[Federal Register Volume 91, Number 160 (Thursday, August 20, 2026)]
[Notices]
[Pages 53903-53905]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2026-17013]
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NUCLEAR REGULATORY COMMISSION
[NRC-2022-0052]
Regulatory Guide: Acceptability of Probabilistic Risk Assessment
Results for Non-Light Water Reactor Risk-Informed Activities
AGENCY: Nuclear Regulatory Commission.
ACTION: Trial guide; request for comment.
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SUMMARY: The U.S. Nuclear Regulatory Commission (NRC) is issuing for
trial use, Revision 1 to Trial Regulatory Guide (RG) 1.247,
``Acceptability of Probabilistic Risk Assessment Results for Non-Light
Water Reactor Risk-Informed Activities.'' This guidance describes one
acceptable approach for determining whether the acceptability of the
probabilistic risk assessment (PRA) used to support a PRA application
is sufficient to provide confidence in the results for non-light water
reactors (NLWRs) and risk-informed activities. Trial RG 1.247 was
originally issued in March 2022 with a 2-year trial period that ended
in May 2024. The staff is issuing Revision 1 to RG 1.247 (with minimal
changes) as a trial RG so that it can continue to be used by potential
applicants while the staff addresses the remaining technical issues
that are best resolved by continuing to test the guide against actual
applications. As a trial RG, this issuance does not provide final staff
positions and the guidance within may be revised based on experience
obtained by the NRC with its use after its publication.
DATES: Submit comments by October 19, 2026. Comments received during
this public comment period will be considered and responded to. The
public comment period will be followed by a 3-year trial use period. At
any time during the trial use period, a member of the public may submit
suggestions to the NRC for improvement of existing RGs or for the
development of new RGs. Suggestions can be submitted on the NRC's
public website at https://www.nrc.gov/reading-rm/doc-collections/reg-guides/contactus.html. Suggestions will be considered in future updates
and enhancements to the ``Regulatory Guide'' series. This trial use
period may be extended, as necessary, based on the experience obtained.
After the trial use period, the NRC staff will develop and issue a
draft RG that will include the stakeholder feedback and experience
gained from use of the trial RG. The draft RG issuance will also
provide an additional formal public comment opportunity, with feedback
considered prior to final RG publication.
ADDRESSES: You may submit comments by any of the following methods;
however, the NRC encourages electronic comment submission through the
Federal rulemaking website:
Federal Rulemaking Website: Go to https://www.regulations.gov and search for Docket ID NRC-2022-0052. Address
[[Page 53904]]
questions about Docket IDs in Regulations.gov to Bridget Curran;
telephone: 301-415-1003; email: [email protected]. For technical
questions, contact the individual(s) listed in the FOR FURTHER
INFORMATION CONTACT section of this document.
Mail comments to: Office of Nuclear Material Safety and
Safeguards, Mail Stop: TWFN-5-A85, U.S. Nuclear Regulatory Commission,
Washington, DC 20555-0001, ATTN: Guidance and Publications Branch.
For additional direction on accessing information and submitting
comments, see ``Obtaining Information and Submitting Comments'' in the
SUPPLEMENTARY INFORMATION section of this document.
FOR FURTHER INFORMATION CONTACT: Donna Williams, U.S. Nuclear
Regulatory Commission, Washington, DC 20555-0001; telephone: 301-415-
1322; email: [email protected].
SUPPLEMENTARY INFORMATION:
I. Obtaining Information and Submitting Comments
A. Obtaining Information
Please refer to Docket ID NRC-2022-0052 when contacting the NRC
about the availability of information regarding 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-2022-0052.
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 ADAMS Public Search.''
For problems with ADAMS, please contact the NRC's Public Document Room
(PDR) reference staff at 1-800-397-4209, at 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.
NRC's PDR: The PDR, where you may examine and order copies
of publicly available documents, is open by appointment. To make an
appointment to visit the PDR, please send an email to
[email protected] or call 1-800-397-4209 or 301-415-4737, between 8
a.m. and 4 p.m. eastern time (ET), Monday through Friday, except
Federal holidays.
