Document: NRC Regulatory Guide
Document ID: fa5814c8-b91a-435c-8ee0-5cd4915f8b80
Document Type: regulatory_guide
Title: Performance-Based Emergency Preparedness for Small Modular Reactors, Non-Light-Water Reactors, and Non-Power Production or Utilization Facilities
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML1808/ML18082A044.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.242
CFR Part: 
CFR Title: 

Content:
of an atmospheric transport model should also involve selection of a conceptual approach for treatment of wet and dry deposition. Any DG-1350, Appendix A, Page A-3 assumptions made in the atmospheric transport model should be identified so that the analyst can evaluate the suitability of the model for their particular application. A-3.4 Exposure Parameters The relevant exposure pathways should be identified. For example, exposure to both airborne and deposited radioactivity from atmospheric releases would involve both external (groundshine and cloudshine) and internal (inhalation of airborne material during cloud passage or as a result of resuspension) exposure. Assumptions regarding the geographic distribution of the receptor population, if any, should be identified. Estimation of peak centerline doses as a function of distance only implicitly assumes that no credit is being taken for the distribution of population around the site. In order to assess the dose, the exposure parameters (e.g., shielding factors, breathing rates, exposure durations, etc.) would need to be characterized. No credit for pre-planned protective actions such as evacuation or sheltering should be assumed in the development of factors such as the exposure durations and shielding factors. A-3.5 Dose Estimation for Pathway Contributors The dose estimation is carried out by combining the results of the release, transport, and exposure assessment with a recognized source of dose conversion factors to estimate dose-distance curves for comparison to the one rem total effective dose equivalent (TEDE) criteria. The distance at which the doses are evaluated should be identified and explained. For example, the dose may simply be estimated at the site boundary to demonstrate that it is sufficiently low, or may be evaluated over a range of distances from the site boundary. A-3.6 Probabilistic Dose Aggregation The method for aggregating doses from different source terms, given consideration of their