[Federal Register Volume 91, Number 97 (Wednesday, May 20, 2026)]
[Notices]
[Pages 29513-29515]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2026-10074]
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NUCLEAR REGULATORY COMMISSION
[NRC-2026-1453]
Level 3 Probabilistic Risk Assessment Project Documentation
(Volume 1)
AGENCY: Nuclear Regulatory Commission.
ACTION: Draft report; request for comment.
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SUMMARY: The U.S. Nuclear Regulatory Commission (NRC) is issuing for
public comment a draft report on the Level 3 Probabilistic Risk
Assessment (PRA) project; specifically, ``Volume 1: Summary Report.''
DATES: Submit comments by July 20, 2026. Comments received after this
date will be considered if it is practical to do so, but the Commission
is able to ensure consideration only for comments received on or before
this date.
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-2026-1453. Address
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 Administration, Mail Stop:
TWFN-5-A85, 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
[[Page 29514]]
Submitting Comments'' in the SUPPLEMENTARY INFORMATION section of this
document.
FOR FURTHER INFORMATION CONTACT: Alan Kuritzky, Office of Nuclear
Regulatory Research, U.S. Nuclear Regulatory Commission, Washington, DC
20555-0001; telephone: 301-415-1552; email: [email protected].
SUPPLEMENTARY INFORMATION:
I. Obtaining Information and Submitting Comments
A. Obtaining Information
Please refer to Docket ID NRC-2026-1453 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-2026-1453.
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]. For the convenience of the reader,
instructions about obtaining materials referenced in this document are
provided in the ``Availability of Documents'' section.
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-2026-1453 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. Discussion
As directed in SRM-SECY-11-0089, ``Options for Proceeding with
Future Level 3 Probabilistic Risk Assessment (PRA) Activities,'' the
staff conducted a full-scope multi-unit site Level 3 PRA (Level 3 PRA
project) that addresses all internal and external hazards; all plant
operating modes; and all reactor units, spent fuel pools, and dry cask
storage. The reference site for this study contains 2 four-loop
Westinghouse pressurized water reactors with large dry containments.
The objectives of the Level 3 PRA project are to (1) develop a Level 3
PRA, generally based on current state-of-practice methods, tools, and
data, that (a) reflects technical advances since the last NRC-sponsored
Level 3 PRAs (NUREG-1150), which were completed over 30 years ago, and
(b) addresses scope considerations that were not previously considered
(e.g., low-power and shutdown risk, multi-unit risk, other radiological
sources); (2) extract new insights to enhance regulatory decision
making and to help focus limited NRC resources on issues most directly
related to the agency's mission to protect public health and safety;
(3) enhance PRA staff capability and expertise and improve
documentation practices to make PRA information more accessible,
retrievable, and understandable; and (4) demonstrate technical
feasibility and evaluate the realistic cost of developing new Level 3
PRAs.
The work performed under this project is being documented as a
multi-volume report, commensurate with the depth and scope of this
seminal research program. Over the last several years, the staff has
publicly released 21 draft reports that document the various PRA models
developed for the Level 3 PRA project. The current draft report (Volume
1) represents the completion of the Level 3 PRA project and provides a
summary of the entire Level 3 PRA project. This includes the project
scope and objectives, a brief overview of the project technical
approach, and a summary of the principal project results, observations,
and insights. This report also identifies existing and potential future
uses of the project information, as well as a set of candidate areas
for future research.
The Level 3 PRA project represents a significant research effort by
the NRC and was completed in a manner consistent with the overall
project objectives. The project documentation provides a complete
record of project assumptions, modeling approaches, and results, which
was a significant project goal. This study addressed several PRA
modeling gaps, piloted newly developed approaches for expert
elicitation, and included extensive peer reviews supported by the
Advisory Committee on Reactor Safeguards, the Pressurized Water Reactor
Owners Group, and an internal technical advisory group. Stakeholder
comments received during the public comment periods for the previously
released project reports further enhanced the quality of the
documentation. Insights related to this work have supported regulatory
decision-making in several areas and the knowledge management aspects
of conducting the study have prepared the agency to address emerging
PRA challenges in support of risk-informed decision-making.
III. Availability of Documents
The documents identified in the following table are available to
interested persons through ADAMS, as indicated.
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Document description ADAMS accession No.
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SRM-SECY-11-0089, ``Options for ML112640419
Proceeding with Future Level 3
Probabilistic Risk Assessment (PRA)
Activities,'' dated September 21,
2011.
Level 3 PRA Project, Volume 1: Summary ML26078A044
Report (draft for public comment).
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[[Page 29515]]
(Authority: 42 U.S.C. 2011 et seq.)
Dated: May 18, 2026.
For the Nuclear Regulatory Commission.
Jonathan Evans,
Chief, Probabilistic Risk Assessment Branch, Division of Risk Analysis,
Office of Nuclear Regulatory Research.
[FR Doc. 2026-10074 Filed 5-19-26; 8:45 am]
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