[Federal Register Volume 86, Number 156 (Tuesday, August 17, 2021)]
[Notices]
[Pages 46024-46025]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2021-17596]


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NUCLEAR REGULATORY COMMISSION

[NRC-2021-0133]


Use of ARCON Methodology for Calculation of Accident-Related 
Offsite Atmospheric Dispersion Factors

AGENCY: Nuclear Regulatory Commission.

ACTION: Draft regulatory guide; request for comment.

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SUMMARY: The U.S. Nuclear Regulatory Commission (NRC) is issuing for 
public comment draft regulatory guide (DG), DG-4030, ``Use of ARCON 
Methodology for Calculation of Accident-Related Offsite Atmospheric 
Dispersion Factors.'' This proposed new regulatory guide (RG) describes 
an approach for reactor applicants and licensees for determining 
atmospheric relative concentration ([chi]/Q) values in support of 
modeling onsite releases to offsite boundaries from a design-basis 
accident. Also, this proposed guidance implements the methodology in RG 
1.194, ``Atmospheric Relative Concentrations for Control Room 
Radiological Habitability Assessments at Nuclear Power Plants,'' for 
offsite dose locations at boundaries.

DATES: Submit comments by September 16, 2021. Comments received after 
this date will be considered if it is practical to do so, but the NRC 
is able to ensure consideration only for comments received on or before 
this date. Although a time limit is given, comments and suggestions in 
connection with items for inclusion in guides currently being developed 
or improvements in all published guides are encouraged at any time.

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-2021-0133. Address 
questions about Docket IDs in Regulations.gov to Stacy Schumann; 
telephone: 301-415-0624; email: [email protected]. For technical 
questions, contact the individuals 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 accessing information and submitting 
comments, see ``Obtaining Information and Submitting Comments'' in the 
SUPPLEMENTARY INFORMATION section of this document.

FOR FURTHER INFORMATION CONTACT: Jason White, Office of Nuclear Reactor 
Regulation, telephone: 301-415-3212, email: [email protected], Kevin 
Quinlan, Office of Nuclear Reactor Regulation, telephone: 301-415-6809, 
email: [email protected], or Harriet Karagiannis, Office of Nuclear 
Regulatory Research, telephone: 301-415-2493, email: 
[email protected]. All are staff of the U.S. Nuclear 
Regulatory Commission, Washington, DC 20555-0001.

SUPPLEMENTARY INFORMATION:

I. Obtaining Information and Submitting Comments

A. Obtaining Information

    Please refer to Docket ID NRC-2021-0133 when contacting the NRC 
about the availability of information regarding 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-2021-0133.
     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].
     Attention: The PDR, where you may examine, and order 
copies of public documents, is currently closed. You may submit your 
request to the PDR via email at [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-2021-0133 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

[[Page 46025]]

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 submissions into ADAMS.

II. Additional Information

    The NRC is issuing for public comment a DG 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 needs in its review of applications 
for permits and licenses.
    This DG, identified by its task number, DG-4030, titled, ``Use of 
ARCON Methodology for Calculation of Accident-Related Offsite 
Atmospheric Dispersion Factors,'' is a proposed new RG 4.28 (ADAMS 
Accession No. ML21165A005). This proposed new RG 4.28 provides guidance 
to industry for complying with and implementing the NRC requirements by 
endorsing the use of the ARCON computer code to calculate offsite 
dispersion values out to distances of 1,200 m (3,937 ft) that could 
include the exclusion area boundary and/or low-population zone.
    RG 1.194 (ADAMS Accession No. ML031530505) endorses the use of the 
ARCON96 computer code for calculating accident-related onsite (control 
room and technical support center) atmospheric dispersion values which 
are direct inputs to habitability dose assessments. In addition, RG 
1.145, ``Atmospheric Dispersion Models for Potential Accident 
Consequence Assessments at Nuclear Power Plants'' (ADAMS Accession No. 
ML12216A014), provides the present methodology incorporated into the 
PAVAN computer code, as reviewed by the staff using NUREG-0800 at 
https://www.nrc.gov/reading-rm/doc-collections/nuregs/staff/sr0800/index.html (ADAMS Accession No. ML070810350), SRP Section 2.3.4 for 
calculating accident-related related, offsite atmospheric dispersion 
values.
    RG 4.28 will provide new guidance for applicants and licensees 
subject to Part 50 of title 10 of the Code of Federal Regulations (10 
CFR), ``Domestic Licensing of Production and Utilization Facilities''; 
10 CFR part 52, ``Licenses, Certifications, and Approvals for Nuclear 
Power Plants''; and 10 CFR part 100, ``Reactor site criteria.''
    The staff is also issuing for public comment a draft regulatory 
analysis (ADAMS Accession No. ML21165A007). The staff develops a 
regulatory analysis to assess the value of issuing or revising a 
regulatory guide as well as alternative courses of action.

III. Backfitting, Forward Fitting, and Issue Finality

    Issuance of DG-4030, if finalized, would not 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''; constitute forward fitting as that term is defined and 
described in MD 8.4; or affect issue finality of any approval issued 
under 10 CFR part 52. As explained in DG-4030, applicants and licensees 
are not required to comply with the positions set forth in DG-4030.

    Dated: August 10, 2021.

    For the Nuclear Regulatory Commission.
Ronaldo V. Jenkins,
Acting Chief, Regulatory Guidance and Programs Management Branch, 
Division of Engineering, Office of Nuclear Regulatory Research.
[FR Doc. 2021-17596 Filed 8-16-21; 8:45 am]
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