Document: NUREG-0800
Document ID: 91dd5605-fced-4aa9-82f4-b0def4175216
Document Type: srp
Title: Safe Shutdown Earthquake. In meeting the requirements of Ref-
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0523/ML052340591.pdf
Revision Date: 2023-06
Chapter: 2
Section ID: 2.5.2.6
CFR Part: 
CFR Title: 

Content:
he input parameters and the appropriateness of the model are thoroughly docu- mented (e.g., Refs. 19, 44, 45 and 46). Modeling is particul arly useful for sites near capable faults that may experience ground motion that is different in terms of frequency content and wave type from ground motion caused by more distant earthquakes. 5. Probabilistic estimates of seismic hazard should be calculated (e.g., Refs. 41 and 47) and the underlying assumptions and associated uncer- tainties should be documented to assist in the staff's overall deter- ministic approach. The probabilistic studies should highlight which seismic sources are significant to the site. Uniform hazard spectra (spectra that have a uniform probability of exceedance over the fre- quency range of interest) showing uncertainty should be calculated for 0.01, 0.001, and 0.0001 annual probabilities of exceedance at the site. The probability of exceeding the SSE response spectra should also be estimated and comparison of results made with other probabilistic studies. The time duration and number of cycles of strong ground motion is required for analysis of site foundation liquefaction potential and for design of many plant components. The adequacy of the time history for structural analysis is reviewed under SRP Section 3.7.1. The time history is reviewed in this SRP section to confirm that it is compatible with the seismological and geological conditions in the site vicinity and with the accepted SSE model. At present, models for deterministically computing the time history of strong ground motion from a given source-site configuration may be limited. It is therefore acceptable to use an ensemble of ground-motion time histories from earthquakes with similar size, site-source characteristics, and spectral characteristics or results of a statistical analysis of such an ensemble. Total duration of the motion is acceptable when it is as conservative as values determined using current studies such as References 48,