2020-03237. An Approach for Plant-Specific, Risk-Informed Decisionmaking: Technical Specifications

AGENCY:

Nuclear Regulatory Commission.

ACTION:

Draft regulatory guide; request for comment.

SUMMARY:

The U.S. Nuclear Regulatory Commission (NRC) is re-issuing for public comment draft regulatory guide (DG), DG-1287, “An Approach for Plant-Specific, Risk-Informed Decisionmaking: Technical Specifications.” This proposed Revision 2 of Regulatory Guide (RG) 1.177 includes guidance to develop risk-informed applications for technical specification (TS) changes that considers engineering issues and applies risk insights. This proposed revision also provides guidance acceptable to the staff for using risk information to evaluate changes to nuclear power plant TS completion times (CTs) and surveillance frequencies (SFs) and to assess the impact of such proposed changes on the risk associated with plant operation. This DG-1287 supplements the guidance provided in RG 1.174, “An Approach for Using Probabilistic Risk Assessment in Risk-Informed Decisions on Plant-Specific Changes to the Licensing Basis,” Revision 3, issued January 2018.

DATES:

Submit comments by April 20, 2020. Comments received after this date will be considered if it is practical to do so, but the NRC is able to ensure consideration only for comments received on or before this date.

Although a time limit is given for public comment, comments and suggestions in connection with items for inclusion in RGs currently being developed or improvements in all published RGs are encouraged at any time.

ADDRESSES:

You may submit comments by 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 NRC docket IDs in Regulations.gov to Jennifer Borges; telephone: [phone]; email: [e-mail]. For technical questions, contact the individuals listed in the FOR FURTHER INFORMATION CONTACT section of this document.
• Mail comments to: Office of Administration, Mail Stop: TWFN-7-A60M, U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, ATTN: Program Management, Announcements and Editing Staff.

For additional direction on obtaining information and submitting comments, see “Obtaining Information and Submitting Comments” in the SUPPLEMENTARY INFORMATION section of this document.

FOR FURTHER INFORMATION CONTACT:

Gary Wang, telephone: [phone], email: [e-mail]; or Harriet Karagiannis, telephone: [phone], email: [e-mail]. Both are staff of the Office of Nuclear Regulatory Research, U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001.

SUPPLEMENTARY INFORMATION:

I. Obtaining Information and Submitting Comments

A. Obtaining Information

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

• Federal Rulemaking Website: Go to https://www.regulations.gov and search for Docket ID NRC-2012-0110.
• 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 [e-mail]. The DG is electronically available in ADAMS under Accession No. ML19206A489.
• NRC's PDR: You may examine and purchase copies of public documents at the NRC's PDR, Room O1-F21, One White Flint North, 11555 Rockville Pike, Rockville, Maryland 20852.

B. Submitting Comments

Please include Docket ID NRC-2012-0110 in your comment submission.

The NRC cautions you not to include identifying or contact information that you do not want to be publicly disclosed in your comment submission. The NRC will post all comment submissions at https://www.regulations.gov as well as enter the comment submissions into ADAMS. The NRC does not routinely edit comment submissions to remove identifying or contact information.

If you are requesting or aggregating comments from other persons for submission to the NRC, then you should inform those persons not to include identifying or contact information that they do not want to be publicly disclosed in their comment submission. Your request should state that the NRC does not routinely edit comment submissions to remove such information before making the comment submissions available to the public or entering the comment into ADAMS.

II. Additional Information

The NRC is issuing for public comment a DG 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 NRC's regulations, techniques that the staff uses in evaluating specific issues or postulated events, and data that the staff needs in its review of applications for permits and licenses.

This DG, identified by its task number, DG-1287, titled, “An Approach for Plant-Specific, Risk-Informed Decisionmaking: Technical Specifications,” is a proposed Revision 2 of RG 1.177, “An Approach for Plant-Specific, Risk-Informed Decisionmaking: Technical Specifications.”

A previous version of DG-1287 (ADAMS Accession No. ML12017A054) was issued for public comment in 2012 (77 FR 29391). Commenters on the previous version are encouraged to review and comment on this version, but previously submitted comments will not be explicitly reconsidered for this revised draft guide because of the extent of the changes between this draft guide and the previously published version.

This Revision 2 of RG 1.177 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 RG 1.174 in several staff regulatory positions. Additionally, the staff revised this guide to (1) adopt the term “PRA acceptability,” and related phrasing variants, instead of terms such as “PRA quality,” “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, and (3) delineate the difference between temporary CT extensions and permanent CT extensions of TS or maximum backstop CTs.

III. Backfitting, Issue Finality, and Forward Fitting

RG 1.177, Revision 2, would provide updated guidance for power reactor applicants and licensees regarding use of the defense-in-depth philosophy with other recently updated guidance, and would make other conforming changes to the use of PRA and other terminology. Issuance of this RG in final form would not constitute backfitting or forward fitting or affect issue finality as further discussed below.

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 discussed below—were intended to apply to every NRC action which substantially changes the expectations of current and future applicants.

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 draft RG (if finalized) 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 draft RG (if finalized) 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 draft RG (if finalized) in a manner that would constitute forward fitting. If, in the future, the staff seeks to impose a position in the draft RG (if finalized) in a manner that constitutes forward fitting, then the staff would need to address the forward fitting criteria in Management Directive 8.4.

Dated at Rockville, Maryland, this 13th day of February, 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.