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
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CFR Title: 

Content:
ld address the scope, quality, and robustness of the analysis, including consideration of uncertainties. The scope, level of detail, and quality of analysis is further discussed in Sections 111.2.2.2, 111.2.2.3, and 111.2.2.4 of this SRP chapter. The robustness of the results can be determined by developing an understanding of the contributors, the sources of uncertainty that impact the results, and their impact on whether the acceptance guidelines are met. The necessary sophistication of this evaluation depends on both the role the risk assessment plays in the decision and the magnitude of the potential risk impact. For those actions justified primarily by traditional engineering considerations and for which minimal risk impact is anticipated, a bounding estimate may be sufficient. For actions justified primarily by PRA considerations for which a substantial impact is possible or is to be offset with compensatory measures, an in-depth and comprehensive PRA analysis is generally needed. Comparison of Results with Acceptance Guidelines In the context of integrated decisionmaking, the acceptance guidelines should not be interpreted as being overly prescriptive. They are intended to provide an indication, in numerical terms, of what is considered acceptable. As such, the numerical values associated with defining the regions in Figures Il1-1 and 111-2 are approximate values used to indicate the changes that are generally acceptable. Furthermore, the state of knowledge (or epistemic) uncertainties associated with PRA calculations preclude a definitive decision (based purely on the numerical results) with respect to which region a given application belongs. The intent in making the comparison of the PRA results with the acceptance guidelines is to demonstrate with reasonable assurance that the proposal fulfills Principle 4 (discussed in Section II). The assessment of whether this has been demonstrated must be made on the basis of an understanding of the contributors to