Document: NRC Regulatory Guide
Document ID: cde52d5a-adf9-49be-9d1f-59449dfca895
Document Type: regulatory_guide
Title: TRIAL - Acceptability of Probabilistic Risk Assessment Results for Non-Light Water Reactor Risk-Informed Activities
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML2123/ML21235A008.pdf
Revision Date: 2023-05
Chapter: 
Section ID: RG-1.247
CFR Part: 
CFR Title: 

Content:
s intended purpose (e.g., determination of a specific risk metric). The characteristics and attributes of the PRA elements define specific requirements that should be met to successfully perform those technical analyses and achieve a defined objective. Table 1 lists the PRA elements necessary for an acceptable NLWR PRA that addresses all radiological sources, all hazards, all POSs, and all levels of PRA analysis. A PRA that is missing one or more of these elements would not be considered complete. Table 1. PRA Elements • plant operating state analysis • initiating event analysis • event sequence analysis • success criteria development • systems analysis • human reliability analysis • data analysis internal flood PRA • internal fire PRA • seismic PRA • hazard screening PRA • high wind PRA • external flooding PRA • other hazards PRA • event sequence quantification • mechanistic source term analysis • radiological consequence analysis • risk integration These PRA elements are used in the development of an initial PRA model that represents the fundamental plant response to an initiating event, such as equipment or operator failures. A hazard group PRA is developed based on such an initial PRA and also addresses the relationship between the occurrence of a given hazard and the initiating event that starts a given event sequence. For this reason, a hazard group PRA will have some unique analysis requirements that are needed to appropriately represent plant response to a specific hazard in the hazard group. The hazard group-specific PRA analysis elements needed for an acceptable PRA are discussed for each of the hazard group PRA elements. The hazard RG 1.247, Page 19 group-specific PRA analysis elements address the PRA analyses needed specifically for the hazard group under consideration. The risk integration PRA element is an aspect of PRA acceptability that addresses the integration of all risk contributors from all radiological sources,