Document: NRC Regulatory Guide
Document ID: aa62c83d-b03d-4406-b6eb-31fc79a0c077
Document Type: regulatory_guide
Title: Development of Floor Design Response Spectra for Seismic Design of Floor-Supported Equipment or Components + HISTORY – HISTORY 05/2019 – Periodic Review of Revision 1 – Reviewed with issues considered for future consideration 03/2015 – Periodic Review of Revision 1 – Revise
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML1404/ML14041a433.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.122
CFR Part: 
CFR Title: 

Content:
Regulatory Guide Periodic Review Regulatory Guide Number: 1.122 Revision: 1 Title: Development of Floor Response Spectra for Seismic Design of Floor Supported Equipment or Components Office/division/branch: RES/DE/SGSEB Technical Lead: Scott Stovall Staff Action Decided: Revise 1. What are the known technical or regulatory issues with the current version of the Regulatory Guide (RG)? The RG dates to 1978 and is written at a very high level. The methodology is based on techniques in use at that time. There are no details on acceptable methods for the incorporation of uncertainties in material properties of the structure and soil, damping values, and soil-structure interaction models in the current version of the RG. Since its issuance there has been significant progress with probabilistic methods and this information should be incorporated into future revisions of the guide. The staff recognizes that the development of fully probabilistic floor spectra is not practical in the very-short term. However, hazard-informed floor spectra are needed for use in seismic probabilistic risk analyses (SPRA). In its current form the RG provides no guidance on how to develop consistent hazard-informed floor spectra. Material to be considered in updating the guide includes: • American Society of Civil Engineers (ASCE) 4-98, “Seismic Analysis of Safety- Related Nuclear Structures and Commentary,” (1998); • ASCE 43-05, “Seismic Design Criteria for Structures, Systems, and Components in Nuclear Facilities,” (2005); • ASME/ANS RA-S, Standard for Level 1/Large Early Release Frequency Probabilistic Risk Assessment for Nuclear Power Plant Applications; • Electric Power & Research Institute (EPRI) “Seismic Evaluation Guidance,” EPRI Report 1025287, (2010), ADAMS accession number ML12333A170; • Interim Staff Guidance DC/COL ISG-020, “Interim Staff Guidance on Implementation of a Probabilistic Risk Assessment-Based Seismic Margin Analysis for New Reactors,” (2010),