Document: NUREG-0800
Document ID: ac43f632-9db1-4857-9f56-bfba45965456
Document Type: srp
Title: * These are modifications to a plant’s design, operations, or other activities that require NRC approval. These modifica
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0232/ML023250195.pdf
Revision Date: 2023-06
Chapter: 19
Section ID: 19
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CFR Title: 

Content:
propriate quality requirements will also apply to the PRA. In this context, therefore, a licensee would be expected to control PRA activity in a manner commensurate with its impact on the facility’s design and licensing basis. Section 2.5 of Regulatory Guide 1.174 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 Section II) has been SRP 19-19 satisfied. Section 2.2.4 of Regulatory Guide 1.174 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