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:
uences reflected in the LBEs sufficiently complete? Are the uncertainties in the estimation of LBE frequency, plant response to events, mechanistic source terms, and dose well characterized? Are there sources of uncertainty not adequately addressed? DG-1353, Page 20 • Have all risk significant LBEs and SSCs been identified? • Has the PRA evaluation provided an adequate assessment of “cliff-edge effects”? • Is the technical basis for identifying the required safety functions adequate? • Is the selection of the SR SSCs to perform the require safety functions appropriate? • Have protective measures to manage the risks of multimodule and multiradiological source accidents been adequately defined? • Have protective measures to manage the risks of all risk significant LBEs been identified, especially those with relatively high consequences? • Have protective measures to manage the risks for all risk-significant common-cause initiating events, such as support system faults, internal plant hazards such as fires and floods, and external hazards, been identified? • Is the risk benefit of all assigned protective measures well characterized (e.g., via sensitivity analyses)? The NEI 18-04 methodology for assessing DID includes an assessment of plant risk margins that compares the mean values of each LBE frequency and dose to the F-C target. A more conservative evaluation of margins is also performed that compares the 95th percentile upperbound values of each LBE frequency and dose to the F-C target. The IDP considers these margins within its deliberations on the adequacy of DID. Programmatic Defense in Depth Section 5.8 in NEI 18-04 identifies the following objectives for the IDP assessment to identifying appropriate programmatic controls: • Assure that adequate margins exist between the assessed LBE risks relative to the F-C target, including quantified uncertainties. • Assure that adequate margins exist between the assessed total plant risks relative to