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:
G 1.247, Page 37 excluded from further analysis in the PRA. Preliminary screening analyses generally involve more simple and less involved analysis (e.g., demonstrating a hazard or hazard group is not physically realizable at a site or range of sites). Detailed screening analyses may be performed to demonstrate that pre-defined quantitative screening criteria are met and the hazard or hazard group under consideration can be excluded from further analysis in the PRA. Detailed screening analyses should be performed using a bounding or demonstrably conservative analysis to develop a quantitative estimate of risk. Walkdowns of the plant site and plant buildings or the evaluation of available data and findings of investigations of the plant design and operations information are used to confirm assumptions that help form the basis for screening. For some applications, the staff may need to examine and confirm the validity of the assumptions used to screen out a hazard from the PRA by using application-specific guidance. The characteristics and attributes needed to achieve the objectives of a hazards screening analysis are as follows: • All potential hazards that can affect the design, plant, or site or that are unique to a specific design, plant, or site are systematically identified. • A preliminary screening is performed using predefined qualitative screening criteria. • A detailed screening analysis is performed using predefined quantitative screening criteria and should involve bounding or conservative analyses. • The basis for any screening analysis is confirmed with a walkdown for plants with a selected site or by evaluating available data and findings of investigations of the plant design and operations information for plants without a selected site. • The uncertainties related to hazard screening are identified and characterized. C.1.3.12 High Wind Probabilistic Risk Assessment Element This section identifies the hazard group-specific PRA analysis