendment to an operating license to announce 
the deletion of TS 3.6.3.3, ``Containment Atmosphere Dilution (CAD) 
System'' and the modification of TS 3.6.3.1, ``Drywell Cooling System 
Fans,'' for each plant that receives the requested change.

    Dated at Rockville, Maryland, this 14th of November 2007.

    For the Nuclear Regulatory Commission.

Timothy Kobetz,
Branch Chief, Technical Specifications Branch, Division of Inspections 
and Regional Support, Office of Nuclear Reactor Regulation.

Proposed Model Application for License Amendments Adopting TSTF-478, 
REV. 2, ``BWR Technical Specification Changes That Implement the 
Revised Rule for Combustible Gas Control''

U.S. Nuclear Regulatory Commission, Document Control Desk, Washington, 
DC 20555

SUBJECT: [Plant Name], Docket No. 50-----License Amendment Request for 
Adoption of TSTF-478, REV. 2, ``BWR Technical Specification Changes 
that Implement the Revised Rule for Combustible Gas Control''

    In accordance with the provisions of Section 50.90 of Title 10 of 
the Code of Federal Regulations (10CFR), [LICENSEE] is submitting a 
request for an amendment to the technical specifications (TS) for 
[PLANT NAME, UNIT NO.].
    The proposed amendment would delete TS 3.6.3.3, ``Containment

[[Page 65612]]

Atmosphere Dilution (CAD) System'' and revise TS 3.6.3.1, ``Drywell 
Cooling System Fans,'' and the associated Bases, to modify containment 
combustible gas control requirements as permitted by 10 CFR 50.44. This 
change is consistent with NRC approved Revision 2 to Technical 
Specification Task Force (TSTF) Improved Standard Technical 
Specification Change Traveler, TSTF-478, ``BWR Technical Specification 
Changes that Implement the Revised Rule for Combustible Gas Control.'' 
[Discuss any differences with TSTF-478, Revision 2.] The availability 
of this TS improvement was announced in the Federal Register on [Date] 
([ ] FR [ ]) as part of the consolidated line item improvement process 
(CLIIP).
    Attachment 1 provides an evaluation of the proposed change. 
Attachment 2 provides the existing TS pages marked up to show the 
proposed change. Attachment 3 provides the proposed TS changes in final 
typed format. Attachment 4 provides the existing Bases pages marked up 
to show the proposed change.
    [LICENSEE] requests approval of the proposed license amendment by 
[DATE], with the amendment being implemented [BY DATE OR WITHIN X 
DAYS].
    In accordance with 10 CFR 50.91, a copy of this application, with 
attachments, is being provided to the designated [STATE] Official.
    If you should have any questions regarding this submittal, please 
contact [ ].
    I declare [or certify, verify, state] under penalty of perjury that 
the foregoing is true and correct. [NAME, TITLE]
    Attachments:
    1. Evaluation of Proposed Change
    2. Proposed Technical Specification Change (Mark-Up)
    3. Proposed Technical Specification Change (Re-Typed)
    4. Proposed Technical Specification Bases Change (Mark-Up)

cc: [NRR Project Manager]
[Regional Office]
[Resident Inspector]
[State Contact]

Attachment 1--Evaluation of Proposed Change

    License Amendment Request for Adoption of TSTF-478, Rev. 2, ``BWR 
Technical Specification Changes that Implement the Revised Rule for 
Combustible Gas Control''

1.0 Description
2.0 Proposed Change
3.0 Background
4.0 Technical Analysis
5.0 Regulatory Safety Analysis
    5.1 No Significant Hazards Determination
    5.2 Applicable Regulatory Requirements/Criteria
6.0 Environmental Consideration
7.0 References

1.0 Description

    The proposed amendment would delete TS 3.6.3.3, ``Containment 
Atmosphere Dilution (CAD) System'' and revise TS 3.6.3.1, ``Drywell 
Cooling System Fans,'' and the associated Bases, that will result in 
modifications to containment combustible gas control TS requirements as 
permitted by 10 CFR 50.44. This change is consistent with NRC approved 
Revision 2 to Technical Specification Task Force (TSTF) Improved 
Standard Technical Specification Change Traveler, TSTF-478, ``BWR 
Technical Specification Changes that Implement the Revised Rule for 
Combustible Gas Control.'' The availability of this TS improvement was 
announced in the Federal Register on [Date] ([ ] FR [ ]) as part of the 
consolidated line item improvement process (CLIIP).

