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:
odology has been developed to be consistent with the approaches used in the NUREG-0396 quantitative analyses, to the extent that the details of those analyses could be discerned.” Key assumptions of the generalized methodology include the following: a. Adequate information on radiological source terms and, as appropriate, probabilistic risk assessment (PRA) is assumed to be available. See Appendix B for more information on the development of radiological source terms and PRA. DG-1350, Appendix A, Page A-2 b. The atmospheric release pathway is assumed to be the risk-dominant contributor to offsite doses (i.e., no consideration of direct exposures or releases to liquid pathways). c. The atmospheric release is assumed to consist of neutral density non-reactive aerosols or gasses (with radioactive decay and in-growth corrections as appropriate). If a release pathway requires more complex atmospheric transport modeling, additional analyses may be needed. d. Use of a straight-line Gaussian plume segment-type atmospheric dispersion model (with modifications as needed to account for near-field dispersion phenomena) to estimate atmospheric concentrations is assumed to be appropriate. If a more advanced method for dispersion modeling is used, the details of the methodology described in this document may need to be adapted to account for the use of such models. e. A specified exposure duration must be assumed to estimate doses, and no credit for protective actions is assumed over the specified exposure period. A-3. Generalized Methodology A-3.1 Source Terms For each release scenario for which doses are assessed, a quantitative radiological source term would be developed by specifying atmospheric release characteristics such as the time dependent isotopic release rates to the atmosphere, release durations, release locations, physical/chemical form, and plume buoyancy. A-3.2 Meteorological Input An analysis to develop meteorological data may be needed to evaluate a range of