[Federal Register Volume 72, Number 196 (Thursday, October 11, 2007)]
[Notices]
[Pages 57970-57975]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E7-20084]
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NUCLEAR REGULATORY COMMISSION
Notice of Opportunity To Comment 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: Request for comment.
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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 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. The NRC
staff is requesting comment on the model SE, model application, and
model NSHC determination prior to announcing their availability for
referencing in license amendment applications.
DATES: The comment period expires November 13, 2007. Comments received
after this date will be considered if it is practical to do so, but the
Commission is able to ensure consideration only of comments received on
or before this date.
ADDRESSES: Comments may be submitted either electronically or via U.S.
mail. Submit written comments to Chief, Rulemaking, Directives and
Editing Branch, Division of
[[Page 57971]]
Administrative Services, Office of Administration, Mail Stop: T-6 D59,
U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001. Hand
deliver comments to: 11545 Rockville Pike, Rockville, Maryland, between
7:45 a.m. and 4:15 p.m. on Federal workdays. Copies of comments
received may be examined at the NRC's Public Document Room, 11555
Rockville Pike (Room O-1F21), Rockville, Maryland. Comments may be
submitted by electronic mail to [email protected].
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. This notice solicits comment on a proposal to delete STS
3.6.3.3, ``Containment Atmosphere Dilution (CAD) System'' and modify
STS 3.6.3.1, ``Drywell Cooling System Fans,'' in NUREG-1433 to
establish TS for containment combustible gas control requirements in
accordance with 10 CFR 50.44. 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
This notice requests comments from interested members of the public
within 30 days of the date of publication in the Federal Register.
After evaluating the comments received as a result of this notice, the
staff will either reconsider the proposed change or announce the
availability of the change in a subsequent notice (perhaps with some
changes to the safety evaluation or the proposed no significant hazards
consideration determination as a result of public comments). If the
staff announces the availability of the change, 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 3rd of October 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
Atmosphere Dilution (CAD) System'' and revise TS 3.6.3.1, ``Drywell
Cooling System Fans,'' and the associated Bases, to modify
containment
[[Page 57972]]
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]----------------------------------------------------------
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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''
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:
[[Page 57973]]
1. Delete TS 3.6.3.3, ``Containment Atmosphere Dilution (CAD)
System.''
2. Revise TS 3.6.3.1, ``Drywell Cooling System Fans'' to 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.
Section 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
Section 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 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
[[Page 57974]]
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.
Therefore, the proposed change does not involve a significant
increase in the probability or consequences of an accident previously
evaluated.
[[Page 57975]]
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. E7-20084 Filed 10-10-07; 8:45 am]
BILLING CODE 7590-01-P