Document: NRC Regulatory Guide
Document ID: db0c5d18-2d27-4720-8935-40b402e52f9a
Document Type: regulatory_guide
Title: Guidance for a Technology-Inclusive, Risk-Informed, and Performance-Based Methodology to Inform the Licensing Basis and Content of Applications for Licenses, Certifications, and Approvals for Non-Light Water Reactors + HISTORY - HISTORY 05/2019 – Issued DG-1353 , Proposed Revision 0
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML1831/ML18312A242.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.233
CFR Part: 
CFR Title: 

Content:
es among the physical barriers. The PRA complexity should reflect the as-designed reactor plant, which, in turn, may incorporate the simple systems, inherent safety characteristics, and limited public health hazard associated with a specific advanced non-LWR design. The process supports the categorization and evaluation of LBEs in terms of estimated frequencies and consequences of event sequences or event families (groupings of event sequences having similar initiating events, challenges to plant safety functions, plant response, end state, and mechanistic source term). The event sequences and related estimations of frequencies and consequences include equipment malfunctions caused by internal and external hazards. If applicable, the PRA should include event sequences involving two or more reactor modules as well as two or more sources of radioactive material, which could include waste processing and storage systems. NEI 18-04 focuses on safety functions and the identification of SSCs needed to fulfill those functions. The plotting of event sequences, considering frequencies and consequences, with the F-C targets supports defining the SSC capabilities and reliabilities needed to support the design process and inform the content of applications. Uncertainties related to event sequences, plant behavior, assumed reliability of SSCs, and other aspects of the estimation of event frequencies and consequences need to be considered. Uncertainties are addressed, in part, by assessing 6 NEI 18-04 points out that applications made under 10 CFR Part 52 are required to include a description of PRA results. SRM-SECY-15-002, “Proposed Updates of Licensing Policies, Rules, and Guidance for Future New Reactor Applications, dated September 22, 2015 (ADAMS Accession No. ML15266A023) confirmed the Commission’s expectations that PRAs would be developed and described in new reactor applications under 10 CFR Part 50. DG-1353, Page 12 event sequences on the F-C target based on the