[Federal Register Volume 83, Number 21 (Wednesday, January 31, 2018)]
[Notices]
[Pages 4520-4521]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2018-01901]
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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: Regulatory guide; issuance.
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SUMMARY: The U.S. Nuclear Regulatory Commission (NRC) is issuing
Revision 3 to Regulatory Guide (RG) 1.174, ``An Approach for Using
Probabilistic Risk Assessment in Risk-Informed Decisions on Plant-
Specific Changes to the Licensing Basis.'' This proposed guide,
Revision 3, has been revised to incorporate additional information
related to the evaluation of defense-in-depth since Revision 2 of RG
1.174 was issued in 2011. The proposed revision includes additional
guidance on defense-in-depth to assure the defense-in-depth philosophy
is interpreted and implemented consistently.
DATES: Revision 3 to RG 1.174 is available on January 31, 2018.
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 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.
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
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. Revision 3 to RG 1.174 and the regulatory analysis may be
found in ADAMS under Accession Nos. ML17317A256 and ML16358A156
respectively.
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.
Regulatory guides are not copyrighted, and NRC approval is not
required to reproduce them.
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 of the Office of Nuclear Regulatory Research, U.S. Nuclear
Regulatory Commission, Washington, DC 20555-0001.
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. Revision 3 of
RG 1.174 describes an approach that is acceptable to the staff of the
NRC when developing risk-informed applications for a licensing basis
change that considers engineering issues and applies risk insights.
Revision 3 of RG 1.174 was issued with a temporary identification
of Draft Regulatory Guide, DG-1285. This revision (Revision 3) presents
up-to-date defense-in-depth guidance using precise language to assure
the defense-in-depth philosophy is interpreted and implemented
consistently. Revision 3 contains significant changes including
expansion of the guidance on the meaning of, and the process for
assessing, the defense-in-depth considerations.
In addition, this revision adopts the term ``PRA Acceptability,''
including related phrasing variants, in place of terms such as ``PRA
quality,'' ``PRA technical adequacy,'' and ``technical
[[Page 4521]]
adequacy'' to describe the appropriateness of the PRA used to support
risk-informed licensing submittals. Other changes in this revision
include expanding the discussions on uncertainties, including
aggregation of risk results, consistent with NUREG-1855, ``Guidance on
the Treatment of Uncertainties Associated with PRAs in Risk-Informed
Decisionmaking'' (ADAMS Accession No. ML17062A466), updating the risk
acceptance guideline figures, and incorporating discussions related to
application of this guide to new reactors.
Regarding the guidance in Section C.6.3 of the guide on the
licensee submittal documentation, the NRC has accepted via a letter
issued on May 3, 2017 (See ADAMS Accession No. ML17079A427), an
industry process entitled ``Close-out of Facts and Observations
(F&Os)'' (See ADAMS Accession No. ML17086A431) that allows a licensee
to formally close F&Os that were generated during a peer review
process. If a licensee meets the conditions of acceptance as described
in the NRC's letter, a licensee does not need to submit the closed F&Os
in any future applications. It should be noted that the NRC position in
the May 3rd letter is expected to be incorporated into the next
revision of RG 1.200, ``An Approach for Determining the Technical
Adequacy of Probabilistic Risk Assessment Results for Risk-Informed
Activities.''
II. Additional Information
The NRC published a notice of the availability of DG-1285 in the
Federal Register on April 7, 2017 (82 FR 17042), for a 45-day public
comment period. The public comment period closed on May 22, 2017.
Public comments on DG-1285 and the staff responses to the public
comments are available under ADAMS under Accession No. ML17261A618.
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 and Issue Finality
RG 1.174 describes an approach that the NRC staff considers
acceptable when developing risk-informed applications for a licensing
basis change that considers engineering issues and applies risk
insights. 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) (the Backfit Rule) and is not otherwise
inconsistent with the issue finality provisions in 10 CFR part 52. As
discussed in the ``Implementation'' section of this RG, the NRC has no
current intention to impose this guidance on holders of current
operating licenses or combined licenses.
This RG may be applied to applications for amendments to operating
licenses or combined licenses docketed by the NRC as of the date of
issuance, as well as future applications submitted after the issuance
of this 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 25th day of January 2018.
For the Nuclear Regulatory Commission.
Edward O'Donnell,
Acting Chief, Regulatory Guidance and Generic Issues Branch, Division
of Engineering, Office of Nuclear Regulatory Research.
[FR Doc. 2018-01901 Filed 1-30-18; 8:45 am]
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