Document: NUREG-0800
Document ID: 7f6b0af0-d79e-4704-9eac-aa03109a7731
Document Type: srp
Title: RISK-INFORMED DECISIONMAKING: TECHNICAL SPECIFICATIONS
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0425/ML042520260.pdf
Revision Date: 2023-06
Chapter: 16
Section ID: 16.1
CFR Part: 
CFR Title: 

Content:
s to utilize, maintain, and control such a program (Tier 3). In the context of the integrated decisionmaking, the acceptance guidelines should not be applied in an overly prescriptive manner. They are intended to provide an indication, in numerical terns, of what is considered acceptable. As such, the numerical values above are approximate values that provide an indication of the changes that are generally acceptable. The intent in making the comparison of the PRA results with the acceptance guidelines is to demonstrate with reasonable assurance that Principle 4, discussed in the "Discussion" section of Regulatory Guide 1.177 (Ref. 8), is being met. This decision must be based on a full understanding of the contributors to the PRA results and the impacts of the uncertainties, both those that are explicitly accounted for in the results and those that are not. There may be situations in which a non quantitative assessment of risk (either alone or accompanied by quantitative assessment) is sufficient to justify TS changes. The licensee is expected to use judgment on the acceptability (to support regulatory decisionmaking) of the risk argument being considered, including the appropriate blend of quantitative and qualitative assessments. 2 ICCDP = [(conditional CDF with the subject equipment out of service) - (baseline CDF with nominal expected equipment unavailabilitics)] X (duration of single AOT under consideration). 3 The ICCDP acceptance guideline of 5.OE-7 is based upon the hypothetical situation in which the subject equipment at a representative plant is out of service for five hours, causing the CDF of the plant. with an assumed baseline CDF of 1 .OE-4 per reactor year, to conditionally increase to L.OE-3 per reactor year during the five-hour period. This basis assumes that the majority of repairs can be made in five hours or less and that the NRC has accepted this level of risk for existing operating plants. 4 ICLERP = [(conditional LERF with the subject