Document: NUREG-0800
Document ID: e7548e72-8c59-4c82-98dd-ff425e1de29a
Document Type: srp
Title: SEISMIC DESIGN PARAMETERS
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML1235/ML12352A305.pdf
Revision Date: 2023-06
Chapter: 3
Section ID: 3.7.1
CFR Part: 
CFR Title: 

Content:
n developing the OBE and SSE design ground motion needed for the design of nuclear power plant SSCs. The GMRS are site-specific ground spectra determined on the ground surface or as free-field outcrop motions on the uppermost in-situ competent material. The site-specific GMRS at the foundation level in the free-field is referred to as the foundation input response spectra (FIRS). Both the GMRS and the FIRS are defined as free-field outcrop spectra (not including any soil layers above that elevation). Further information on the development of the GMRS and FIRS is described in ISG-01 and ISG-17. The GMRS satisfy the requirements of Title 10 of the Code of Federal Regulations (10 CFR) 100.23 with respect to the development of the SSE. • The site-specific GMRS, reviewed under SRP Section 2.5.2, are determined in the free- field on the ground surface. For sites with soil layers near the surface that will be completely excavated to expose competent material, the GMRS are specified on an outcrop or a hypothetical outcrop that will exist after excavation. Motions at this hypothetical outcrop should be developed as a free surface motion, not as an in-column motion. Competent material is defined as in-situ material having a minimum shear wave velocity of 1,000 feet/second (fps). If non-competent material is present, any excavation and/or backfilling should not alter the development or location of the GMRS. However, the soft soil or backfill material needs to be considered in the soil-structure-interaction (SSI) or other analyses. • In addition, 10 CFR Part 50, Appendix S is applicable to applications for a design certification (DC) or combined license (COL) pursuant to 10 CFR Part 52 or a construction permit (CP) or operating license (OL) pursuant to 10 CFR Part 50 submitted on or after January 10, 1997. Applications subject to this appendix must: $ Demonstrate that the SSE ground motion in the horizontal direction in the free-field at the foundation level of the