Document: NUREG-0800
Document ID: f60cdc8f-3c25-45c3-a1d3-b0f530961625
Document Type: srp
Title: DETERMINING THE TECHNICAL ADEQUACY OF PROBABILISTIC RISK
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML1219/ML12193A107.pdf
Revision Date: 2023-06
Chapter: 19
Section ID: 19.1
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Content:
e risk contributions not addressed by a PRA model are not significant to the decision. This is discussed more fully in NUREG-1855, “Guidance on the Treatment of Uncertainties Associated with PRAs in Risk-Informed Decision Making.” Decision makers may address these omissions in other ways. Examples of allowances include the introduction of compensatory measures, and restriction of the implementation of the proposed change to the aspects of the plant covered by the risk model. This SRP section does not address this aspect of decision making but focuses on what PRA information should be provided. The reviewer’s responsibility is to understand the scope of the PRA used in the decision making so that the appropriate appendices to RG 1.200 are identified as references for the review. III.1.3 Parts of the PRA Model Used in Application To assess the technical adequacy of the PRA input for a decision, the licensee should identify which parts of the PRA are used to provide the PRA results that will be compared to acceptance criteria or guidelines that apply to the application. For example, for license amendments, these parts of the PRA include not only the logic model events onto which the cause-effect relationships are mapped, but also all the events that appear together with those events in the affected accident sequences, and the parts of the analysis needed to evaluate the necessary results. For some applications, this may be a limited set, but for others (e.g., risk-informing the scope of special treatment requirements) all parts of the PRA model are relevant. In addition, when the assessed impact of a proposed change is measured in terms of ΔCDF or ΔLERF as 19.1- 6 Rev. 3 – September 2012 described in RG 1.174, the total CDF and LERF should also be considered, broadening the scope of review for technical adequacy. The reviewer, in applying this SRP section, should become familiar with those parts of the PRA identified as supporting the PRA results. III.2