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:
on. 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 release categories and the development of source term information for each release category. Release category information includes the selection of a representative radiological source term for each release category (as discussed in Regulatory Position C.1.3.16 on mechanistic source term analysis). Source term information, developed as discussed in Regulatory Position C.1.3.16, includes an identification of risk- significant isotopes to be included in the consequence assessment and data needed to characterize release locations, the physical/chemical form of the released radioisotopes, the time--dependent isotopic release rates to the atmosphere, and the data needed to estimate plume rise due to buoyancy, momentum, or both. The characteristics and attributes needed to achieve the objectives of the radionuclide release characterization PRA analysis element are as follows: • Release categories are defined using acceptable methods (see Regulatory Position C.1.3.16). • All risk-significant isotopes are included in the radiological consequence analysis. • Radiological source terms contain information on release locations, the physical/chemical form of the released isotopes, the time-dependent isotopic release rates to the atmosphere, and the data needed to estimate plume rise. If released fractions are used to quantify isotopic release rates, inventories of isotopes are included. • Radiological source terms used to represent release categories are developed using appropriate methods or codes (see Regulatory Position C.1.3.16). The objective of the site characterization is to provide information on the population distribution and patterns of land use and land cover in the vicinity and region of a site to a distance of 80 6 Radiological consequence analyses may be