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
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hange, reviewers should also address the following factors: • The cumulative impact of previous changes and the trend in CDF and LERF (the licensee's risk management approach), • The impact of the proposed change on operational complexity, burden on the operating staff, and overall safety practices, • Plant-specific performance and other factors, including, for example, siting factors, inspection findings, performance indicators, operational events, and Level 3 PRA information if available, 19.2-24 June 2007 • The benefit of the change in relation to its CDF/LERF increase and whether it is practical to accomplish the change with a smaller CDF/LERF impact, • Practical actions that could reduce CDF/LERF when there is reason to believe that the baseline CDF/LERF are above the guideline values (i.e., 10-4 and 10-5 per reactor year). III.2.3.1 Review of Combined Change Requests In assessing combined change requests, reviewers should evaluate the acceptability of each of the individual changes with respect to the defense-in-depth and safety margin guidelines discussed in Subsection III.2.1 of this SRP section. In addition, reviewers should evaluate the overall risk impact of the combined changes using the guidelines discussed in Subsection III.2.2 of this SRP section. In evaluating the overall (i.e., combined) risk impact, reviewers should take into account the relationship between the individual changes. For example, in combined change requests for which individual changes that increase risk are compensated for by other changes that decrease risk, reviewers should evaluate and understand the major contributors to both the risk increase and risk decrease, including the analysis assumptions and uncertainties from each contributor that might affect the decision process. Combining risk impacts from the individual contributors is prudent when the contributors are closely related in terms of analysis assumptions and uncertainty. Contributors could also be related if