Notice2026-19300
Regulatory Guides: Design-Basis Floods for Nuclear Power Plants and Guidance for Assessment of Flooding Hazards Due to Water Control Structure Failures and Incidents
Primary source
Metadata and text below are from the Federal Register, a public-domain U.S. government work. Always verify the official published version before relying on it for any legal matter.
Published
September 22, 2026
Issuing agencies
Nuclear Regulatory Commission
Abstract
The U.S. Nuclear Regulatory Commission (NRC) is issuing two related Regulatory Guides (RGs), namely RG 1.59, Revision 3, "Design- Basis Floods for Nuclear Power Plants," and RG 1.256, Revision 0, "Guidance for Assessment of Flooding Hazards due to Water Control Structure Failures and Incidents." RG 1.59 provides guidance for applicants for new nuclear power plants on acceptable methods for evaluating design-basis floods and RG 1.256 provides guidance for applicants on methods for evaluating flooding hazards due to failure or other incidents at man-made water control structures including, but not limited to, dams and levees.
Full Text
<html>
<head>
<title>Federal Register, Volume 91 Issue 182 (Tuesday, September 22, 2026)</title>
</head>
<body><pre>
[Federal Register Volume 91, Number 182 (Tuesday, September 22, 2026)]
[Notices]
[Pages 60157-60158]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2026-19300]
-----------------------------------------------------------------------
NUCLEAR REGULATORY COMMISSION
[NRC-2024-0110]
Regulatory Guides: Design-Basis Floods for Nuclear Power Plants
and Guidance for Assessment of Flooding Hazards Due to Water Control
Structure Failures and Incidents
AGENCY: Nuclear Regulatory Commission.
ACTION: Final guide, issuance.
-----------------------------------------------------------------------
SUMMARY: The U.S. Nuclear Regulatory Commission (NRC) is issuing two
related Regulatory Guides (RGs), namely RG 1.59, Revision 3, ``Design-
Basis Floods for Nuclear Power Plants,'' and RG 1.256, Revision 0,
``Guidance for Assessment of Flooding Hazards due to Water Control
Structure Failures and Incidents.'' RG 1.59 provides guidance for
applicants for new nuclear power plants on acceptable methods for
evaluating design-basis floods and RG 1.256 provides guidance for
applicants on methods for evaluating flooding hazards due to failure or
other incidents at man-made water control structures including, but not
limited to, dams and levees.
DATES: RG 1.59, Revision 3 and RG 1.256, Revision 0 are available on
September 22, 2026.
ADDRESSES: Please refer to Docket ID NRC-2024-0110 when contacting the
NRC about the availability of information regarding these documents.
You may obtain publicly available information related to these
documents using any of the following methods:
<bullet> Federal Rulemaking Website: Go to <a href="https://www.regulations.gov">https://www.regulations.gov</a> and search for Docket ID NRC-2024-0110. Address
questions about Docket IDs in <a href="http://Regulations.gov">Regulations.gov</a> to Bridget Curran;
telephone: 301-415-1003; email: <a href="/cdn-cgi/l/email-protection#a6e4d4cfc2c1c3d288e5d3d4d4c7c8e6c8d4c588c1c9d0"><span class="__cf_email__" data-cfemail="0b4979626f6c6e7f25487e79796a654b657968256c647d">[email protected]</span></a>. For technical
questions, contact the individual(s) listed in the FOR FURTHER
INFORMATION CONTACT section of this document.
<bullet> NRC's Agencywide Documents Access and Management System
(ADAMS): You may obtain publicly available documents online in the
ADAMS Public Documents collection at <a href="https://www.nrc.gov/reading-rm/adams.html">https://www.nrc.gov/reading-rm/adams.html</a>. 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 <a href="/cdn-cgi/l/email-protection#e3b3a7b1cdb186908c96918086a38d9180cd848c95"><span class="__cf_email__" data-cfemail="9ecedaccb0ccfbedf1ebecfdfbdef0ecfdb0f9f1e8">[email protected]</span></a>. 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.
<bullet> 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
<a href="/cdn-cgi/l/email-protection#4a1a0e1864182f39253f38292f0a243829642d253c"><span class="__cf_email__" data-cfemail="174753453945726478626574725779657439707861">[email protected]</span></a> 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.
RG 1.59, Revision 3 and its regulatory analysis may be found in
ADAMS under Accession No. ML19289E563. RG 1.256, Revision 0 and its
regulatory analysis may be found at ML22278A111.
Regulatory guides are not copyrighted, and NRC approval is not
required to reproduce them.
FOR FURTHER INFORMATION CONTACT: James Steckel, Office of Nuclear
Material Safety and Safeguards, telephone: 301-415-1026; email:
<a href="/cdn-cgi/l/email-protection#efa58e828a9cc1bc9b8a8c848a83af819d8cc1888099"><span class="__cf_email__" data-cfemail="bef4dfd3dbcd90edcadbddd5dbd2fed0ccdd90d9d1c8">[email protected]</span></a> and Joseph Kanney, Office of Nuclear Regulatory
Research, telephone: 301-415-1920; email: <a href="/cdn-cgi/l/email-protection#4c06233f293c2462072d222229350c223e2f622b233a"><span class="__cf_email__" data-cfemail="044e6b7761746c2a4f656a6a617d446a76672a636b72">[email protected]</span></a>. Both
are staff of the U.S. Nuclear Regulatory Commission, Washington, DC
20555-0001.
