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:
conditional LERF with the subject equipment out of service and nominal expected equipment unavailabilities for other equipment permitted to be out of service by the TS) − (baseline LERF with nominal expected equipment unavailabilities)) × (total duration of a single CT under consideration). DG-1287, Page 11 involved. The objective of this part of the evaluation is to ensure that appropriate restrictions on dominant risk-significant configurations associated with the change are in place. In addition, compensatory measures that can mitigate any corresponding increase in risk (e.g., backup equipment, increased surveillance frequency, or upgraded procedures and training) should be identified and evaluated. c. Tier 3 is the establishment of a risk-informed plant configuration control program (i.e., configuration risk management program (CRMP)) to ensure that other potentially lower probability, but nonetheless risk-significant, configurations resulting from maintenance and other operational activities are identified and compensated for. If the Tier 2 assessment demonstrates, with reasonable assurance, that there are no risk-significant configurations involving the subject equipment, the application of Tier 3 to the condition addressed by the proposed CT may not be necessary. Although defense in depth is protected, to some degree, by the most current TS, application of the three-tiered approach to risk-informed TS CT changes will provide additional assurance that such changes to the licensing basis will not significantly impact defense in depth. Regulatory Positions C.2.3.1–2.3.7 and Appendix A to this RG discuss various issues related to the three-tiered approach. Specifically, Regulatory Positions C.2.3.1–2.3.5 and Appendix A outline issues associated with Tier 1, and Regulatory Positions C.2.3.6 and C.2.3.7 outline issues associated with Tier 2 and Tier 3, respectively. The NRC staff has identified several factors, discussed below, that should be considered in