E7-20084. 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 ...

AGENCY:

Nuclear Regulatory Commission.

ACTION:

Request for comment.

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 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 [e-mail].

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 [phone].

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 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”

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” 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 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.

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.