Document: NUREG-0800
Document ID: e32f0820-4e33-476e-aa36-4ca8c2c64af0
Document Type: srp
Title: Use of Probabilistic Risk Assessment in Plant-Specific, Risk-Informed Decisionmaking:
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0119/ML011940192.pdf
Revision Date: 2023-06
Chapter: 19
Section ID: 19.0
CFR Part: 
CFR Title: 

Content:
in December 2002. In addition, the various engineering professional societies are considering developing a Standard for performing a fire PRA. SRP 19-18 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 RG 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 which affect safety-related equipment and activities will meet the quality guidelines described in RG 1.174. 111.2.2.5 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. 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 satisfied. Section 2.2.4 of RG 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 (ACDF and &LERF) along the y-axis (Figures Il1-1 and 111-2), 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. There