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:
bins greater than distances of 100 km as discussed in Step 4 and deter mined according to: 1.165-18 I-. P(M, d)2 Ln {D,(1 - 2.5 Hz)} = Ln(d) P > 100(m,d), d>10 ., Equation (7) where d is the centroid distance value for each dis tance bin. Step 8 Determine the SSE response spectrum using the procedure described in Appendix F of this regulatory guide. C.3 EXAMPLE FOR A CEUS SITE To illustrate the procedure in Section C.2, calcula tions are shown here for a CEUS site using the 1993 LLNL hazard results (Refs. C.1 and C.2). It must be emphasized that the recommended magnitude and dis tance bins and procedure used to establish controlling earthquakes were developed for application in the CEUS where the nearby earthquakes generally control the response in the 5 to 10 Hz frequency range, and larg er but distant events can control the lower frequency range. For other situations, alternative binning schemes as well as a study of contributions from various bins will be necessary to identify controlling earthquakes consistent with the distribution of the seismicity. Step 1 The 1993 LLNL seismic hazard methodology (Refs. C.1 and C.2) was used to determine the hazard at the site. A lower bound magnitude of 5.0 was used in this analysis. The analysis was performed for spectral acceleration at 1, 2.5, 5, and 10Hz. The resultant hazard curves are plotted in Figure C.1. Step 2 The hazard curves at 1, 2.5, 5, and 10 Hz obtained in Step I are assessed at the reference probability value of 1E-5/yr, as defined in Appendix B to this regulatory guide. The corresponding ground motion level values are given in Table C.2. See Figure C.1. The average of the ground motion levels at the 1 and 2.5 Hz, Sa1-2.5, and 5 and 10 Hz, Sa5-10, are given in Table C.3. Step 3 The median seismic hazard is de-aggregated for the matrix of magnitude and distance bins as given in Table C.1. A complete probabilistic hazard analysis was per formed for each bin to determine the contribution to the hazard from all