82 FR 17042 - An Approach for Using Probabilistic Risk Assessment in Risk-Informed Decisions on Plant-Specific Changes to the Licensing Basis

NUCLEAR REGULATORY COMMISSION

Federal Register Volume 82, Issue 66 (April 7, 2017)

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.

[Federal Register Volume 82, Number 66 (Friday, April 7, 2017)]
[Notices]
[Pages 17042-17044]
From the Federal Register Online  [www.thefederalregister.org]
[FR Doc No: 2017-06939]


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NUCLEAR REGULATORY COMMISSION

[NRC-2012-0110]


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

AGENCY: Nuclear Regulatory Commission.

ACTION: Draft regulatory guide; request for comment.

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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

[[Page 17043]]

public 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: [email protected]. 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.

FOR FURTHER INFORMATION CONTACT: Anders Gilbertson, Telephone: 301-415-
1541, email: [email protected], and Harriet Karagiannis, 
Telephone: 301-415-2493, email: [email protected]. Both are 
staff members 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 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 [email protected]. 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

[[Page 17044]]

comment 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.

    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.
[FR Doc. 2017-06939 Filed 4-6-17; 8:45 am]
 BILLING CODE 7590-01-P