SUPPLEMENTARY INFORMATION:
I. Discussion
The NRC is issuing two related RGs 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 uses in its review of applications for
permits and licenses.
RG 1.59, Revision 3, reflects lessons learned from the review of
large light water nuclear power plant applications under part 52 of
title 10 of the Code of Federal Regulations (10 CFR) since the issuance
of RG 1.59, Revision 2, in August 1977, as well as additional lessons
learned from staff reviews of licensees' responses to the NRC's
``Request for Information Pursuant to Title 10 of the Code of Federal
Regulations 50.54(f) Regarding Recommendations 2.1, 2.3, and 9.3, of
the Near Term Task Force Review of Insights from the Fukushima Dai-ichi
Accident.'' The body of this RG applies to large light water reactors.
In view of the emerging innovations taking place in nuclear engineering
science, Appendix K is presented as an alternative approach for
advanced reactors, which may be used in conjunction with the guidance
in RG 1.247, ``Acceptability of Probabilistic Risk Assessment Results
for Non-Light
[[Page 60158]]
Water Reactor Risk-Informed Activities.''
RG 1.256, Revision 0 provides guidance to applicants for new
nuclear power plants on acceptable methods for evaluating design-basis
flooding hazards due to failure or other incidents at man-made water
control structures including, but not limited to, dams and levees. The
RG was developed primarily for use by new nuclear power plant
applicants, but current licensees may also find it useful. It
incorporates NRC interim staff guidance JLD-ISG-2013-01 ``Guidance for
Assessment of Flooding Hazards Due to Dam Failure,'' into the NRC's
regulatory framework. Upon issuance of Revision 0 of RG 1.256, JLD-
2013-01 will be withdrawn.
II. Additional Information
The two RGs were released for public comment via a notice in the
Federal Register on July 15, 2024 (89 FR 57372) as Draft Guide (DG)-
1290, Revision 1 for RG 1.59, Revision 3, and DG-1417 for RG 1.256,
Revision 0. The comment period was originally for 30 days and was
subsequently extended to September 13, 2024. Comments were received
from the Nuclear Energy Institute. The comments on DG-1290, Revision 1
and the staff response to them are available in ADAMS under Accession
No. ML26246A471. The comments on DG-1417 and the staff response to them
are available in ADAMS under Accession No. ML26258A151.
III. Congressional Review Act
These RGs are both considered to be 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 them to be a major rule as defined
in the Congressional Review Act.
IV. Backfitting, Forward Fitting, and Issue Finality
The NRC staff may use RG 1.59, Revision 3, and RG 1.256, Revision
0, as references in its regulatory processes, such as licensing,
inspection, or enforcement. However, the NRC staff does not intend to
use the guidance in RG 1.59 and RG 1.256 to support NRC staff actions
in a manner that would constitute backfitting as that term is defined
in 10 CFR 50.109, ``Backfitting,'' and as described in NRC Management
Directive (MD) 8.4, ``Management of Backfitting, Forward Fitting, Issue
Finality, and Information Requests,'' (ADAMS Accession No.
ML18093B087); nor does the NRC staff intend to use the guidance to
affect the issue finality of an approval under 10 CFR part 52,
``Licenses, Certifications, and Approvals for Nuclear Power Plants.''
The staff also does not intend to use the guidance to support NRC staff
actions in a manner that constitutes forward fitting as that term is
defined and described in MD 8.4. If a licensee believes that the NRC is
using these RGs in a manner inconsistent with the discussion in this
Implementation section, then the licensee may file a backfitting or
forward fitting appeal with the NRC in accordance with the process in
MD 8.4.
V. Submitting Suggestions for Improvement of Regulatory Guides
A member of the public may, at any time, submit suggestions to the
NRC for the improvement of existing RGs or for the development of new
RGs. Suggestions can be submitted on the NRC's public website at
<a href="https://www.nrc.gov/reading-rm/doc-collections/reg-guides/contactus.html">https://www.nrc.gov/reading-rm/doc-collections/reg-guides/contactus.html</a>. Suggestions will be considered in future updates and
enhancements to the ``Regulatory Guide'' series.
VI. Executive Order (E.O.) 12866
The Office of Management and Budget, Office of Information and
Regulatory Affairs determined that RG 1.59, Revision 3 and RG 1.256,
Revision 0 are not a significant regulatory action under E.O. 12866.
Authority: 42 U.S.C. 2011 et seq.
Dated: September 17, 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 and Safety and Safeguards.
[FR Doc. 2026-19300 Filed 9-21-26; 8:45 am]
BILLING CODE 7590-01-P
</pre><script data-cfasync="false" src="/cdn-cgi/scripts/5c5dd728/cloudflare-static/email-decode.min.js"></script></body>
</html>Indexed from Federal Register on September 22, 2026.
This is legal information, not legal advice. Laws vary by jurisdiction and change frequently. Always verify current law with official sources and consult a licensed attorney in your jurisdiction for advice on your specific situation.