Daily Rules, Proposed Rules, and Notices of the Federal Government



Combining Modal Responses and Spatial Components in Seismic Response Analysis

AGENCY: Nuclear Regulatory Commission.
ACTION: Regulatory guide; issuance.
SUMMARY: The U.S. Nuclear Regulatory Commission (NRC) is issuing Revision 3 to Regulatory Guide (RG) 1.92, "Combining Modal Responses and Spatial Components in Seismic Response Analysis" as an administratively changed guide in which there are minor corrections with no substantive changes in the Staff Regulatory Guidance. This guide describes a method that the NRC staff considers acceptable for combining modal responses and spatial components in seismic response analysis of nuclear power plant structures, systems, and components that are important to safety.
ADDRESSES: *Federal Rulemaking Web site: Go tohttp://www.regulations.govand search for Docket ID NRC-2012-0223. Address questions about NRC dockets to Carol Gallagher; telephone: 301-492-3668;

*NRC's Agencywide Documents Access and Management System (ADAMS): You may access publicly available documents online in the NRC Library at begin the search, select "ADAMS Public Documents" and then 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 3 of Regulatory Guide 1.92 is available in ADAMS under Accession No. ML12220A043. The regulatory analysis may be found in ADAMS under Accession No. ML122020A044.

*NRC's Public Document Room: You may examine and purchase copies of public documents at the NRC's Public Document Room O1-F21, One White Flint North, 11555 Rockville Pike, Rockville, Maryland 20852.

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

FOR FURTHER INFORMATION CONTACT: Edward O'Donnell, Office of Nuclear Regulatory Research, U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, telephone: 301-251-7455;

The NRC is issuing an administrative to an existing guide in the NRC's “Regulatory Guide” series. The Regulatory Guides were developed to describe and make available to the public information methods that are acceptable to the NRC staff for implementing specific parts of the agency's regulations, techniques that the staff uses in evaluating specific problems or postulated accidents, and data that the staff needs in its review of applications for permits and licenses. The NRC typically seeks public comment on a draft version of a regulatory guide by announcing its availability for comment in theFederal Register. However, as explained on page 7 of NRC Management Directive 6.6 “Regulatory Guides,” (ADAMS Accession Number ML110330475) the NRC may directly issue a final regulatory guide without a draft version or public comment period if the changes to the regulatory guide are non-substantive, including changes to the Staff Regulatory Guidance section. Issuance of regulatory guides using this direct final process reduces processing time and review costs. A regulatory guide revised using this process is called an Administratively Changed Guide (ACG).

II. Submitting Comments

Although Revision 3 of RG 1.92 is being issued as an administratively changed guide without public comment, comments are welcome on any final regulatory guide at any time. The input from the public and stakeholders will be considered in future updates and enhancements of the regulatory guide. Comments can be submitted by the form available online at

III. Further Information

The NRC is issuing Revision 3 of RG 1.92 directly as a final regulatory guide because the changes between Revision 2 and Revision 3 are non-substantive. The current revision was published in 2006. In the course of a periodic review of the guide, the staff noted that some minor corrections were needed that would result in no substantive change in the Staff Regulatory Guidance. Among the corrections are the addition of missing ADAMS accession numbers for some of the references, and insertion of the language currently used for the Implementation Section. That section was revised subsequent to issuance of Revision 2 in 2006 to clarify that compliance with the Regulatory Guide is voluntary and that the NRC staff does not intend any backfitting of the guidance.

IV. Backfitting and Issue Finality

Issuance of this final regulatory guide does not constitute backfitting as defined in § 50.109 of Title 10 of theCode of Federal Regulations(10 CFR) (the Backfit Rule) and is not otherwise inconsistent with the issue finality provisions in 10 CFR part 52. As discussed in the “Implementation” section of this regulatory guide, the NRC has no current intention to impose this regulatory guide on holders of current operating licenses or combined licenses.

This regulatory guide may be applied to applications for operating licenses and combined licenses docketed by the NRC as of the date of issuance of the final regulatory guide, as well as future applications for operating licenses and combined licenses submitted after the issuance of the regulatory guide. Such action does not constitute backfitting as defined in 10 CFR 50.109(a)(1) and is not otherwise inconsistent with the applicable issue finality provision in 10 CFR part 52, inasmuch as such applicants or potential applicants are not within the scope of entities protected by the Backfit Rule or the relevant issue finality provisions in 10 CFR part 52.

Dated at Rockville, Maryland, this 7th day of November 2012.

For the Nuclear Regulatory Commission.

Thomas H. Boyce, Chief, Regulatory Guide Development Branch, Division of Engineering, Office of Nuclear Regulatory Research.