2.0 Proposed Change

    Consistent with the NRC approved Revision 2 of TSTF-478, the 
proposed TS changes delete TS 3.6.3.3, ``Containment Atmosphere 
Dilution (CAD) System'' and revise TS 3.6.3.1, ``Drywell Cooling System 
Fans.'' Proposed revisions to the TS Bases are also included in this 
application. Adoption of the TS Bases associated with TSTF-478, 
Revision 2 is an integral part of implementing this TS amendment. The 
changes to the affected TS Bases pages will be incorporated in 
accordance with the TS Bases Control Program.
    This application is being made in accordance with the CLIIP. 
[LICENSEE] is [not] proposing variations or deviations from the TS 
changes described in TSTF-478, Revision 2, or the NRC staff's model 
safety evaluation (SE) published on [DATE] ([ ] FR [ ]) as part of the 
CLIIP Notice of Availability. [Discuss any differences with TSTF-478, 
Revision 2.]

3.0 Background

    The background for this application is adequately addressed by the 
NRC Notice of Availability published on [DATE] ([ ] FR [ ]).

4.0 Technical Analysis

    [LICENSEE] has reviewed the safety evaluation (SE) published on 
[DATE] ([ ] FR [ ]) as part of the CLIIP Notice of Availability. 
[LICENSEE] has concluded that the technical justifications presented in 
the SE prepared by the NRC staff are applicable to [PLANT, UNIT NO.] 
and therefore justify this amendment for the incorporation of the 
proposed changes to the [PLANT] TS.

5.0 Regulatory Safety Analysis

5.1 No Significant Hazards Determination

    [LICENSEE] has reviewed the no significant hazards determination 
published on [DATE] ([ ] FR [ ]) as part of the CLIIP Notice of 
Availability. [LICENSEE] has concluded that the determination presented 
in the notice is applicable to [PLANT, UNIT NO.] and the determination 
is hereby incorporated by reference to satisfy the requirements of 10 
CFR 50.91(a).

5.2 Applicable Regulatory Requirements/Criteria

    A description of the proposed TS change and its relationship to 
applicable regulatory requirements was provided in the NRC Notice of 
Availability published on [DATE] ([ ] FR [ ]).

6.0 Environmental Consideration

    [LICENSEE] has reviewed the environmental evaluation included in 
the safety evaluation (SE) published on [DATE] ([ ] FR [ ]) as part of 
the CLIIP Notice of Availability. [LICENSEE] has concluded that the 
staff's findings presented in that evaluation are applicable to [PLANT, 
NO.] and the evaluation is hereby incorporated by reference for this 
application.

7.0 References

    1. Federal Register Notice, Notice of Availability published on 
[DATE] ([ ] FR [ ]).
    2. TSTF-478 Revision 2, ``BWR Technical Specification Changes that 
Implement the Revised Rule for Combustible Gas Control.''

Attachment 2--Proposed Technical Specification Change (Mark-Up)

Attachment 3--Proposed Technical Specification Change (Re-Typed)

Attachment 4--Proposed Technical Specification Bases Change (Mark-Up)

    Model Safety Evaluation
    U.S. Nuclear Regulatory Commission, Office of Nuclear Reactor 
Regulation, Consolidated Line Item Improvement.
    Technical Specification Task Force Change TSTF-478, Revision 2, 
``BWR Technical Specification Changes that Implement the Revised Rule 
for Combustible Gas Control''

[[Page 65613]]

1.0 Introduction

    By application dated [Date], [Name of Licensee] (the licensee) 
requested changes to the Technical Specifications (TS) for the [Name of 
Facility].
    The proposed changes would:
    1. Delete TS 3.6.3.3, ``Containment Atmosphere Dilution (CAD) 
System''
    2. Revise TS 3.6.3.1, ``Drywell Cooling System Fans'' eliminate 
Required Action B.1. Required Action B.1 requires operators to verify 
by administrative means that a hydrogen control function is maintained 
in the primary containment when two required drywell cooling system 
fans are inoperable.
    The licensee stated that the application is consistent with NRC 
approved Revision 2 to Technical Specification Task Force (TSTF) 
Improved Standard Technical Specification Change Traveler, TSTF-478, 
``BWR Technical Specification Changes that Implement the Revised Rule 
for Combustible Gas Control.'' [Discuss any differences with TSTF-478, 
Revision 2.] The availability of this TS improvement was announced in 
the Federal Register on [Date] ([ ] FR [ ]) as part of the consolidated 
line item improvement process (CLIIP).

