Document: NRC Regulatory Guide
Document ID: c7a40fcc-fc9d-4eb2-ad86-f9f5b0f04c82
Document Type: regulatory_guide
Title: Plant-Specific, Risk-Informed Decisionmaking:  Technical Specifications (Rev. 2)
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML1920/ML19206A489.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.177
CFR Part: 
CFR Title: 

Content:
LERP of less than 1x10-6 with effective compensatory measures implemented to reduce the sources of increased risk.4 b. The licensee has demonstrated that there are appropriate restrictions on dominant risk-significant configurations associated with the change (Tier 2). c. The licensee has implemented a risk-informed plant configuration control program. The licensee has implemented procedures to use, maintain, and control such a program (Tier 3). In the context of integrated decisionmaking, the acceptance guidelines should not be interpreted as overly prescriptive. They are intended to provide an indication, in numerical terms, 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. Furthermore, the state of knowledge, or epistemic uncertainties associated with PRA calculations preclude a definitive decision with respect to the acceptance of the proposed change based purely on the numerical results. The intent in comparing the PRA results with the acceptance guidelines is to demonstrate with reasonable assurance that Principle 4 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. In accordance with Regulatory Position C.2.6 of RG 1.174, NRC management would give increased attention to the application if the calculated values of the changes in the risk metrics and their base values, when appropriate, approach the acceptance guidelines. Therefore, if the risk metrics approach or even slightly exceed the acceptance guidelines, the licensee’s submittal should address the additional aspects of plant risk and operation discussed in Section C.2.6 of RG 1.174. There may be situations in which a nonquantitative assessment of risk (either alone or accompanied by quantitative assessment) is