Document: NRC Regulatory Guide
Document ID: 4d46a966-d280-43da-9b03-8b0abe7b29ce
Document Type: regulatory_guide
Title: Alternative Radiological Source Terms for Evaluating Design Basis Accidents at Nuclear Power Reactors (Rev. 1)
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML2120/ML21204A065.pdf
Revision Date: 2023-05
Chapter: 
Section ID: RG-1.183
CFR Part: 
CFR Title: 

Content:
esents a representative accident source term for a BWR and for a pressurized-water reactor (PWR). These source terms are characterized by the composition and magnitude of the radioactive material, the chemical and physical properties of the material, and the timing of the release to the containment. The NRC staff considered the applicability of the revised source terms to operating reactors and determined that the current analytical approach based on the source term in the Technical Information Document (TID)-14844, “Calculation of Distance Factors for Power and Test Reactor Sites,” dated March 1962 (Ref. 9), would continue to be adequate to protect public health and safety. Operating reactors licensed under that approach would not be required to reanalyze accidents using the revised source terms. However, the NRC staff determined that some operating reactor licensees might request to use an AST in analyses to support cost-beneficial licensing actions. The NRC staff, therefore, initiated several actions to provide a regulatory basis for operating reactors to use an AST3 in design basis analyses. These initiatives resulted in the development and issuance of the final rule for 10 CFR 50.67 (see Federal Register Notice (FRN) 64 FR 72001, December 23, 1999), and the subsequent issuance of RG 1.183, “Alternative Radiological Source Terms for Evaluating Design Basis Accidents at Nuclear Power Reactors,” Revision 0, issued July 2000 (Ref. 10), as implementing guidance for the rule. A series of RGs and SRP chapters describe the NRC’s traditional methods for calculating the radiological consequences of DBAs. The staff developed that guidance to be consistent with the TID-14844 source term and the whole body and thyroid dose guidelines stated in 10 CFR 100.11, “Determination of Exclusion Area, Low Population Zone, and Population Center Distance” (Ref. 11). Many of those analysis assumptions and methods are inconsistent with the AST and with the total effective