[Federal Register Volume 86, Number 12 (Thursday, January 21, 2021)]
[Pages 6375-6376]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2021-01154]




An Approach for Plant-Specific, Risk-Informed Decisionmaking: 
Technical Specifications

AGENCY: Nuclear Regulatory Commission.

ACTION: Regulatory guide; issuance.


SUMMARY: The U.S. Nuclear Regulatory Commission (NRC) is issuing 
Revision 2 to Regulatory Guide (RG) 1.177, ``An Approach for Plant-
Specific, Risk-Informed Decisionmaking: Technical Specifications.'' 
Revision 2 of RG 1.177 includes guidance to develop risk-informed 
applications for technical specification (TS) changes that considers 
engineering issues and applies risk insights. It provides guidance 
acceptable to the staff for using risk information to evaluate changes 
to nuclear power plant TS completion times (CTs), surveillance 
frequencies (SFs) and to assess the impact of such proposed changes on 
the risk associated with plant operation. In addition, it supplements 
RG 1.174, Revision 3, ``An Approach for Using Probabilistic Risk 
Assessment in Risk-Informed Decisions on Plant-Specific Changes to the 
Licensing Basis,''.

DATES: Revision 2 to RG 1.177 is available on January 21, 2021.

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: [email protected]. 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 [email protected].
     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 [email protected] or call 1-800-397-4209 or 
301-415-4737, between 8:00 a.m. and 4:00 p.m. (EST), Monday through 
Friday, except Federal holidays.
    Revision 2 to RG 1.177 and the regulatory analysis may be found in 
ADAMS under Accession Nos. ML20164A034 and ML19206A493, respectively.
    Regulatory guides are not copyrighted, and NRC approval is not 
required to reproduce them.

FOR FURTHER INFORMATION CONTACT: Gary Wang, telephone: 301-415-1686, 
email: [email protected]; or Harriet Karagiannis, telephone: 301-
415-2493, email: [email protected]. Both are staff of the 
Office of Nuclear Regulatory Research, U.S. Nuclear Regulatory 
Commission, Washington, DC 20555-0001.


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 uses 
in its review of applications for permits and licenses.
    Revision 2 of RG 1.177 was issued with a temporary identification 
of Draft Regulatory Guide, DG-1287. It updates the application of the 
defense-in-depth philosophy to be consistent with the philosophy 
described in RG 1.174, which was revised in 2018 to expand the meaning 
of, and the process for, assessing defense-in-depth considerations. 
Specifically, this revision of RG 1.177 references the defense-in-depth 
guidance in the revised RG 1.174 with respect to several staff 
regulatory positions. Additionally, the staff revised this guide to (1) 
adopt the terms ``PRA acceptability,'' and related phrasing variants, 
instead of terms such as ``PRA quality,'' and ``PRA technical 
adequacy,'' and ``technical adequacy'' to describe the appropriateness 
of the probabilistic risk analysis (PRA) used to support risk informed 
licensing submittals, (2) update Section 2.3, ``Evaluation of Risk 
Impact,'' of RG 1.177 by removing information that was repeated from RG 
1.174 (e.g., discussion of the ASME/ANS PRA standard) and, in its 

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incorporated a direct reference to RG 1.174, Revision 3, and (3) 
delineate the difference between temporary CT extensions and permanent 
CT extensions of TSs or maximum backstop CTs.

II. Additional Information

    The NRC published a notice of the availability of DG-1287 (ADAMS 
under Accession No. ML19206A489), in the Federal Register on February 
19, 2020 (85 FR 9484) for a 60-day public comment period. The public 
comment period closed on April 20, 2020, and the NRC received two 
comment documents. Public comments on DG-1287 and the staff responses 
to the public comments are available in ADAMS under Accession No. 

II. 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.

III. Backfitting, Forward Fitting, and Issue Finality

    RG 1.177, Revision 2 provides updated guidance for power reactor 
applicants and licensees regarding the use of the defense-in-depth 
philosophy with other recently updated guidance and would make other 
conforming changes to the use of PRA and associated terminology. 
Issuance of this RG does not constitute backfitting or forward fitting 
or affect issue finality as further discussed in this notice.
    Current or future applicants are not, with limited exceptions not 
applicable here, within the scope of the backfitting and issue finality 
regulations and forward fitting policy. Applicants are not, with 
certain exceptions, covered by either the backfit rule or any issue 
finality provisions under part 52 of title 10 of the Code of Federal 
Regulations (10 CFR). This is because neither the backfit rule nor the 
issue finality provisions under 10 CFR part 52, with certain exclusions 
further discussed, were intended to apply to every NRC action which 
substantially changes the expectations of current and future 
    The exceptions to the general principle are applicable whenever an 
applicant references a 10 CFR part 52 license (e.g., an early site 
permit) and/or NRC regulatory approval (e.g., a design certification 
rule) with specified issue finality provisions or a construction permit 
under 10 CFR part 50. The staff does not, at this time, intend to 
impose the positions represented in the RG in a manner that would 
constitute backfitting or affect the issue finality of a part 52 
approval. If, in the future, the staff seeks to impose a position in 
the RG in a manner that constitutes backfitting or does not provide 
issue finality as described in the applicable issue finality provision, 
then the staff would need to address the backfit rule or the criteria 
for avoiding issue finality as described in the applicable issue 
finality provision.
    The staff does not, at this time, intend to impose the positions 
represented in the RG in a manner that would constitute forward 
fitting. If, in the future, the staff seeks to impose a position in the 
RG in a manner that constitutes forward fitting, then the staff would 
need to address the forward fitting criteria in Management Directive 
8.4, ``Management of Backfitting, Forward Fitting, Issue Finality, and 
Information Requests'' (ADAMS Accession No. ML18093B087).

    Dated: January 13, 2020.

    For the Nuclear Regulatory Commission.
Meraj Rahimi,
Chief, Regulatory Guidance and Generic Issues Branch, Division of 
Engineering, Office of Nuclear Regulatory Research.
[FR Doc. 2021-01154 Filed 1-19-21; 8:45 am]