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: 

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characteristics, would require prior staff approval under 10 CFR 50.67. As an example, a licensee with an implementation involving only timing, such as relaxed closure time on isolation valves, could not use 10 CFR 50.59 as a mechanism to implement a modification involving a reanalysis of the MHA LOCA. However, the licensee could extend use of the timing characteristic to adjust the closure time on isolation valves not included in the original approval. 1.3 Scope of Required Analyses 1.3.1 Design Basis Radiological Analyses There are several regulatory requirements for which compliance is demonstrated, in part, by the evaluation of the radiological consequences of DBAs. A plant’s licensing bases may include, but are not limited to, the following: a. EQ of equipment (10 CFR 50.49, “Environmental Qualification of Electric Equipment Important to Safety for Nuclear Power Plants”), b. control room habitability (GDC 19 of Appendix A to 10 CFR Part 50), c. emergency response facility habitability (paragraph IV.E.8 of Appendix E to 10 CFR Part 50), d. AST (10 CFR 50.67), e. environmental reports (10 CFR Part 51, “Environmental Protection Regulations for Domestic Licensing and Related Regulatory Functions”) (Ref. 17), DG-1389, Page 12 f. facility siting (10 CFR 100.11),5 and g. early site permits, standard design certifications, combined licenses (10 CFR Part 52). There may be other areas in which the technical specification bases and various licensee commitments refer to evaluations that use an AST. A plant’s licensing bases may include, but are not limited to, the following sections of NUREG-0737, “Clarification of TMI Action Plan Requirements,” issued November 1980 (Ref. 18): a. post-accident access shielding (II.B.2), b. post-accident sampling capability (II.B.3), c. accident monitoring instrumentation (II.F.1), d. leakage control (III.D.1.1), e. emergency response facilities (III.A.1.2), and f. control room habitability (III.D.3.4). For applications