[Federal Register Volume 88, Number 160 (Monday, August 21, 2023)]
[Notices]
[Pages 56885-56887]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2023-17401]
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NUCLEAR REGULATORY COMMISSION
[NRC-2023-0140]
Level 3 Probabilistic Risk Assessment Project Documentation
(Volume 4)
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 4:
[[Page 56886]]
Overview of Reactor, At-Power, Level 1, 2, and 3 PRAs for Internal
Fires, Seismic Events, and High Winds.''
DATES: Submit comments by October 20, 2023. 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-2023-0140. Address
questions about Docket IDs in Regulations.gov to Stacy Schumann;
telephone: 301-415-0624; email: [email protected]. For technical
questions, contact the individual listed in the For Further Information
Contact section of this document.
Mail comments to: Office of Administration, Mail Stop:
TWFN-7-A60M, 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 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-2023-0140 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-2023-0140.
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 Web-based ADAMS
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-2023-0140 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 is conducting 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 two 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. This second batch of Level 3 PRA project reports
describes the analyses and results for the reactor, at-power, Level 1,
2, and 3 PRAs for internal fires, seismic events, and high winds
(Volume 4). Each set of Level 3 PRA project reports covering the Level
1, 2, and 3 PRAs for a specific site radiological source, plant
operating state, and hazard group (or groups) is accompanied by an
overview report. The overview reports summarize the results and
insights from all three PRA levels.
The Level 3 PRA project analyses reflect the reference plant as it
was designed and operated as of 2012. To provide results and insights
better aligned with the current design and operation of the reference
plant, the overview reports also provide a reevaluation of the plant
risk based on a set of new plant equipment and PRA model assumptions
and compare the results of the reevaluation to the original study
results. This reevaluation reflects the current reactor coolant pump
shutdown seal design at the reference plant, as well as the potential
impact of FLEX strategies, both of which reduce the risk to the public.
As documented in Section 2 of the Volume 4 overview report, the
results of the original Level 3 PRA project analyses and the
reevaluation both show that, when considering all hazards combined for
the reactor at power, the combination of this plant design and site
location has substantial margin to the quantitative health objectives
related to the NRC's safety goal policy, though the margins are
noticeably less for the surrogate risk metrics of core damage frequency
and large, early release frequency. Even though these margins can vary
for other plants due to variations in their design and siting, the
estimates derived for the reference
[[Page 56887]]
plant, when adjusted for siting and design variations, would provide
useful qualitative risk insights for other U.S. operating plants.
III. Availability of Documents
The documents identified in the following table are available to
interested persons through ADAMS, as indicated.
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ADAMS accession
Document description No.
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SRM-SECY-11-0089, ``Options for Proceeding with ML112640419
Future Level 3 Probabilistic Risk Assessment (PRA)
Activities''........................................
Level 3 PRA Project, Volume 4: Overview of Reactor, ML23194A015
At-Power, Level 1, 2, and 3 PRAs for Internal Fires,
Seismic Events, and High Winds; Draft Report for
Comment.............................................
Level 3 PRA Project, Volume 4a: Reactor, At-Power, ML23194A016
Level 1 PRA for Internal Fires......................
Level 3 PRA Project, Volume 4b: Reactor, At-Power, ML23194A017
Level 1 PRA for Seismic Events......................
Level 3 PRA Project, Volume 4c: Reactor, At-Power, ML23194A012
Level 1 PRA High Winds and Other Hazards............
Level 3 PRA Project, Volume 4d: Reactor, At-Power, ML23194A013
Level 2 PRA for Internal Fires, Seismic Events, and
High Winds..........................................
Level 3 PRA Project, Volume 4e: Reactor, At-Power, ML23194A014
Level 3 PRA for Internal Fires, Seismic Events, and
High Winds..........................................
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Dated: August 9, 2023.
For the Nuclear Regulatory Commission.
Jonathan E. Evans,
Chief, Probability Risk Assessment Branch, Division of Risk Analysis,
Office of Nuclear Regulatory Research.
[FR Doc. 2023-17401 Filed 8-18-23; 8:45 am]
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