2.0 Regulatory Evaluation

    General Design Criterion (GDC) 41, ``Containment atmosphere 
cleanup,'' of Appendix A to 10 CFR part 50 requires, in part, that 
systems to control fission products, hydrogen, oxygen, and other 
substances that may be released into the reactor containment shall be 
provided as necessary to reduce the concentration and quality of 
fission products and control the concentration of hydrogen, oxygen, and 
other substances in the containment atmosphere following postulated 
accidents to assure that containment integrity is maintained. Section 
50.44, ``Combustible Gas Control for Nuclear Power Reactors,'' of Title 
10 of the Code of Federal Regulations (10 CFR) provides, among other 
things, standards for controlling combustible gas that may accumulate 
in the containment atmosphere during accidents.
    10 CFR 50.44 was revised on September 16, 2003 (68 FR 54123), as a 
result of studies that led to an improved understanding of combustible 
gas behavior during severe accidents. The studies confirmed that the 
hydrogen release postulated from a design-basis Loss of Coolant 
Accident (LOCA) was not risk significant because it was not large 
enough to lead to early containment failure, and that the risk 
associated with hydrogen combustion was from beyond design-basis (i.e., 
severe) accidents. As a result, requirements for maintaining hydrogen 
control equipment associated with a design-basis LOCA were eliminated 
from 10 CFR 50.44. Regulatory Guide (RG) 1.7, ``Control of Combustible 
Gas Concentrations in Containment Following a Loss-of-Coolant 
Accident,'' Revision 3, dated March 2007, provides detailed guidance 
that would be acceptable for implementing 10 CFR 50.44.
    Section 182a of the Atomic Energy Act requires applicants for 
nuclear power plant operating licenses to include TS as part of the 
license application. The TS, among other things, help to ensure the 
operational capability of structures, systems, and components that are 
required to protect the health and safety of the public. The NRC's 
regulatory requirements related to the content of the TS are contained 
in Section 50.36 of Title 10 of the Code of Federal Regulations (10 CFR 
50.36), which requires that the TS include items in the following 
categories: (1) Safety limits, limiting safety systems settings, and 
limiting control settings; (2) limiting conditions for operation 
(LCOs); (3) Surveillance Requirements (SR); (4) design features; and 
(5) administrative controls. 10 CFR 50.36(c)(2)(i) states, in part, 
that ``limiting conditions for operation are the lowest functional 
capability or performance levels of equipment required for safe 
operation of the facility. When a limiting condition for operation of a 
nuclear reactor is not met, the licensee shall shut down the reactor or 
follow any remedial action permitted by the technical specifications 
until the condition can be met.'' TSTF-478, Revision 2 contains changes 
to remedial actions permitted by the technical specifications.

2.1 Containment Atmosphere Dilution System

    The design purpose of the CAD system is to maintain combustible gas 
concentrations within the primary containment at or below the 
flammability limits following a postulated LOCA by diluting hydrogen 
and oxygen with the addition of nitrogen. The CAD system, however, is 
considered ineffective at mitigating hydrogen releases from the more 
risk significant beyond design-basis accidents that could threaten 
primary containment integrity. The revised 10 CFR 50.44 rule requires 
systems and measures be in place to reduce the risks associated with 
combustible gases from beyond design-basis accidents and eliminates 
requirements for maintaining hydrogen and oxygen control equipment 
associated with a design-basis LOCA. As a result, the CAD system is no 
longer a mitigating safety system required to be maintained per the 
revised 10 CFR 50.44 rule. TS 3.6.3.3, ``Containment Atmosphere 
Dilution (CAD) System,'' can therefore be deleted, and the technical 
basis for allowing the deletion is found in Section 3.0, Technical 
Evaluation.

2.2 Drywell Cooling System Fans

    10 CFR 50.44 requires that all primary containments must have a 
capability for ensuring a mixed atmosphere. The purpose of the Drywell 
Cooling System Fans is to ensure a uniformly mixed post accident 
primary containment atmosphere. Drywell Cooling System Fans are a 
mitigating safety system that meets the requirements of 10 CFR 50.44. 
The proposed TS change modifies the Required Actions that operators 
must take when the Drywell Cooling System Fans are inoperable in 
accordance with 10 CFR 50.36(c)(2)(i). Therefore, the Remedial Actions 
and associated allowed Completion Times when Drywell Cooling System 
Fans are inoperable may be revised as permitted by 10 CFR 
50.36(c)(2)(i). The technical basis for allowing the revision to the 
Required Actions in STS 3.6.3.1, ``Drywell Cooling System Fans,'' is 
found in Section 3.0, Technical Evaluation.

