Document: NRC Regulatory Guide
Document ID: 22ccfd5e-c5d8-4615-a02c-32369aa9f533
Document Type: regulatory_guide
Title: Acceptability of Probabilistic Risk Assessment Results for Risk-Informed Activities (Rev. 3)
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML1930/ML19308B636.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.200
CFR Part: 
CFR Title: 

Content:
C failures, as well as significant non-seismic failures and human errors. The model reflects the as-built and as-operated plant. In meeting the technical characteristics and attributes for the seismic portion of an external hazard PRA, a seismic margins method is not an acceptable approach to the NRC staff because a seismic margins method does not define and quantify seismically-induced accident sequences. A seismic PRA developed by COL holders such that it meets the requirements of (a) ASME/ANS RA-Sa-2009 Part 5, as endorsed in Appendix A of this regulatory guide, or (b) ASME/ANS RA-S Case 1, as endorsed in Appendix B of this regulatory guide are acceptable ways to meet the seismic hazard portion of the fuel-load PRA requirements per 10 CFR 50.71(h)(1). Table 6. Summary of Technical Characteristics and Attributes of a Seismic PRA for the At- Power Operating Mode Element Technical Characteristics and Attributes Probabilistic Seismic Analysis • Seismic hazard analysis - establishes the frequency of earthquakes at the site - site-specific - examines all credible sources of damaging earthquakes - includes current information - based on comprehensive data, including - geological, seismological, and geophysical data - local site topography - historical information - reflects the composite distribution of the informed technical community. - level of analysis depends on application and site complexity • Aleatory and epistemic uncertainties in the hazard analysis (in characterizing the seismic sources and the ground motion propagation) - properly accounted for - fully propagated - allow estimates of - fractile hazard curves, - median and mean hazard curves, - uniform hazard response spectra • Spectral shape used in the seismic PRA - based on a site-specific evaluation DG-1362, Page 26 Table 6. Summary of Technical Characteristics and Attributes of a Seismic PRA for the At- Power Operating Mode Element Technical Characteristics and Attributes - broad-band, smooth