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:
change in the same manner as a permanent change. Even though NEI 96-07 applies to conducting 10 CFR 50.59 evaluations, a parallel can be drawn to TS CT extensions, in that temporary configurations or modifications extending beyond 90 days may no longer be considered temporary. Licensees requesting long-term CT extensions should be cognizant that such a request would increase the depth and level of detail of the staff’s review, and should ensure that any proposed measures to reduce the risk impact of the TS change (e.g., risk management actions, Tier 2 and 3 analyses, less reliance on programmatic activities as compensatory measures, demonstrating backup equipment reliability/availability) are commensurate with the proposed CT extension. Using the risk measures discussed in this RG, the change in risk should be calculated for TS changes and compared against the numerical guidelines referenced in RG 1.174; for CT changes, against the numerical guidelines presented below. In calculating the risk impact of the changed case, additional changes to be implemented as part of the change can be credited. For example, in seeking an SF change, if the test strategy is also to be changed, the effect of this should also be incorporated in the risk evaluation. TS conditions addressed by CTs are entered infrequently and are temporary by their very nature. However, TS do not typically restrict the frequency of entry into conditions addressed by CTs. Therefore, the staff provides the following TS acceptance guidelines specific to permanent CT changes for evaluating the risk associated with the revised CT, in addition to those acceptance guidelines in RG 1.174: a. The licensee has demonstrated that the TS CT change has only a small quantitative impact on plant risk. An ICCDP of less than 1x10-6 and an ICLERP of less than 1x10-7 are considered small for a single TS condition entry3 (Tier 1). b. The licensee has demonstrated that there are appropriate restrictions on dominant