Document: NRC Regulatory Guide
Document ID: 8a2332d3-66ca-40af-84e1-507db8b26559
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:
ately characterized. • The deposition of airborne material on the ground by wet and dry deposition and the resulting depletion of the airborne material with downwind distance are modeled in a manner that is appropriate for the application. • The uncertainties related to the atmospheric transport and diffusion analysis are identified and characterized. The objective of the protective action analysis is to characterize the impact of mitigation measures such as evacuation, sheltering, relocation, and interdiction of land, food, or water on doses resulting from releases of radioisotopes. The variability in the responses of offsite populations to releases of radioisotopes may be considered. For PRAs performed prior to selecting a proposed site, protective actions are addressed with postulated data that contain sufficient information to allow comparison of the postulated protective action data to protective actions for a selected site. The characteristics and attributes needed to achieve the objectives of the protective action analysis PRA analysis element are as follows: • Protective actions that are appropriate for the application are identified and included. • The analysis is based on recognized sources of protective action guidance such as approved emergency plans and Federal, State, or local guidance. Justification of the sources of protective action guidance used in the analysis is provided when multiple recognized sources recommend different values (e.g., local requirements are more stringent than national requirements, use of international standards in lieu of U.S. standards). • The analysis of early-phase protective actions includes site-specific consideration of the time at which warning of a release is provided to offsite populations, the delays before the offsite populations either shelter or evacuate, or both, and the speed at which evacuation proceeds. The consideration of these factors is based on recognized site-specific sources such as