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:
category, including consideration of timing, location, amount released, and the radionuclide transport barriers and transport mechanisms. • Radiological source terms are calculated using appropriate methods or codes. • Uncertainties in the mechanistic source terms and associated transport phenomena are identified, characterized, and quantified to the extent practical. • Documentation of the mechanistic source term analysis shall provide traceability of the work. C.1.3.17 Radiological Consequence Analysis Probabilistic Risk Assessment Element This section identifies the specific PRA analysis elements, the objectives of those PRA analysis elements, and the characteristics and attributes of the radiological consequence analysis PRA element for an NLWR PRA that addresses all radiological sources, all hazards, all POSs, and all levels of PRA analysis. RG 1.247, Page 45 The objective for each PRA analysis element is briefly described, and the characteristics and attributes needed to achieve the objective are provided below.6 These PRA analysis elements are developed using the assumption that exposure to radionuclides released to the atmosphere is the dominant exposure pathway. These elements do not address exposure due to direct radiation from radiological sources within the facility or exposures due to releases of radioactive material to aqueous pathways such as surface water or ground water. The PRA analysis elements for a radiological consequence analysis are the following: • radionuclide release characterization, • site characterization, • meteorological data analysis, • atmospheric transport and diffusion analysis, • protective action analysis, • dosimetry, • health effects analysis, • economic factors, and • conditional consequence quantification. The objective of the radionuclide release characterization is to identify the attributes of the radionuclide release needed to evaluate radiological consequences. It involves the identification of