[Federal Register Volume 86, Number 227 (Tuesday, November 30, 2021)]
[Notices]
[Pages 67983-67984]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2021-26018]


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NUCLEAR REGULATORY COMMISSION

[NRC-2021-0213]


Target Fragilities for Equipment Vulnerable to High Energy Arcing 
Faults

AGENCY: Nuclear Regulatory Commission.

ACTION: Draft research information letter; request for comment.

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SUMMARY: The U.S. Nuclear Regulatory Commission (NRC) is issuing for 
public comment draft research information letter, ``Target Fragilities 
for Equipment Vulnerable to High Energy Arcing Faults, Draft Report for 
Comment.''

DATES: Submit comments by December 30, 2021. 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-2021-0213. 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: Gabriel J. Taylor, Office of Nuclear 
Regulatory Research, U.S. Nuclear Regulatory Commission, Washington, DC 
20555-0001, telephone: 301-415-0781, email: [email protected].

SUPPLEMENTARY INFORMATION:

I. Obtaining Information and Submitting Comments

A. Obtaining Information

    Please refer to Docket ID NRC-2021-0213 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-2021-0213.
     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, 301-415-4737, or 
by email to [email protected]. The draft Research Information Report 
``Target Fragilities for Equipment Vulnerable to High Energy Arcing 
Faults, Draft Report for Comment'' is available in ADAMS under 
Accession No. ML21326A010.
     NRC's PDR: You may examine and purchase copies of public 
documents, by appointment, at the NRC's PDR, Room P1 B35, One White 
Flint North, 11555 Rockville Pike, Rockville, Maryland 20852. 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 
8:00 a.m. and 4:00 p.m. (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

[[Page 67984]]

Docket ID NRC-2021-0213 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

    The NRC Office of Nuclear Regulatory Research (RES) is advancing 
the understanding and state-of-practice for modeling High Energy Arcing 
Faults (HEAF) in fire Probabilistic Risk Assessment (PRA). One 
important aspect of this research is to understand the HEAF effects on 
equipment important for nuclear safety. The high intensity and short 
duration of a HEAF exposure causes substantially different heat 
transfer conditions than a classical thermal fire case. As such, there 
was a need to develop HEAF specific damage and ignition limits to 
support advancements. The NRC collaborated with the Electric Power 
Research Institute (EPRI) to develop technical consensus positions on 
the damage and ignition limits of equipment important to plant safety 
and commonly evaluated in fire PRAs. The target fragility limits are 
based on operating experience, small and large scale testing, lessons 
learned from a Phenomena Identification and Ranking Table exercise, 
results from analytical tools, and judgement.
    The draft research information letter presents the NRC-RES/EPRI 
working groups consensus on the damage and ignition limits of nuclear 
facility targets that are important to safety. It includes specific 
energy fluence levels that cause damage to components such as 
electrical cables, cable protective features, and non-segregated phase 
bus ducts. The conclusions from this report will be used in conjunction 
with HEAF hazard estimates to develop zones of influence to support 
improvements to fire PRA methods.

    Dated: November 24, 2021.

    For the Nuclear Regulatory Commission.
Mark H. Salley,
Chief, Fire and External Hazards Analysis Branch, Division of Risk 
Analysis, Office of Nuclear Regulatory Research.
[FR Doc. 2021-26018 Filed 11-29-21; 8:45 am]
BILLING CODE 7590-01-P