B. Submitting Comments
The NRC encourages electronic comment submission through the
Federal rulemaking website (https://www.regulations.gov). Please
include Docket ID NRC-2022-0052 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 posts all comment submissions at https://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 trial use Revision 1 to Trial RG 1.247 in
the NRC's ``Regulatory Guide'' series. This series was developed to
describe methods that are acceptable to the NRC staff for implementing
specific parts of the agency's regulations, to explain techniques that
the staff uses in evaluating specific issues or postulated events, and
to describe information that the staff needs in its review of
applications for permits and licenses.
This trial RG titled, ``Acceptability of Probabilistic Risk
Assessment Results for Non-Light Water Reactor Risk-Informed
Activities,'' is designated as Revision 1 to trial use RG 1.247 and is
available in ADAMS under Accession No. ML26132A266.
It describes one acceptable approach for determining whether the
acceptability of the PRA used to support an application is sufficient
to provide confidence in the results, such that the PRA can be used in
regulatory decision-making for NLWRs for implementing the requirements
in part 50, and 52 of title 10 of the Code of Federal Regulations (10
CFR), or future applicable regulations. In addition, Trial RG 1.247
Revision 1 is intended to be consistent with the NRC's PRA Policy
Statement and reflects, and endorses, with staff exceptions and
clarifications, national consensus PRA standards provided by standards
development organizations and guidance provided by nuclear industry
organizations.
On March 24, 2022, the NRC issued Trial RG 1.247 with a 2-year
trial period that ended in May 2024 (87 FR 16770). Revision 1 to Trial
RG 1.247 is being issued as a trial RG with minimal changes so that it
can continue to be used by potential applicants while the staff
addresses the remaining technical issues that are best resolved by
continuing to test the guide against actual applications. The staff has
determined that additional implementation experience would better
inform draft and final staff positions. Such revisions would involve
the development of a draft RG that would include lessons learned and
public comments from use of this trial RG. The draft RG would also be
available for public comment prior to issuance of a final RG.
Therefore, the staff positions included in this trial RG could be
different than the ones that would be included in the draft and final
RG.
The staff previously issued a regulatory analysis (ADAMS Accession
No. ML21235A010) with the original issuance of Trial RG 1.247 that
remains applicable to the issuance of Revision 1. The staff develops a
regulatory analysis to assess the value of issuing this new regulatory
guide as well as alternative courses of action.
III. Backfitting, Forward Fitting, and Issue Finality
This trial RG does not establish a staff position for purposes of
10 CFR 50.109, ``Backfitting'' or constitute forward fitting as that
term is defined and described in NRC Management Directive (MD) 8.4,
``Management of Backfitting, Forward Fitting, Issue Finality, and
Information Requests'' (ADAMS Accession No. ML18093B087). Any changes
to this trial RG, such as withdrawal or addition of or modification to
staff positions based on experience gained during the trial use period,
prior to issuing a final RG will not be considered to be backfitting as
defined in 10 CFR 50.109. This will ensure that the lessons learned
from the regulatory trial use of the pilot applications of this RG are
adequately addressed and that this guidance is sufficient to enhance
regulatory stability in the review and approval of risk-informed
applications for non-light water reactors.
IV. Congressional Review Act
This trial RG is a rule as defined in the Congressional Review Act
(5 U.S.C.
[[Page 53905]]
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.
V. Submitting Suggestions for Improvement of Regulatory Guides
A member of the public may, at any time, submit suggestions to the
NRC for improvement of existing RGs or for the development of new RGs.
Suggestions can be submitted on the NRC's public website at https://www.nrc.gov/reading-rm/doc-collections/reg-guides/contactus.html.
Suggestions will be considered in future updates and enhancements to
the ``Regulatory Guide'' series.
VI. Executive Order (E.O.) 12866
The Office of Information and Regulatory Affairs determined that
this trial RG is not a significant regulatory action under E.O. 12866.
Authority: 42 U.S.C. 2011 et seq.
Dated: August 18, 2026.
For the Nuclear Regulatory Commission.
Nicholee Valentine,
Chief, Guidance and Publications Branch, Division of Guidance,
Rulemaking, Economic Analysis and Technical Editing, Office of Nuclear
Material Safety and Safeguards.
[FR Doc. 2026-17013 Filed 8-19-26; 8:45 am]
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