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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Content:
s design and licensing basis. Regulatory Guide 1.174, Section 2.5 describes the quality elements that apply to the licensee’s PRA activities. Reviewers should verify that the quality of analyses and performance programs that affect safety-related equipment and activities will meet the quality guidelines described in Regulatory Guide 1.174. III.2.2.5 Evaluation of Risk Impact In evaluating the risk impact from an application, reviewers should consider the proposed change in risk with regard to the acceptance guidelines, the cumulative and synergistic effects of the application on the overall plant risk profile, and the licensee’s risk management philosophy. Each of these items is discussed in the following subsections. III.2.2.5.1 Acceptance Guidelines for Risk Impact from the Application For many risk-informed applications, the licensee is expected to perform a quantitative estimate of the total impact of a proposed action to demonstrate that Principle 4 (see Subsection II of this SRP section) has been satisfied. Regulatory Guide 1.174, Section 2.2.4 discusses the acceptance guidelines for changes to the plant’s risk. To summarize, regions are established in the two planes generated by a measure of the baseline risk metrics (CDF and LERF) along the x-axis, and the change in those metrics (CDF and LERF) along the y-axis (Figures III-1 and III-2), and acceptance guidelines are established for each region as discussed below. These guidelines are intended for comparison with a full-scope assessment (including internal events, external events, and events that take place under full power, low power and shutdown conditions). However, reviewers should recognize that many PRAs are not full-scope assessments and the use of less than full-scope PRA information may be acceptable as discussed later. 19.2-18 June 2007 There are two acceptance guidelines, one for CDF and one for LERF, and both should be used. The guidelines for CDF are as follows: • If the application can