3.0 Technical Evaluation

3.1 Containment Atmosphere Dilution System

    BWRs with Mark I containment designs have either installed hydrogen 
recombiners or CAD systems to meet requirements for combustible gas 
control following a design-basis LOCA. The hydrogen recombiners and the 
CAD system perform similar functions for post-LOCA gas control by 
decreasing the hydrogen concentration. Hydrogen recombiners function to 
reduce the combustible gas concentration in the primary containment by 
recombining hydrogen and oxygen to form water vapor. The CAD system 
functions to maintain combustible gas concentrations within the primary 
containment at or below the flammability limits following a postulated 
LOCA by diluting hydrogen and oxygen by adding nitrogen to the mixture.
    Studies performed in support of the 10 CFR 50.44 rule change 
(September 16, 2003, 68 FR 54123) confirmed that the hydrogen release 
postulated from a design-basis LOCA was not risk significant because it 
was not large

[[Page 65614]]

enough to lead to early containment failure, and that the risk 
associated with hydrogen combustion was from beyond design-basis (i.e., 
severe) accidents. As a result, the revised 10 CFR 50.44 rule 
eliminates requirements for maintaining hydrogen control equipment 
associated with a design-basis LOCA and requires systems and measures 
be in place to reduce the risks associated with hydrogen combustion 
from beyond design-basis accidents.
    The CAD system maintains combustible gas concentrations within the 
primary containment at or below the flammability limits following a 
LOCA, however, this system, as discussed in the 10 CFR 50.44 rule 
change was shown to be ineffective at mitigating hydrogen releases from 
the more risk significant beyond design-basis accidents that could 
threaten primary containment integrity, and is no longer required to 
address a design-basis LOCA. Therefore, the staff finds that the 
deletion of TS 3.6.3.3, ``Containment Atmosphere Dilution (CAD) 
System,'' is acceptable.

3.2 Drywell Cooling System Fans

    The design function of the Drywell Cooling System Fans is to ensure 
a uniformly mixed post accident primary containment atmosphere. LCO 
3.6.3.1 requires that two Drywell Cooling System Fans shall be 
operable. One Drywell Cooling System Fan, and associated subsystem 
components, is needed to perform the mitigating system safety function. 
When both required Drywell Cooling System Fans are inoperable, Required 
Action B.1 requires operators to verify by administrative means that a 
hydrogen control function is maintained in the primary containment, and 
Required Action B.2 requires operators to restore one required Drywell 
Cooling System Fan to operable status. The Completion Time for Required 
Action B.1 is within 1 hour and once per 12 hours thereafter, while the 
Completion Time for Required Action B.2 is within 7 days. The license 
amendment request proposes to eliminate Required Action B.1. As a 
result of the proposed revision, operators would only be required to 
restore one required Drywell Cooling System Fan to operable status 
within 7 days when two required Drywell Cooling System Fans are 
inoperable.
    The NRC staff considered the consequences of having two required 
Drywell Cooling System Fans inoperable for 7 days without operators 
having to verify by administrative means that a hydrogen control 
function is maintained in the primary containment. Neither NUREG-1150, 
``Severe Accident Risks: An Assessment for Five U.S. Nuclear Power 
Plants,'' nor the technical analyses in support of the risk-informed 
changes to 10 CFR 50.44, credit the function of the drywell fans in a 
beyond design-basis (i.e., severe) accident because the fans are deemed 
ineffective in preventing a challenge to containment integrity due to 
combustible gas accumulation in a deinerted containment. Because Mark I 
and II containments are inerted, the risk significance of keeping the 
atmosphere mixed to prevent hydrogen combustion is low. Based on the 
above discussion, and the limited time (7 days) that the Drywell 
Cooling System Fans would be unavailable, the NRC staff finds that the 
proposed revision to TS 3.6.3.1, ``Drywell Cooling System Fans,'' is 
acceptable.

4.0 State Consultation

    In accordance with the Commission's regulations, the [Name of 
State] State official was notified of the proposed issuance of the 
amendment. The State official had [no] comments. [If comments were 
provided, they should be addressed here].

5.0 Environmental Consideration

    The amendment changes a requirement with respect to installation or 
use of a facility component located within the restricted area as 
defined in 10 CFR Part 20. The NRC staff has determined that the 
amendment involves no significant increase in the amounts, and no 
significant change in the types, of any effluents that may be released 
offsite, and that there is no significant increase in individual or 
cumulative occupational radiation exposure. The Commission has 
previously issued a proposed finding that the amendment involves no 
significant hazards consideration, and there has been no public comment 
on such finding issued on [Date] ([ ] FR [ ]). Accordingly, the 
amendment meets the eligibility criteria for categorical exclusion set 
forth in 10 CFR 51.22(c)(9). Pursuant to 10 CFR 51.22(b) no 
environmental impact statement or environmental assessment needs to be 
prepared in connection with the issuance of the amendment.

