Document Headings

                    Document headings vary by document type but may contain                    the following:                  
                -                       the agency or agencies that issued and signed a document                    
                -                       the number of the CFR title and the number of each part                      the document amends, proposes to amend, or is directly                      related to                    
                -                       the agency docket number / agency internal file number                    
                -                       the RIN which identifies each regulatory action listed in                      the Unified Agenda of Federal Regulatory and Deregulatory                      Actions                    

                    See the                                          Document Drafting Handbook                                        for more details.                  

###### Nuclear Regulatory Commission

          - 10 CFR Parts 50, 52, and 100
          - [NRC-2023-0097]

# AGENCY:

Nuclear Regulatory Commission.

# ACTION:

Final guide; issuance.

# SUMMARY:

The U.S. Nuclear Regulatory Commission (NRC) is issuing Revision 2 to Regulatory Guide (RG), 1.61, “Damping Values for Seismic Design of Nuclear Power Plants.” This RG provides guidance on damping values that the NRC staff finds acceptable for use in the seismic response analysis of seismic Category I nuclear power plant structures, systems, and components. The specified damping values are intended for elastic dynamic seismic analysis where energy dissipation is accounted for by viscous damping.

# DATES:

Revision 2 to RG 1.61 is available on December 11, 2023.

# ADDRESSES:

Please refer to Docket ID NRC-2023-0097 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:
      -  Federal Rulemaking Website:                          Go to                          https://www.regulations.gov                          and search for Docket ID NRC-2023-0097. Address questions about Docket IDs in                          Regulations.gov                          to Stacy Schumann; telephone: 301-415-0624; email:                          Stacy.Schumann@nrc.gov.                          For technical questions, contact the individuals listed in the                          For Further Information Contact                          section of this document.                    
      -  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                          PDR.Resource@nrc.gov.                          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.                    
      -  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                          PDR.Resource@nrc.gov                          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 2 to RG 1.61 and the regulatory analysis may be found in ADAMS under Accession Nos. ML23284A272 and ML22273A041, respectively.

Regulatory guides are not copyrighted, and NRC approval is not required to reproduce them.

# FOR FURTHER INFORMATION CONTACT:

                        Marcos Rolon Acevedo, Office of Nuclear Regulatory Research, telephone: 301-415-2208; email:                         *Marcos.Rolon@nrc.gov*                         and Edward O'Donnell, Office of Nuclear Regulatory Research, telephone: 301-415-3317; email:                         *Edward.ODonnell@nrc.gov.*                         Both are staff of the U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001.                    

# SUPPLEMENTARY INFORMATION:

## I. Discussion

The NRC is issuing a revision 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.

                    Revision 2 to RG 1.61 was issued with a temporary identification of Draft Regulatory Guide, DG-1364. RG 1.61, Revision 1, specifies the damping values that the NRC staff considers acceptable for complying with the agency's regulations for seismic analysis. This revision of the RG (Revision 2) provides                           ( print page 85825)                        additional guidance related to concrete properties and damping values for use in the development of in structure response spectra. It also includes guidance on damping for steel plate composite walls. In addition, it updates the guidance for piping damping in RG 1.61, Revision 1.                

## II. Additional Information

                    The NRC published a notice of the availability of DG-1364 in the                     **Federal Register**                     on June 13, 2023 (88 FR 38408) for a 30-day public comment period. The public comment period closed on July 13, 2023. Public comments on DG-1364 and the staff responses to the public comments are available under ADAMS under Accession No. ML23284A274.                

                    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 1.61 would not constitute backfitting as that term is defined in section 50.109 of title 10 of the                     *Code of Federal Regulations*                     (10 CFR), “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 an approval issued under 10 CFR part 52, “Licenses, Certifications, and Approvals for Nuclear Power Plants,” as explained in RG 1.61, licensees would not be required to comply with the positions set forth in RG 1.61.                

## 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: December 5, 2023.

For the Nuclear Regulatory Commission.

Stephen M. Wyman,

Acting Chief, Regulatory Guide and Programs Management Branch, Division of Engineering, Office of Nuclear Regulatory Research.

[FR Doc. 2023-27070 Filed 12-8-23; 8:45 am]

BILLING CODE 7590-01-P