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:
) that is characterized by (1) the occurrence of the event in small intervals is constant over time (space), (2) the occur rence of two (or more) events in a small interval is neg ligible, and (3) the occurrence of the event in non-over lapping intervals is independent.. Tectonic Structure - A tectonic structure is a large scale dislocation or distortion, usually within the earth's crust. Its 'extent may be on the order of tens of meters (yards) to hundreds of kilometers (miles). 1.165-11 I I I 1 . APPENDIX B. REFERENCE PROBABILITY FOR THE EXCEEDANCE LEVEL OF THE SAFE SHUTDOWN EARTHQUAKE GROUND MOTION B.1 INTRODUCTION This appendix describes the procedure that is ac ceptable to the NRC staff to determine the reference probability, an annual probability of exceeding the Safe Shutdown Earthquake Ground Motion (SSE), at future nuclear power plant sites. The reference probability is used in Appendix C in conjunction with the probabilis tic seismic hazard analysis (PSHA). B.2 REFERENCE PROBABILITY FOR THE SSE The reference probability is the annual probability level such that 50% of a set of currently operating plants (selected by the NRC, see Table B.1) has an annual mp dian probability of exceeding the SSE that is below this level. The reference probability is determined for the annual probability of exceeding the average of the 5 and 10 Hz SSE response spectrum ordinates associated with 5% of critical damping. B.3 PROCEDURE TO DETERMINE THE REFERENCE PROBABILITY The following procedure was used to determine the reference probability and should be used in the future if general revisions to PSHA methods or data bases result in significant changes in hazard predictions for the se lected plant sites in Table B.I. The reference probability is calculated using the Lawrence Livermore National Laboratory (LLNL) methodology and results (Refs. B.1 and B.2) but is also considered applicable for the Electric Power Research Institute (EPRI) study (Refs. B.3 and B.4). This refer