Document: NRC Regulatory Guide
Document ID: b3da4d67-03d8-4f52-b04b-8e76d142c857
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:
) 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 uncertainty bands for the event in addition to the mean values of estimated frequencies and consequences. The analyses of event sequences and related uncertainties are inputs into the subsequent processes described in NEI 18-04 for the safety classification of SSCs and assessment of DID. NEI 18-04 Section 3.2.2, “LBE Selection Process,” describes an additional deterministic assessment of selected event sequences to supplement the consideration of AOOs, DBEs, and BDBEs for non-LWRs. A deterministic DBA is associated with each DBE that includes the required safety function challenges, but the DBA analysis is performed with the assumption that the required safety functions are performed by SR SSCs. Applicants typically describe these DBAs in Chapter 15 of a safety analysis report to support the deterministic safety analysis and show that the offsite consequences are below the reference values included in NRC regulations (e.g., 10 CFR 50.34). Although developed for LWRs, NRC RG 1.203, “Transient and Accident Analysis Methods,” provides additional guidance that would be generally applicable for analyzing DBAs for non-LWRs. NEI 18-04 describes how a set of design-basis external hazard levels (DBEHLs) will be selected to form an important part of the design and licensing bases. This will determine the design-basis seismic events and other external events that the SR SSCs will be required to withstand. When the DBEHLs are determined using traditional NRC-approved methodologies, this approach is generally consistent with current practices used for LWRs to define appropriate protection of SR SSCs against external hazards. The PRA models used for applications are expected to address the full spectrum of internal events and external hazards that pose challenges to the