Document: NUREG-0800
Document ID: 7916b088-fb90-4163-84fe-027bd315bcc5
Document Type: srp
Title: REVIEW OF RISK INFORMATION USED TO SUPPORT PERMANENT PLANT-
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0717/ML071700658.pdf
Revision Date: 2023-06
Chapter: 19
Section ID: 19.2
CFR Part: 
CFR Title: 

Content:
RA model or by appropriate changes to the logic model structure. For full-scale applications of the PRA, for example, this should be reflected in a quantification of the impact on the PRA results. For applications like component categorization, however, sensitivity studies on the effects of the change may be sufficient. Similarly, for other applications, it may be adequate to define the qualitative relationship of the impact on the PRA elements, or it may simply be necessary to identify which elements are impacted. The review procedure for this element is therefore intended to verify that the submittal appropriately accounts for the effects of the changes on SSC reliability and unavailability or on operator actions. Where applicable, reviewers should also evaluate the modeling and quantification of the effects of the change to ensure that the models are appropriate and that the results can be supported by plant and/or industry data. III.2.2.2 Scope of Analysis The necessary scope of a PRA supporting risk-informed requests will depend on the specific application. Although the assessment of risk implications (in light of the acceptance guidelines defined in Regulatory Guide 1.174) requires that all plant operating modes and initiating events be addressed, it is not necessary in risk-informed regulation that licensees submit PRAs that treat all plant operating modes and all initiating events. Instead, when full-scope PRAs are not available, reviewers should ensure that the submitted findings are supportable on the basis of traditional engineering analyses or other plant operational information that addresses modes an initiators not analyzed in the base PRA. For plant modes and initiators not analyzed in the PRA (such as shutdown, seismic events, fire, floods and severe weather), the licensee should consider the effects of the change and provide the rationale for why additional PRA analyses are not necessary. This rationale could be addressed by assessing the level of