Document: NRC Regulatory Guide
Document ID: cfc61809-5745-460f-8a26-13c168659924
Document Type: regulatory_guide
Title: Identification and Characterization of Seismic Sources and Determination of Safe Shutdown Earthquake Ground Motion
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML0037/ML003740084.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.165
CFR Part: 
CFR Title: 

Content:
of the characteristics of the SSE. 1. With the controlling earthquakes determined as described in Regulatory Position 3 and by using the procedures in Revision 3 of Standard Re view Plan (SRP) Section 2.5.2 (which may in clude the use of ground motion models not in cluded in the PSHA but that are more appropriate for the source, region, and site un der consideration or that represent the latest scientific development), develop 5% of critical damping response spectral shapes for the actual or assumed rock conditions. The same control ling earthquakes are also used to derive vertical response spectral shapes. 2. Use Sa,5-10 to scale the response spectrum shape corresponding to the controlling earthquake. If, as described in Appendix C, there is a control ling earthquake for Sa,1-2.5, determine that the Sa,5-10 scaled response spectrum also envelopes the ground motion spectrum for the controlling earthquake for Sa,1-2.5. Otherwise, modify the shape to envelope the low-frequency spectrum or use two spectra in the following steps. See additional discussion in Appendix F. For a rock site go to Step 4. 3. For nonrock sites, perform a site-specific soil am plification analysis considering uncertainties in site-specific geotechnical properties and parame 65-7 ters to determine response spectra at the free ground surface in the freefield for the actual site conditions. 4. Compare the smooth SSE spectrum or spectra used in design (e.g., 0.3g, broad-band spectra used in advanced light-water reactor designs) with the spectrum or spectra determined in Step 2 for rock sites or determined in Step 3 for the non rock sites to assess the adequacy of the SSE spec trum or spectra. To obtain an adequate design SSE based on the site-specific response spectrum or spectra, develop a smooth spectrum or spectra or use a standard broad band shape that envelopes the spectra of Step 2 or Step 3. Additional discussion of this step is provided in Appendix F. D. IMPLEMENTATION The purpose of this