Document: NUREG-0800
Document ID: b757da37-f302-4c36-9b11-c9c186412437
Document Type: srp
Title: Probabilistic Seismic Hazard Analysis and Controlling Earthquakes.  For CEUS
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0707/ML070730593.pdf
Revision Date: 2023-06
Chapter: 2
Section ID: 2.5.2.4
CFR Part: 
CFR Title: 

Content:
at use Regulatory Guide 1.208, three pairs of low and high frequency controlling earthquakes should be determined for the mean 10-4, 10-5, and 10-6 annual probabilities. For applicants that do not use PSHA, the staff will review the method used to derive the controlling earthquakes and, in particular, the methods used to address uncertainties on a case-by-case basis. For sites not in the CEUS, the staff will review the PSHA or other methods in detail. As in the reviews of CEUS sites, the staff will particularly review the approaches used to address uncertainties. The staff will assess the controlling earthquakes for the site derived from the applicant's method to be sure that they adequately represent the local and regional seismic hazard as represented by both historical seismicity and paleoseismicity. The determination of the controlling earthquakes and the seismic hazard information base for sites not in the CEUS is carried out using procedures similar to those used for CEUS. However, because of differences in seismicity rates and ground motion attenuation characteristics at these sites, alternative magnitude-distance parameters may have to be used. In addition, if Regulatory Guide 1.165 is used, an alternative reference probability may also have to be developed, particularly for sites in the active plate margin region and for sites at which a known tectonic structure dominates the hazard. The staff will perform an independent evaluation of the earthquake potential associated with each seismic source that could affect the site. For guidance in evaluating the earthquake potential and characterizing the uncertainty for sites that are assessed using methods other than the LLNL or EPRI methods and data bases, or for sites outside the CEUS, refer to the Senior Seismic Hazard Analysis Committee (SSHAC) Report (Ref. 10). 5.