2020-28632. Acceptability of Probabilistic Risk Assessment Results for Risk-Informed Activities  

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    AGENCY:

    Nuclear Regulatory Commission.

    ACTION:

    Regulatory guide; issuance.

    SUMMARY:

    The U.S. Nuclear Regulatory Commission (NRC) is issuing Revision 3 to Regulatory Guide (RG) 1.200, “Acceptability of Probabilistic Risk Assessment Results for Risk-Informed Activities.” Revision 3 describes one acceptable approach for determining whether a base probabilistic risk assessment (PRA), in total or the portions that are used to support an application, is acceptable to provide confidence in the results, such that the PRA can be used in regulatory decisionmaking for light-water reactors (LWRs). When used in support of an application, the use of this RG will obviate the need for an in-depth review of the base PRA by NRC reviewers, allowing them to focus their review on key assumptions and areas identified by peer reviewers.

    DATES:

    Revision 3 to RG 1.200 is available on December 29, 2020.

    ADDRESSES:

    Please refer to Docket ID NRC-2012-0110 when contacting the NRC about the availability of information regarding this document. You may obtain publicly available information related to this document using any of the following methods:

    • Federal Rulemaking Website: Go to https://www.regulations.gov and search for Docket ID NRC-2012-0110. Address questions about Docket IDs in Regulations.gov to Jennifer Borges; telephone: 301-287-9127; email: Jennifer.Borges@nrc.gov. For technical questions, contact the individuals listed in the FOR FURTHER INFORMATION CONTACT section of this document.
    • NRC's Agencywide Documents Access and Management System (ADAMS): You may obtain publicly available documents online in the ADAMS Public Documents collection at https://www.nrc.gov/​reading-rm/​adams.html. To begin the search, select “Begin Web-based ADAMS Search.” For problems with ADAMS, please contact the NRC's Public Document Room (PDR) reference staff at 1-800-397-4209, 301-415-4737, or by email to pdr.resource@nrc.gov. The ADAMS accession number for each document referenced (if it is available in ADAMS) is provided the first time that it is mentioned in this document.
    • Attention: The PDR, where you may examine and order copies of public documents is currently closed. You may submit your request to the PDR via email at pdr.resource@nrc.gov or call 1-800-397-4209 between 8:00 a.m. and 4:00 p.m. (EST), Monday through Friday, except Federal holidays.

    Regulatory guides are not copyrighted, and NRC approval is not required to reproduce them.

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    FOR FURTHER INFORMATION CONTACT:

    Anders Gilbertson, telephone: 301-415-1541, email: Anders.Gilbertson@nrc.gov, and Harriet Karagiannis, telephone: 301-415-2493, email: Harriet.Karagiannis@nrc.gov. Both are staff of the Office of Nuclear Regulatory Research, U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001.

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    SUPPLEMENTARY INFORMATION:

    I. Discussion

    The NRC is issuing a revision to an existing guide in the NRC's “Regulatory Guide” series. This series was developed to describe and make available to the public information regarding methods that are acceptable to the NRC staff for implementing specific parts of the agency's regulations, techniques that the NRC staff uses in evaluating specific issues or postulated events, and data that the NRC staff needs in its review of applications for permits and licenses. Regulatory guides are not NRC regulations and compliance with them is not required. Methods and solutions that differ from those set forth in RGs are acceptable if supported by a basis for the issuance or continuance of a permit or license by the Commission.

    Revision 3 to RG 1.200 was issued with a temporary identification of Draft Regulatory Guide, DG-1362 (ADAMS Accession No. ML19308B636). RG 1.200 (Revision 3) describes one acceptable approach for determining whether the base PRA, in total or the portions that are used to support an application, is Start Printed Page 85683sufficient to provide confidence in the results, such that the PRA can be used in regulatory decisionmaking for LWRs. Also, it addresses new industry guidance and enhancements identified since the last revision was issued in March 2009. Specifically, this revision endorses, with staff clarifications and exceptions, the American Society of Mechanical Engineers (ASME) and American Nuclear Society (ANS) Standard ASME/ANS RA-Sa-2009, “Standard for Level 1/Large Early Release Frequency Probabilistic Risk Assessment for Nuclear Power Plant Applications”; the ASME/ANS standard ASME/ANS RA-S Case 1 for seismic PRA, “Case for ASME/ANS RA-Sb-2013 Standard for Level 1/Large Early Release Frequency Probabilistic Risk Assessment of Nuclear Power Plant Applications”; Nuclear Energy Institute (NEI) 17-07, Revision 2, “Performance of PRA Peer Reviews Using the ASME/ANS PRA Standard” (ADAMS Accession No. ML19241A615); and Pressurized Water Reactor Owners Group (PWROG) report PWROG-19027-NP, Revision 2, “Newly Developed Method Requirements and Peer Review” (ADAMS Accession No. ML20213C660). This revision of the RG further provides for a peer review of newly developed methods, clarifies the process for determining how to classify changes to a PRA, provides definitions related to newly developed methods and other PRA terms, and enhances guidance related to key assumptions and sources of uncertainty.

    II. Additional Information

    The NRC published a notice of the availability of DG-1362 in the Federal Register on July 1, 2020 (85 FR 39599) for a 30-day public comment period. The public comment period closed on July 31, 2020. Public comments on DG-1362 and the staff responses to the public comments are available in ADAMS under Accession No. ML20238B873. Revision 3 to RG 1.200 may be found in ADAMS under Accession No. ML20238B871.

    III. Congressional Review Act

    This RG is a rule as defined in the Congressional Review Act (5 U.S.C. 801-808). However, the Office of Management and Budget has not found it to be a major rule as defined in the Congressional Review Act.

    IV. Backfitting, Forward Fitting, and Issue Finality

    This RG provides one acceptable approach for determining whether the base PRA, in total or the portions that are used to support an application, is sufficient to provide confidence in the results, such that the PRA can be used in regulatory decisionmaking for LWRs. Issuance of this RG does not constitute backfitting as defined in section 50.109 of title 10 of the Code of Federal Regulations (10 CFR), “Backfitting,” and as described in NRC Management Directive 8.4, “Management of Backfitting, Forward Fitting, Issue Finality, and Information Requests” (ADAMS Accession No. ML18093B087); does not constitute forward fitting as that term is defined and described in Management Directive 8.4; and does not affect the issue finality of any approval issued under 10 CFR part 52, “Licenses, Certificates, and Approvals for Nuclear Power Plants.” As explained in this RG, applicants and licensees are not required to comply with the positions set forth in this RG.

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    Dated: December 21, 2020.

    For the Nuclear Regulatory Commission.

    Robert G. Roche-Rivera,

    Acting Chief, Regulatory Guidance and Generic Issues Branch, Division of Engineering, Office of Nuclear Regulatory Research.

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    [FR Doc. 2020-28632 Filed 12-28-20; 8:45 am]

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