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:
RA model. The characteristics and attributes needed to achieve the objectives of high wind plant response analysis PRA analysis element are as follows: • All significant high-wind-induced initiating events are included. • Other significant failures (both those that are wind induced and those that are random failures) that can lead to consequence metrics are included. • The high wind PRA systems model is adapted from the internal events PRA model for all modeled POSs and radiological sources. RG 1.247, Page 39 • The model incorporates unique high wind analysis aspects that are different from those in the internal events PRA model. • The uncertainties related to high wind plant response analysis PRA analysis element are identified and characterized. C.1.3.13 External Flooding 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 external flood NLWR PRA that addresses all radiological sources, all POSs, and all levels of PRA analysis. The objective for each technical element is briefly described, and the characteristics and attributes needed to achieve the objective are provided below. It is assumed that the external flood PRA for a POS is based on modifications made to a corresponding up-to-date internal events PRA. The technical elements are evaluated for all POSs and may have different characteristics across POSs. The technical elements for an external flood PRA, applicable to all phases leading up to and including the as-built, as-operated plant, are as follows: • external flood hazard analysis, • external flood fragility analysis, and • external flood plant response analysis. The types of external flood phenomena that should be considered in the analysis are dependent on the site. Both natural phenomena, such as river or lake flooding, ocean flooding from high tides or storm