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:
el of reanalysis may not be necessary. For holders of operating licenses, as defined in the applicability section of 10 CFR 50.67, two categories of AST implementation are defined: full and selective. These are described in Regulatory Positions 1.2.1 and 1.2.2 below. For radiological consequence analyses for new reactor permit, license, approval or certification applications (e.g., those under 10 CFR 50.34(a)(1) or 10 CFR Part 52), the accident source term should consider all characteristics of a source term as defined in 10 CFR 50.2 and detailed in Regulatory Position 2 of this guide. Full and selective implementations, as used in the regulatory positions that follow, are not applicable to new reactor applicants. 1.2.1 Full Implementation Full implementation is a modification of the facility design basis that addresses all characteristics of the AST: specifically, the composition and magnitude of the radioactive material, its chemical and physical form, and the timing of its release. Full implementation revises the plant licensing basis to specify the AST in place of the previous accident source term and establishes the TEDE dose as the new acceptance criterion. This applies not only to the analyses performed in the application (which may include only a subset of the plant analyses), but also to all future design basis analyses. A full implementation is considered when, at a minimum, the application includes a reanalyzed MHA LOCA using the guidance in Appendix A to this guide. Regulatory Position 1.3 to this guide provide additional DG-1389, Page 11 guidance on the analysis. Since the AST and TEDE criteria would become part of the facility design basis, new applications of the AST would not require prior NRC approval unless the new application involves a change to a technical specification or unless the licensee’s 10 CFR 50.59 evaluation concludes that prior NRC approval is required. However, a change from an approved AST to a different AST that is not approved