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:
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 elements, the objectives of those analysis elements, and the characteristics and attributes that are needed for an acceptable high wind NLWR PRA that addresses all radiological sources, all POSs, and all levels of PRA analysis. The objective of each high wind PRA analysis element is briefly described, and the characteristics and attributes needed to achieve the objective are provided below. The high wind PRA analysis elements for all POSs are as follows: • high wind hazards analysis, • high wind fragility analysis, and • high wind plant response analysis. The types of high wind events that should be considered in the analysis are site dependent. They can include tornadoes, tropical cyclones (i.e., hurricanes, typhoons), thunderstorms, squall lines, and other weather fronts that produce high winds. It is assumed that the high wind PRA is based on modifications made to an existing, up-to-date, internal events, at-power PRA. The technical elements for a high wind PRA are similar to those for a seismic PRA. Because of its dependence on the internal events model, the high wind PRA incorporates the elements of Regulatory Positions C.1.3.1 through C.1.3.7 of this RG, as necessary. The objective of a high wind hazard analysis is to estimate the frequency of high wind at the site using a site-specific probabilistic wind hazard analysis that incorporates the available recent regional RG 1.247, Page 38 and site-specific information and up-to-date databases. Uncertainties in the models and parameter values are properly accounted for and fully propagated to allow the derivation of a mean hazard curve from the family of hazard curves obtained. The characteristics and attributes needed to achieve the objectives of the high wind hazard analysis PRA analysis element are as