[Federal Register Volume 84, Number 57 (Monday, March 25, 2019)]
[Notices]
[Pages 11136-11137]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2019-05606]
[[Page 11136]]
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NUCLEAR REGULATORY COMMISSION
[NRC-2019-0043]
Credibility Assessment Framework for Critical Boiling Transition
Models
AGENCY: Nuclear Regulatory Commission.
ACTION: Draft NUREG; request for comment.
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SUMMARY: The U.S. Nuclear Regulatory Commission (NRC) is issuing for
public comment a draft NUREG (U.S. Nuclear Regulatory Commission
technical report designation), knowledge management NUREG (NUREG/KM) -
0013, ``Credibility Assessment Framework for Critical Boiling
Transition Models.'' This NUREG describes NRC past practice and staff
experience in determining the credibility of critical heat flux and
critical power models and, based on that experience, presents an
assessment framework that combines aspects of goal structuring notation
and maturity assessment.
DATES: Submit comments by May 24, 2019. 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 before this
date.
ADDRESSES: Please refer to Docket ID NRC-2019-0043 when contacting the
NRC about the availability of information regarding this document. You
may submit comments by any of the following methods:
Federal Rulemaking Website: Go to http://www.regulations.gov and search for Docket ID NRC-2019-0043. Address
questions about NRC dockets IDs in Regulations.gov to Jennifer Borges;
telephone: 301-287-9127; 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: Joshua Kaizer, Office of Nuclear
Reactor Regulation, U.S. Nuclear Regulatory Commission, Washington, DC
20555-0001; telephone: 301-415-1532, email: [email protected].
SUPPLEMENTARY INFORMATION:
I. Obtaining Information and Submitting Comments
A. Obtaining Information
Please refer to Docket ID NRC-2019-0043 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 http://www.regulations.gov and search for Docket ID NRC-2019-0043.
NRC's Agencywide Documents Access and Management System
(ADAMS): You may obtain publicly available documents online in the
ADAMS Public Document collection at https://www.nrc.gov/reading-rm/adams.html. To begin the search, select ``Begin Web-based ADAMS
Search.'' For problems with ADAMS, 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 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. Draft NUREG/KM-0013 is available
in ADAMS under Accession No. ML19073A249.
NRC's PDR: You may examine and purchase copies of public
documents at the NRC's PDR, Room O1-F21, One White Flint North, 11555
Rockville Pike, Rockville, Maryland 20852.
B. Submitting Comments
Please include Docket ID NRC-2019-0043 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 http://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
Critical boiling transition (CBT) occurs when a flow regime that
has a higher heat transfer rate transitions to a flow regime that has a
significantly lower heat transfer rate. Models that predict a CBT are a
necessary part of reactor safety analysis because they are used to
determine plant safety limits. Therefore, the review of CBT models has
been a focus of the NRC since its inception in 1975.
Draft NUREG/KM-0013 describes NRC practice and staff experience in
evaluating CBT models and organizes that practice and staff experience
in the form of a credibility assessment framework that combines aspects
of goal structure notation and maturity assessment. The NRC has
performed many such assessments in the past and has generated this
framework based on the experience of the current NRC staff and previous
reviews performed by the staff as summarized in its evaluations. This
document includes a survey of the important technical and regulatory
literature; a detailed technical discussion of CBT models and their
application; and a framework for CBT models that reflects NRC practice
as a whole, including the level of evidence previously accepted to
address the various issues relevant to the evaluation of CBT models.
Accordingly, the NRC is requesting comments on the NUREG-0013/KM
description of the NRC practice and experience in evaluating CBT models
and the adequacy of the assessment framework presented.
The framework presented in NUREG-0013/KM is intended as a
``textbook'' reference for those interested in the assessment of the
credibility of CBT models, particularly as applied to reactor safety
analysis. Nonetheless, Draft NUREG-0013/KM is not guidance to the NRC
staff, applicants for NRC licenses, or current NRC licensees, and, if
finalized, would not constitute backfitting, as defined in title 10 of
the Code of Federal Regulations (10 CFR) 50.109 (the Backfit Rule), or
otherwise be inconsistent with the issue finality provisions in 10 CFR
part 52. In the future, the NRC staff may decide to reference NUREG-
0013/KM in guidance to the NRC staff or guidance to applicants or
licensees, i.e., through an update to the Standard Review Plan or new
Interim Staff Guidance, or update to a Regulatory Guide, respectively.
Should the NRC staff decide to do so, the NRC staff will seek public
comment on the use of NUREG-0013/KM as guidance and will assess any 10
CFR 50.109 backfitting and part 52 issue
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finality considerations arising from such use.
Dated at Rockville, Maryland, this 20th day of March 2019.
For the Nuclear Regulatory Commission.
Robert G. Lukes,
Chief, Nuclear Performance and Code Review, Division of Safety Systems,
Office of Nuclear Reactor Regulation.
[FR Doc. 2019-05606 Filed 3-22-19; 8:45 am]
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