ML20191A231
| ML20191A231 | |
| Person / Time | |
|---|---|
| Site: | Nuclear Energy Institute |
| Issue date: | 01/04/2021 |
| From: | Anderson V, Powell M Nuclear Energy Institute, PWR Owners Group |
| To: | Office of Nuclear Regulatory Research |
| Gardocki S | |
| Shared Package | |
| ML20164A029 | List: |
| References | |
| DG-1287, RG-1.177, Rev 2 | |
| Download: ML20191A231 (6) | |
Text
Response to Public Comments on Draft Regulatory Guide DG-1287, Plant-Specific, Risk-Informed Decisionmaking: Technical Specifications, Proposed Revision 2 to Regulatory Guide 1.177 On February 19, 2020, the U.S. Nuclear Regulatory Commission (NRC) published a notice in Volume 85 of the Federal Register, page 9498 (85 FR 9498),
announcing the availability of Draft Regulatory Guide (DG) 1287 (proposed Revision 2 of Regulatory Guide (RG) 1.177) for public comment. The public comment period ended on April 20, 2020. The NRC received comments from the individuals and organizations listed below. The bracketed identifiers at the end of each comment relate to the annotations that the NRC applied to the received comment documents. Annotated versions of the comment documents received are available in the Agencywide Documents Access and Management System (ADAMS) under the indicated accession numbers. The table following the list of commenters shows the public comments and NRC staffs responses.
The NRC received comments from the following:
Ms. Victoria K. Anderson < vka@nei.org >
Nuclear Energy Institute 1291 F Street, NW, Suite 1100 Washington, DC 20004 Dated: April 16, 2020 ADAMS Accession No.: ML20212L864 Mr. Michael Powell PWR Owners Group Program Management Office 1000 Westinghouse Drive Cranberry Township, Pennsylvania 16066 Dated: April 15, 2020 ADAMS Accession No.: ML20212L866 Commenter Comment Category Specific Comments NRC Resolution Ms. Victoria K.
Anderson Content of the Guidance The ICCDP/ICLERP limits in Section 2.4 are inconsistent with those given in NEI 06-09, Risk-Informed Technical Specifications Initiative 4b: Risk-Managed Technical Specifications (RMTS)
Guidance. To avoid confusion over which document has precedence for future applications, a footnote should be added to identify this exception for plants that adopt the provisions of NEI 06-09. [NEI1-1]
The NRC staff notes the comment but did not change the regulatory guide in response to this comment.
DG-1287 (RG 1.177) assesses the impact on plant risk as expressed by the change in core damage frequency and change in large early release frequency. It also evaluates plant risk while equipment covered by the proposed completion time (CT) is out of service, as represented by incremental conditional core damage probability (ICCDP) and incremental conditional large early release probability (ICLERP). The limits for ICCDP and ICLERP are
2 Commenter Comment Category Specific Comments NRC Resolution consistent with the criteria for incremental core damage probability (ICDP) and incremental large early release probability (ILERP) from the guidance in Nuclear Management and Resources Council (NUMARC) 93-01, Revision 4F, Industry Guideline for Monitoring the Effectiveness of Maintenance at Nuclear Power Plants, issued April 2018 (ADAMS Accession No. ML18120A069), for managing the risk of online maintenance activities. The NRC staff endorsed this guidance, with certain provisions and clarifications, in RG 1.160, Revision 4, Monitoring the Effectiveness of Maintenance at Nuclear Power Plants, issued August 2018 (ADAMS Accession No. ML18220B281), as an acceptable approach for compliance with the Maintenance Rule in Title 10 of the Code of Federal Regulations (10 CFR) 50.65(a)(4). The ICDP and ILERP are the limits on which licensees base the risk-informed completion times under Nuclear Energy Institute (NEI) Topical Report 06-09, Revision 0-A, Risk-Informed Technical Specifications Initiative 4b, Risk-Managed Technical Specifications (RMTS) Guidelines, issued November 2006 (ADAMS Accession No. ML12286A322). As a result, the NRC staff concludes that no change to the RG is warranted.
Ms. Victoria K.
Anderson Revised Structure or Framework The discussion of Maintenance Rule Performance Criteria in Section 3.2 should be revised to include Performance Monitoring to address plants that have transitioned to Maintenance Rule 2.0, which does not involve the use of Performance Criteria. [NEI1-2]
The NRC staff notes the comment but did not change the RG in response to this comment.
Section A of DG-1287 (RG 1.177) states the following:
The NRC issues regulatory guides to describe to the public methods that the staff considers acceptable for use in implementing specific parts of the agencys regulations, to explain techniques that
3 Commenter Comment Category Specific Comments NRC Resolution the staff uses in evaluating specific problems or postulated accidents, and to provide guidance to applicants.
The NRC staff has found acceptable the approach for compliance with 10 CFR 50.65, Requirements for monitoring the effectiveness of maintenance at nuclear power plants, described in NUMARC 93-01, Revision 4F, as endorsed with certain provisions and clarifications by RG 1.160, Revision 4. The industry has not requested, and the NRC staff has not endorsed, the Maintenance Rule 2.0 approach and associated industry guidance described in NEI 18-10, Revision 0, Monitoring the Effectiveness of Nuclear Power Plant Maintenance, issued July 2019 (ADAMS Accession No. ML19302F210). Therefore, Maintenance Rule 2.0 does not represent an NRC-endorsed approach for compliance with 10 CFR 50.65; the revised RG 1.177 likewise makes no such endorsement, and licensees should not infer any such endorsement.
