Document: NRC Regulatory Guide
Document ID: acab976c-e936-49be-8c59-865767973599
Document Type: regulatory_guide
Title: Guidance for a Technology-Inclusive Content of Application Methodology to Inform the Licensing Basis and Content of Applications for Licenses, Certifications, and Approvals for Non-Light-Water Reactors (Rev. 1)
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML2319/ML23194A194.pdf
Revision Date: 2023-09
Chapter: 
Section ID: RG-1.253
CFR Part: 
CFR Title: 

Content:
equirements (SRs) provided in the ASME/ANS non-LWR PRA standard, as endorsed in RG 1.247 (for trial use) with clarifications and qualifications, provide an acceptable approach for developing PRA logic models. B.3.5 Section 4.3.11 of the ASME/ANS non-LWR PRA standard, which is endorsed in RG 1.247 (for trial use) with exceptions, provides an acceptable approach for performing a hazards screening analysis. B.3.6 Risk-informed supplemental evaluations may be used to disposition certain radiological sources, hazards, or POSs. NUREG-1855, Revision 1, “Guidance on the Treatment of Uncertainties Associated with PRAs in Risk-Informed Decisionmaking” (Ref. B-19), provides a generally acceptable approach for developing risk-informed supplemental evaluations. Section 1.3 of NUREG-1855 notes that the process described in NUREG-1855 “…is applicable to non-LWRs and reactors in the design stage; however, the screening criteria and the specific sources of uncertainty may not be applicable.” Consequently, non-LWR CP applicants who use the guidance in NUREG-1855 to develop risk-informed supplemental evaluations should (1) describe and justify the use of reactor-technology-specific screening criteria, and (2) explain how specific sources of uncertainty were identified and addressed. B.3.7 The CP applicant may disposition certain hazards by crediting DBHLs in lieu of modeling these hazards in the PRA. NEI 18-04, Revision 1, Section, 3.2.2, Task 6, p. 14, states: In many cases, it is expected that the initial selection of SR SSCs [safety-related structures, systems, and components] and selection of the DBAs [design-basis accidents] will be based on a PRA that includes internal events but has not yet been expanded to address external hazards. With the understanding that SR SSCs are required to be capable of performing their RSFs [required safety functions] in response to external events within 3 The non-LWR PRA standard uses the terms “requirement,” “require,” and other