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:
r the At- Power Operating Mode Element Technical Characteristics and Attributes High Wind Hazard Analysis • Probabilistic wind hazard analysis - results in frequency of high wind at the site - based on site-specific data - reflects recent information • Uncertainties in the models and parameter values - properly accounted for - fully propagated - allow estimate of mean hazard curve High Wind Fragility Analysis • Wind fragility estimate - plant-specific, - realistic - all SSCs whose failure contributes to core damage or large early release included - walkdowns focus on as-built and as-operated plant configuration High Wind Plant Response Analysis • Wind PRA model - includes all significant wind-caused initiating events - includes other significant failures (both those that are wind-caused and those that are random failures) that can lead to CDF or LERF/LRF. - adapted from the internal events, at-power PRA model - incorporates unique wind-analysis aspects that are different from the at- power, internal events PRA model. DG-1362, Page 29 Technical Elements for External Flood, At-Power PRA This section identifies the technical elements for an external flood, at-power PRA. The objective for each technical element is briefly described and the characteristics and attributes needed to achieve the objective are provided in Table 9. The technical elements for an external flood, at-power PRA are: • external flood hazard analysis • external flood fragility analysis • external flood plant response analysis Screening methods can often be employed to show that the contribution of some external flood events to core damage frequency and/or large release frequency is insignificant. The considerations in this section apply to those flood phenomena that have not been screened out. The analysis of how the flood pathways and water levels cause the failure of SSCs following ingress into the plant structures is similar to the analysis in the internal flood PRA. The technical