Ms. Victoria K.
Anderson.
Content of the Guidance Section 2.2.2, paragraph (a) states that sufficient safety margins are maintained if Codes and standards (e.g., American Society of Mechanical Engineers, Institute of Electrical and Electronics Engineers) or alternatives approved for use by the NRC are met (e.g., the proposed TS CT or SF change does not conflict with approved codes and standards relevant to the subject system).
However, licensees may also extend surveillances or outage times if a relief request is granted under a specific code or standard. This paragraph should be clarified to include relief requests, such as those The NRC staff notes the comment but did not change the RG in response to this comment.
Licensees may extend surveillances or outage times if a relief request is granted or for other reasons addressed in other license terms. This should already be part of a relief request application when a CT or SF change is in place for an amendment request using the approach in this RG, and they are included in alternatives approve for use by the NRC as appropriate. Therefore, no revision to the RG is warranted.
4 Commenter Comment Category Specific Comments NRC Resolution related to diesel generator testing for insurance standard purposes, as well. [NEI1-3]
Mr. Michael Powell Content of the Guidance Page 21 & 22 - The ICCDP/ICLERP limits are inconsistent/lower than those allowed in NEI 06-09.
To avoid confusion over which document has precedence for future applications, a footnote should be added to identify this exception.
[PWROG2-1]
The NRC staff notes the comment but did not change the RG.
This comment is similar to comment [NEI1-1]. The NRC disagrees with this comment; no change is needed for the same reasons noted in the NRCs response to NEI 1-1.
Mr. Michael Powell Content of the Guidance Page 23 Section 2.6 Integrated Decision Making.
This section notes that TS changes should not be based solely on the results of numerical PRA results.
And equivalent discussion on not basing changes solely on deterministic results should be added to ensure decision reflect an Integrated Risk Informed process. [PWROG2-2]
The NRC staff notes the comment but did not change the RG in response to this comment.
DG-1287 (RG 1.177) specifically provides guidance on acceptable methods for using probabilistic risk assessment (PRA) information with established deterministic (traditional) engineering information in the development of risk-informed decisionmaking for technical specification changes. In the NRC policy statement on the use of PRA methods in nuclear regulatory activities, the Commission stated its expectation that the use of PRA technology should be increased in all regulatory mattersin a manner that complements the NRCs deterministic approach and supports the NRCs traditional defense-in-depth philosophy. (Federal Register, Vol. 60, No. 158, August 16, 1995, pp. 42622-42629)
Section C.2.6 of RG 1.174, An Approach for Using Probabilistic Risk Assessment in Risk-Informed Decisions on Plant-Specific Changes to the Licensing Basis, has adequately addressed the relative weight given to the risk assessment element of the decisionmaking process, including the deterministic (traditional) engineering approach.
5 Commenter Comment Category Specific Comments NRC Resolution Licensees may still use deterministic (traditional) engineering approaches alone. However, as explained in DG-1287, For TS change requests that go beyond current staff positionsthe staff will review the information providedand will either approve or reject the application based upon the review.
Based upon the discussion above, no revision to the RG is warranted in response to this comment.
Mr. Michael Powell Revised Structure or Framework Page 23 Section 3.2 - The discussion of Maintenance Rule Performance Criteria should be revised to Performance Monitoring to address plants that have transitioned to Maintenance Rule 2.0 where performance criteria arent used. [PWROG2-3]
The NRC staff notes the comment but did not change the RG in response to this comment.
This comment is similar to comment [NEI1-2]. The NRC staff disagrees with this comment; no change is needed for the same reasons stated in the NRCs response to NEI 1-2.
Mr. Michael Powell Content of the Guidance Page A-3 Section A-1.3.1 - Setting an event to True in a PRA model can have different impacts depending on the software used. It would be beneficial to define what is meant. [PWROG2-4]
The NRC staff notes the comment but did not change the RG in response to this comment.
The intent of Section A-1.3.1 of DG-1287 (RG 1.177) is to discuss alternative ways of calculating the risk measures for technical specification changes. This section does not intend to address the idiosyncrasies of various PRA software programs used to quantify the PRA, which are beyond the scope of this RG. As a result, the NRC staff does not believe a change to the RG is warranted.
Mr. Michael Powell Content of the Guidance The purpose should note risk informed Technical Specification changes are one option, and that other options, such a deterministically based changes are allowed but not covered by this Regulatory Guide.
[PWROG2-5]
The NRC staff notes the comment but did not change the RG in response to this comment.
The Background section in Part B of RG 1.177 notes:
6 Commenter Comment Category Specific Comments NRC Resolution The staff normally uses deterministic engineering analysis to evaluate license amendment requests for TS changes that are consistent with approved staff positions (e.g., generic letters, regulatory guides, standard review plans, branch technical positions, or the Standard Technical Specifications (STS) (Refs. 10-14)). For TS change requests that go beyond current staff positions, in which a licensee elects to use risk information in support of the proposed TS change, the staffs evaluation may use deterministic engineering analyses and the risk-informed approach set forth in this RG. The staff will review the information provided by the licensee to determine whether it can approve the application based on the information provided using deterministic and risk-informed methods, as applicable, and will either approve or reject the application based upon the review.
The guidance provided within this guide does not preclude other approaches for requesting changes to the TS. Rather, this RG is intended to improve consistency in regulatory decisions when the results of risk analyses are used to help justify TS changes.
In addition, see the staffs comment on [PWROG2-2].
Based upon the above, the staff finds that no change to the RG is warranted.