6.0 Conclusion

    The Commission has concluded, based on the considerations discussed 
above, that: (1) There is reasonable assurance that the health and 
safety of the public will not be endangered by operation in the 
proposed manner, (2) such activities will be conducted in compliance 
with the Commission's regulations, and (3) the issuance of the 
amendment will not be inimical to the common defense and security or to 
the health and safety of the public.

7.0 References

    3. Federal Register Notice, Notice of Availability published on 
[DATE] ([ ] FR [ ]).
    4. TSTF-478 Revision 2, ``BWR Technical Specification Changes that 
Implement the Revised Rule for Combustible Gas Control.''
    Principal Contributors: [Brian Lee, Aron Lewin, Robert Palla]

Model No Significant Hazards Determination

    Description of Amendment Request: The proposed amendment would 
delete TS 3.6.3.3, ``Containment Atmosphere Dilution (CAD) System'' and 
revise TS 3.6.3.1, ``Drywell Cooling System Fans,'' and the associated 
Bases, that will result in modifications to technical specification 
(TS) containment combustible gas control requirements as permitted by 
10 CFR 50.44.
    Basis for No Significant Hazards Determination: As required by 10 
CFR 50.91(a), an analysis of the issue of no significant hazards 
consideration is presented below:
    Criterion 1: The proposed change does not involve a significant 
increase in the probability or consequences of an accident previously 
evaluated.
    The Containment Atmosphere Dilution (CAD) system is not an 
initiator to any accident previously evaluated. The TS Required Actions 
taken when a drywell cooling system fan is inoperable are not 
initiators to any accident previously evaluated. As a result, the 
probability of any accident previously evaluated is not significantly 
increased.
    The revised 10 CFR 50.44 no longer defines a design basis accident 
(DBA) hydrogen release and the Commission has subsequently found that 
the DBA loss of coolant accident (LOCA) hydrogen release is not risk 
significant. In addition, CAD has been determined to be ineffective at 
mitigating hydrogen releases from the more risk significant beyond 
design basis accidents that could threaten containment integrity. 
Therefore, elimination of the CAD system will not significantly 
increase the consequences of any accident previously evaluated. The 
consequences of an accident while relying on the revised TS Required 
Actions for drywell cooling system fans are no different than the 
consequences of the same accidents under the current Required Actions. 
As a result, the consequences of any accident previously evaluated is 
not significantly increased.

[[Page 65615]]

    Therefore, the proposed change does not involve a significant 
increase in the probability or consequences of an accident previously 
evaluated.
    Criterion 2: The proposed change does not create the possibility of 
a new or different kind of accident from any accident previously 
evaluated.
    No new or different accidents result from utilizing the proposed 
change. The proposed change permits physical alteration of the plant 
involving removal of the CAD system. The CAD system is not an accident 
precursor, nor does its existence or elimination have any adverse 
impact on the pre-accident state of the reactor core or post accident 
confinement of radionuclides within the containment building from any 
design basis event. The changes to the TS do not alter assumptions made 
in the safety analysis, but reflect changes to the design requirements 
allowed under the revised 10 CFR 50.44. The proposed change is 
consistent with the revised safety analysis assumptions.
    Therefore, the proposed change does not create the possibility of a 
new or different kind of accident from any previously evaluated.
    Criterion 3: The proposed change does not involve a significant 
reduction in a margin of safety.
    The Commission has determined that the DBA LOCA hydrogen release is 
not risk significant, therefore is not required to be analyzed in a 
facility accident analysis. The proposed change reflects this new 
position and, due to remaining plant equipment, instrumentation, 
procedures, and programs that provide effective mitigation of and 
recovery from reactor accidents, including postulated beyond design 
basis events, does not result in a significant reduction in a margin of 
safety.
    Therefore, the proposed change does not involve a significant 
reduction in a margin of safety.
    Based on the above, the NRC concludes that the proposed change 
presents no significant hazards consideration under the standards set 
forth in 10 CFR 50.92(c), and, accordingly, a finding of ``no 
significant hazards consideration'' is justified.

 [FR Doc. E7-22740 Filed 11-20-07; 8:45 am]
BILLING CODE 7590-01-P