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:
roach described in NEI 18-04 and this RG involves the assessment of event categories that extend from benign to severe. The analysis of AOOs, DBEs, and BDBEs plays an important role in defining safety functions, classifying SSCs, and assessing DID for non- LWRs. The safety analysis report describes the analysis results for event sequences and related organization into event families. The PRA results are typically described in Chapter 19 of the safety analysis report, which could be expanded; a new section added to Chapter 15; or a new chapter created to include the analysis of AOOs, DBEs, and BDBEs. In addition to plant response information on SSC capabilities typically provided in deterministic evaluations, the description of AOOs, DBEs, and BDBEs DG-1353, Page 24 needs to include or point to key information identified in NEI 18-04, such as uncertainties and measures to ensure assumed SSC availabilities. Deterministic evaluations are usually described in Chapter 15 of safety analysis reports, and this remains an option for non-LWR applications developed using the NEI 18-04 methodology. Addressing DBAs in a separate section or chapter from the other LBEs could support maintaining the distinction between the deterministic analyses that assume only SR SSCs and the assessments of the remaining LBEs. A separate chapter might also help with the development of technical specifications and other elements of the licensing-basis documentation that are traditionally focused largely on SR SSCs. Descriptions related to the derivation of DBEHLs and protection of SR SSCs from design-basis external hazards are usually provided in Chapters 2 and 3 of safety analysis reports. Current guidance for safety analysis report format and content for LWRs (e.g., RG 1.206) does not include a specific section for DID assessments. The importance of DID assessments in the NEI 18-04 methodology and the more systematic approach to performing the assessments lends itself to separate sections or a