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:
to two general groups: those for which some change is proposed, and those for which no change is proposed. It is the potential impact of the application on the particular SSCs and human actions and on the measures of risk which ultimately determines which SSCs and human actions should be regarded as safety-significant. Since different applications impact different SSCs and human actions, it is reasonable to expect that the categorization could be different for different applications. Thus, the question being addressed by the application is, for which groups of SSCs and human actions can the change be made such that there will be no more than an insignificant increase in the risk to the health and safety of the public. This impact on overall risk should be related back to the criteria for acceptable changes in the risk measures identified in Regulatory Guide 1.174. It is those groups for which changes can be made that satisfy these criteria that can be regarded as low safety-significant in the context of the specific application. Thus, the most appropriate way to address the categorization is through a requantification of the risk measures. However, the feasibility of performing such risk quantification has been questioned for those applications for which a method for evaluating the impact of the change on SSC unavailability is not obviously available. In such instances, an acceptable alternative to requantification of risk is to categorize SSCs and human actions using an integrated decisionmaking process (such as the use of an Expert Panel), with PRA importance measures as input. This appendix discusses the issues that reviewers should address for this approach. Section C.1 of this appendix discusses the technical issues associated with the use of PRA importance measures, and Section C.2 of this appendix discusses the use of the importance measures by the decisionmaking panel. C.1 Use of Importance Measures a. Areas of Review 19.2-75 June 2007 In the implementation