[Federal Register Volume 87, Number 93 (Friday, May 13, 2022)]
[Notices]
[Pages 29395-29396]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2022-10323]


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NUCLEAR REGULATORY COMMISSION

[NRC-2022-0096]


Modeling High Energy Arcing Fault Hazards and Zones of Influence

AGENCY: Nuclear Regulatory Commission.

ACTION: Draft research information letter reports; request for comment.

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SUMMARY: The U.S. Nuclear Regulatory Commission (NRC) is issuing for 
public comment two draft Research Information Letter reports, 
``Predicting High Energy Arcing Fault Zones of Influence for Aluminum 
Using a Modified Arc Flash Model, Evaluation of a modified model bias, 
uncertainty, parameter sensitivity and zone of influence estimation, 
Draft for public comment,'' and ``Determining the Zone of Influence for 
High Energy Arcing Faults using Fire Dynamics Simulator, Draft for 
public comment.''

DATES: Submit comments by June 13, 2022. 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-2022-0096. 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-2022-0096 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-2022-0096.
     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 letter 
reports ``Predicting High Energy Arcing Fault Zones of Influence for 
Aluminum Using a Modified Arc Flash Model, Evaluation of a modified 
model bias, uncertainty, parameter sensitivity and zone of influence 
estimation, Draft for public comment'' is available in ADAMS under 
Accession No. ML22095A236, and ``Determining the Zone of Influence for

[[Page 29396]]

High Energy Arcing Faults using Fire Dynamics Simulator, Draft for 
public comment,'' is available in ADAMS under Accession No. 
ML22095A237.
     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 Docket ID NRC-2022-0096 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. All comments should 
reference the applicable report.

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 the ability to reliably predict 
the HEAF hazard for various scenarios important for nuclear safety. The 
high intensity and short duration of a HEAF has not been explicitly 
modeled in past fire PRA methodologies. As such, there was a need to 
advance HEAF modeling capabilities to reliably predict the scenario 
specific HEAF hazards to support refinements to the zones of influence 
(ZOI) used in fire PRA. The NRC worked with its collaborative research 
partners to develop two models to predict the HEAF hazard.
    In the report titled, ``Predicting High Energy Arcing Fault Zones 
of Influence for Aluminum Using a Modified Arc Flash Model, Evaluation 
of a modified model bias, uncertainty, parameter sensitivity and zone 
of influence estimation, Draft for public comment,'' the NRC worked 
with Sandia National Laboratories to evaluate an existing base model. 
Differences between the base model and nuclear power plant fire PRA 
scenarios were identified. Modification of the base model established 
from existing literature and test data was used to minimize these 
differences. The modified model was evaluated against NRC datasets to 
understand the model prediction and relative uncertainties. Finally, a 
range of fire PRA ZOIs were developed based on the modified model and 
draft update HEAF PRA methodology. The results are expected to be used 
to inform an update to ZOIs used in fire PRA.
    In the report titled, ``Determining the Zone of Influence for High 
Energy Arcing Faults using Fire Dynamics Simulator, Draft for public 
comment,'' the NRC worked with the Electric Power Research Institute 
and the National Institute of Standards and Technology to adapt a 
computational fluid dynamic code known as the Fire Dynamics Simulator 
(FDS) to predict the HEAF hazard. This report documents (1) the 
development of the approach to use FDS to predict thermal exposures to 
targets from a HEAF, (2) validation of the model and (3) application of 
the model to estimate HEAF ZOI for a broad range of fire PRA HEAF 
scenarios.
    The draft research information letter reports present the NRC-RES/
Sandia National Laboratories (SNL) and NRC-RES/Electric Research Power 
Institute (EPRI) working groups efforts to predict realistic HEAF 
hazards. The two approaches to model HEAF hazards present complementary 
but diverse methods to estimating the hazard ZOI. For most scenarios 
the two approaches provide results that are consistent with each other. 
The NRC-SNL report can be viewed as a first order approximation 
providing a single value scenario specific ZOI estimate, while the NRC-
RES/EPRI report provides additional geometric detail to the ZOI 
estimate.

    Dated: May 9, 2022.

    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. 2022-10323 Filed 5-12-22; 8:45 am]
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