[Federal Register Volume 88, Number 160 (Monday, August 21, 2023)]
[Rules and Regulations]
[Pages 56750-56752]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2023-17908]


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NUCLEAR REGULATORY COMMISSION

10 CFR Parts 50, 52 and 100

[NRC-2021-0133]


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

AGENCY: Nuclear Regulatory Commission.

ACTION: Final guide; issuance.

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SUMMARY: The U.S. Nuclear Regulatory Commission (NRC) is issuing a new 
Regulatory Guide (RG) 1.249 (Revision 0), ``Use of ARCON Methodology 
for Calculation of Accident-Related Offsite Atmospheric Dispersion 
Factors.'' This new 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

[[Page 56751]]

boundaries from a design-basis accident. Also, this RG 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: Revision 0 to RG 1.249 is available on August 21, 2023.

ADDRESSES: Please refer to Docket ID NRC-2021-0133 when contacting the 
NRC about the availability of information regarding this document. You 
may obtain publicly available information related to this document 
using any of the following methods:
    <bullet> Federal Rulemaking website: Go to https://www.regulations.gov and search for Docket ID NRC-2021-0133. Address 
questions about Dockets IDs in Regulations.gov to Stacy Schumann; 
telephone: 301-415-0624; email: <a href="/cdn-cgi/l/email-protection#91c2e5f0f2e8bfc2f2f9e4fcf0ffffd1ffe3f2bff6fee7"><span class="__cf_email__" data-cfemail="b4e7c0d5d7cd9ae7d7dcc1d9d5dadaf4dac6d79ad3dbc2">[email protected]</span></a>. For technical 
questions, contact the individuals 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 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, at 301-415-4737, 
or by email to <a href="/cdn-cgi/l/email-protection#92c2d6c0bcc0f7e1fde7e0f1f7d2fce0f1bcf5fde4"><span class="__cf_email__" data-cfemail="2a7a6e7804784f59455f58494f6a445849044d455c">[email protected]</span></a>.
    <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#adfde9ff83ffc8dec2d8dfcec8edc3dfce83cac2db"><span class="__cf_email__" data-cfemail="376773651965524458424554527759455419505841">[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.
    Revision 0 to RG 1.249 and the regulatory analysis may be found in 
ADAMS under Accession Nos. ML22024A241 and ML21165A007, respectively.
    Regulatory guides are not copyrighted, and NRC approval is not 
required to reproduce them.

FOR FURTHER INFORMATION CONTACT: Kevin Quinlan, Office of Nuclear 
Reactor Regulation, telephone: 301-415-6809, email: 
<a href="/cdn-cgi/l/email-protection#622907140b0c4c33170b0c0e030c220c10014c050d14"><span class="__cf_email__" data-cfemail="511a3427383f7f0024383f3d303f113f23327f363e27">[email protected]</span></a>, or Jason White, Office of Nuclear Reactor 
Regulation, telephone: 301-415-3212, email: <a href="/cdn-cgi/l/email-protection#88c2e9fbe7e6a6dfe0e1fcedc8e6faeba6efe7fe"><span class="__cf_email__" data-cfemail="a3e9c2d0cccd8df4cbcad7c6e3cdd1c08dc4ccd5">[email protected]</span></a>, or 
Harriet Karagiannis, Office of Nuclear Regulatory Research, telephone: 
301-415-2493, email: <a href="/cdn-cgi/l/email-protection#d890b9aaaab1bdacf693b9aab9bfb1b9b6b6b1ab98b6aabbf6bfb7ae"><span class="__cf_email__" data-cfemail="0e466f7c7c676b7a20456f7c6f69676f6060677d4e607c6d20696178">[email protected]</span></a>. All are staff of the 
U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001.

SUPPLEMENTARY INFORMATION: 

I. Discussion

    The NRC is issuing a new guide 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.
    For clarification, Revision 0 of RG 1.249 was issued for public 
comment with a temporary identification of draft Regulatory Guide (DG), 
DG-4030, to RG 4.28, titled, ``Use of ARCON Methodology for Calculation 
of Accident-Related Offsite Atmospheric Dispersion Factors.'' After 
further consideration of the applicability of this RG, the staff 
decided that it is more suitable to be listed under the RGs of Division 
1, titled, ``Power Reactors.'' As a result, the RG number was changed 
to RG 1.249 using the same RG title, instead of being listed under 
Division 4, titled, ``Environmental and Siting,'' as RG 4.28. The 
content of the RG did not change due to it being issued under Division 
1 instead of Division 4.

II. Additional Information

    The NRC published a notice of the availability of DG-4030 (ADAMS 
Accession No. ML21165A005), in the Federal Register on August 17, 2021 
(86 FR 46024), for a 30-day public comment period. The public comment 
period closed on September 16, 2021. The staff received 5 comment 
submissions and a total of 30 public comments. Public comments on DG-
4030 and the staff responses to the public comments are available in 
ADAMS under Accession No. ML22024A245.
    This new RG 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 (3937 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 (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), Standard Review Plan (SRP) Section 2.3.4 for calculating 
accident-related related, offsite atmospheric dispersion values.
    RG 1.249 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.''
    As noted in the Federal Register on December 9, 2022 (87 FR 75671), 
this document is being published in the ``Rules'' section of the 
Federal Register to comply with publication requirements under 1 CFR 
chapter I.

III. Congressional Review Act

    This RG is 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 it to be a major rule as defined in the Congressional Review Act.

IV. Backfitting, Forward Fitting, and Issue Finality

    Issuance of RG 1.249, Revision 0, does 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'' (ADAMS Accession No. ML18093B087); 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 RG 1.249, applicants and licensees are not required to 
comply with the positions set forth in this regulatory guide.

V. Submitting Suggestions for Improvement of Regulatory Guides

    A member of the public may, at any time, submit suggestions to the 
NRC for improvement of existing RGs or for the development of new RGs. 
Suggestions can be submitted on the NRC's public website at https://www.nrc.gov/reading-rm/doc-collections/reg-guides/contactus.html. 
Suggestions will be considered in future updates and enhancements to 
the ``Regulatory Guide'' series.

    Dated: August 16, 2023.


[[Page 56752]]


    For the Nuclear Regulatory Commission.
Michael A. Eudy,
Acting Chief, Regulatory Guide and Programs Management Branch, Division 
of Engineering, Office of Nuclear Regulatory Research.
[FR Doc. 2023-17908 Filed 8-18-23; 8:45 am]
BILLING CODE 7590-01-P


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