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Seismic Design Classification for Nuclear Power Plants

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Nuclear Regulatory Commission.


Regulatory guide; issuance.


The U.S. Nuclear Regulatory Commission (NRC) is issuing Revision 6 to Regulatory Guide (RG) 1.29, “Seismic Design Classification for Nuclear Power Plants.” This RG describes a method that the staff of the NRC considers acceptable for use in identifying and classifying those features of light-water-reactor nuclear power plants that must be designed to withstand the effects of the safe-shutdown earthquake. Revision 6 corrects a minor error in the numbering of the elements in Section C, “Staff Regulatory Guidance.”


RG 1.29 is available on August 2, 2021.


Please refer to Docket ID NRC-2015-0220 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 and search for Docket ID NRC-2015-0220. Address questions about Docket IDs in to Stacy Schumann; telephone: 301-415-0624; email: 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​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 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.
  • 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 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.

Revision 6 to RG 1.29 and the regulatory analysis may be found in ADAMS under Accession Nos. ML21155A003 and ML21155A004, respectively.

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

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Yuken Wong, Office of Nuclear Reactor Regulation, telephone: 301-415-0500, email: and Edward O'Donnell, Office of Nuclear Regulatory Research, telephone: 301-415-3317, email: Both are staff of the U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001.

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I. Discussion

The NRC is issuing a revision to an existing guide in the NRC's “Regulatory Guide” series. This series was developed to describe and make available to the public information regarding methods that are acceptable to the NRC staff for implementing specific parts of the agency's regulations, techniques that the NRC staff uses in evaluating specific issues or postulated events, and data that the NRC staff needs in its review of applications for permits and licenses.

II. Additional Information

RG 1.29, Revision 6 corrects a minor error in the numbering within the Section C, “Staff Regulatory Guidance.” What was C.1.i became C.2. This results in C.2 becoming C.3 and C.3 became C.4. In addition, RG 1.29 was reformatted to conform with the current template for Regulatory Guides.

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 and Issue Finality

Issuance of RG 1.29 does not constitute backfitting as 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”; 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, “Licenses, Certificates, and Approvals for Nuclear Power Plants.” As explained in this regulatory guide, applicants and licensees would not be required to comply with the positions set forth in this RG.

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Dated: July 27, 2021.

For the Nuclear Regulatory Commission.

Meraj Rahimi,

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

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[FR Doc. 2021-16343 Filed 7-30-21; 8:45 am]