Skip to Content

Notice

An Approach for Using Probabilistic Risk Assessment in Risk-Informed Decisions on Plant-Specific Changes to the Licensing Basis

Document Details

Information about this document as published in the Federal Register.

Enhanced Content

Relevant information about this document from Regulations.gov provides additional context. This information is not part of the official Federal Register document.

Published Document

This document has been published in the Federal Register. Use the PDF linked in the document sidebar for the official electronic format.

Start Preamble

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-1285, “An Approach for Using Probabilistic Risk Assessment in Risk-Informed Decisions on Plant-Specific Changes to the Licensing Basis.” The guide was initially issued for public comment in 2012 as noticed in the Federal Register under NRC Docket number NRC-2012-0110. Subsequently, the NRC decided to incorporate additional information related to evaluation of the defense-in-depth philosophy that was not included in the original publication of DG-1285. This proposed revision of the guide, Revision 3, includes significant expansion of the guidance on the meaning of, and the process for, assessing the defense-in-depth evaluation factors.

DATES:

Submit comments by May 22, 2017. 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. This Start Printed Page 17043public review and comment period is 45 days. This is shorter than the typical public review and comment period for draft RGs of 60 days because the staff has discussed the defense-in-depth concepts in this RG in numerous public meetings and has addressed multiple comments from the public. Although a time limit is given, comments and suggestions in connection with items for inclusion in guides currently being developed or improvements in all published guides are encouraged at any time.

ADDRESSES:

You may submit comments by any of the following methods:

  • Federal Rulemaking Web site: Go to http://www.regulations.gov and search for Docket ID NRC-2012-0110. Address questions about NRC dockets to Carol Gallagher; telephone: 301-415-3463; email: Carol.Gallagher@nrc.gov. For technical questions, contact the individuals listed in the FOR FURTHER INFORMATION CONTACT section of this document.
  • Mail comments to: Cindy Bladey, Office of Administration, Mail Stop: OWFN-12H08, U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001.

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

Start Further Info

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 members of the Office of Nuclear Regulatory Research, U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001.

End Further Info End Preamble Start Supplemental Information

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 regarding this action. You may obtain publically-available information related to this action, by any of the following methods:

  • Federal Rulemaking Web site: Go to http://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 http://www.nrc.gov/​reading-rm/​adams.html. To begin the search, select “ADAMS Public Documents” and then 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 DG is electronically available in ADAMS under Accession No. ML16358A153.
  • 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 in order to ensure that the NRC is able to make your comment submission available to the public in this docket.

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 posts all comment submissions at http://www.regulations.gov as well as enters 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 submissions 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.

The DG, entitled, “An Approach for Using Probabilistic Risk Assessment in Risk-Informed Decisions on Plant-Specific Changes to the Licensing Basis,” is a proposed revision temporarily identified by its task number, DG-1285. Draft Guide 1285 is proposed revision 3 of RG 1.174, “An Approach for Using Probabilistic Risk Assessment in Risk-Informed Decisions on Plant-Specific Changes to the Licensing Basis.”

This revision proposes revised guidance that uses precise language to assure that the defense-in-depth philosophy is interpreted and implemented consistently, as directed by the Commission in SRM-SECY-11-0014, “Staff Requirements—SECY-11-0014—Use of Containment Accident Pressure in Analyzing Emergency Core Cooling System and Containment Heat Removal System Pump Performance in Postulated Accidents” (see ADAMS under Accession No. ML110740254). Significant changes in this proposed revision include expansion of the guidance on the meaning of, and the process for, assessing the defense-in-depth evaluation factors.

Other changes include the introduction of language for new reactors related to the transitioning from large release frequency and conditional containment failure probability to large early release frequency after fuel loading; introduction of language related to containment performance expectations for new reactors; clarifications related to guidance on the treatment of uncertainty, combining risk results, and the nature of the acceptance guideline boundaries; incorporation of language on defense-in-depth from other NRC guidance documents; and changes to conform to the latest NRC staff program guidance for draft guides.

In addition, the terms “PRA quality” and “technical adequacy” were replaced with the term “PRA acceptability.” The NRC is specifically requesting comment on this terminology changes to ensure the revised terms are clearly understood by the users of the guidance.

The NRC staff conducted four public meetings to solicit public feedback on DG-1285, Revision 3, and keep the public informed regarding the proposed changes regarding defense-in-depth guidance as it was being developed. These public meetings were held on May 2, May 23, July 7, and September 1, and the summaries are available in ADAMS under Accession Nos. ML16148A758, ML16169A343, ML16215A455, and ML162565A448, respectively. Draft versions of the revised guidance on defense-in-depth were made publicly available on May 19, June 20, and July 27, and are available in ADAMS under accession numbers ML16265A451, ML16172A343, and ML16209A221, respectively.

The NRC is issuing for public comment the revised DG-1285 for the reasons mentioned above. Comments received from the public review and Start Printed Page 17044comment period in 2012 were addressed as part of developing this proposed revision of DG-1285. Documentation of the NRC's resolution of public comments on DG-1285 from 2012 are available in ADAMS under Accession No. ML16348A180.

III. Backfitting and Issue Finality

Draft guide 1285 describes an approach that the NRC staff considers acceptable for applications for licensing basis changes by considering engineering issues and applying risk insights at light-water reactors. Issuance of this DG, if finalized, would not constitute backfitting as defined in section 50.109 of title 10 of the Code of Federal Regulations (10 CFR) (the Backfit Rule) and would not otherwise be inconsistent with the issue finality provisions in 10 CFR part 52. As discussed in the “Implementation” section of this DG, the NRC has no current intention to impose this guidance, if finalized, on holders of current operating licenses or combined licenses.

This DG may be applied to applications for amendments to operating licenses or combined licenses docketed by the NRC as of the date of issuance of the final regulatory guide, as well as future applications submitted after the issuance of the regulatory guide. Such action would not constitute backfitting as defined in the Backfit Rule or be otherwise inconsistent with the applicable issue finality provision in 10 CFR part 52, inasmuch as such applicants or potential applicants are not within the scope of entities protected by the Backfit Rule or the relevant issue finality provisions in part 52.

Start Signature

Dated at Rockville, Maryland, this 3rd day of April 2017.

For the Nuclear Regulatory Commission.

Thomas H. Boyce,

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

End Signature End Supplemental Information

[FR Doc. 2017-06939 Filed 4-6-17; 8:45 am]

BILLING CODE 7590-01-P