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:
o achieve the objectives of the site characterization PRA analysis element are as follows: • The distribution of the population in the vicinity and region of a site to a distance of 80 km (50 mi) is based on recognized demographic sources and adjusted for population growth. • Land use and land cover information in the vicinity and region of a site to a distance of 80 km (50 mi) is based on recognized sources of local or regional geographic information. The objective of the meteorological data analysis is to evaluate and select the meteorological data used for the atmospheric transport and diffusion analysis. The characteristics and attributes needed to achieve the objectives of the meteorological data analysis PRA analysis element are as follows: • At least one full annual cycle of hourly meteorological data that are representative of long-term meteorological conditions of the site is compiled. Depending on the application, at least two full annual cycles of hourly meteorological data may be needed. Regulatory Guide 1.23 (Ref. 38) provides information on the amount of meteorological data typically needed at different licensing stages and may be used to justify the amount of meteorological data that is collected and used in the analysis. • Meteorological data are of acceptable quality and completeness. Regulatory Guide 1.23 provides information regarding assessment of the quality and completeness of meteorological data and may be used to evaluate meteorological data quality and completeness. • Meteorological data include, at a minimum, data on windspeed, wind direction, atmospheric stability, precipitation, and the depth of the atmospheric mixing layer. Regulatory Guide 1.23 provides information that may be used to determine atmospheric stability from meteorological data. • Meteorological data sets with missing data are completed by substituting data using interpolation techniques, substitution techniques using data from onsite sources (e.g., from a