Document: NUREG-0800
Document ID: 585516eb-af20-45dc-a470-9638ec9381f3
Document Type: srp
Title: Each calculated spectrum of the artificial time history is considered to envelop
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0706/ML070640306.pdf
Revision Date: 2023-06
Chapter: 3
Section ID: 3.0
CFR Part: 
CFR Title: 

Content:
For the plant subject to Appendix S of 10 CFR Part 50, the horizontal component of the SSE ground motion in the free-field at the foundation level of the structures is based on an appropriate response spectrum with a peak ground acceleration of at least 0.1g. The percentage of critical damping values used in the seismic analysis of Category I SSCs are in conformance with RG 1.61, "Damping Values for Seismic Design of Nuclear Power Plants." The artificial time history used for seismic design of Category I plant SSCs is adjusted in amplitude and frequency content to obtain response spectra that envelop the design response spectra specified for the site and also exhibits sufficient energy in the frequency range of interest. Conformance with the recommendations of Section 2.5.2 and RG 1.61 ensures that the seismic inputs to the analysis of Category I SSCs are adequately defined so as to form a conservative basis for the design of such SSCs to withstand seismic loadings. The CSDRS used in the certified design of seismic Category I SSCs meet the requirements of 10 CFR 100.23 and Appendix S to 10 CFR Part 50 by either: (1) demonstrating that the CSDRS meet or exceed the site-specific GMRS reviewed and approved in the SRP Section 2.5.2 and meet or exceed the minimum required response spectrum specified in 10 CFR Part 50, Appendix S, or (2) by showing that the design resulting from application of the CSDRS is still adequate to resist design demands resulting from the analysis conducted using the site-specific GMRS. The design response spectra used in a non-standard plant for design of seismic Category I SSCs meet the requirements of 10 CFR 100.23 and Appendix S to 10 CFR Part 50, since they meet or exceed the site-specific GMRS reviewed and approved in the SRP Section 2.5.2 and meet or exceed the minimum required response spectrum specified in Appendix S to 10 CFR Part 50. 3.7.1-20 Revision 3 - March 2007 For DC and COL reviews, the findings will also summarize the staff’s