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:
ts 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 sufficient to justify the proposed TS changes. The licensee is expected to use judgment in developing an appropriate (to support regulatory decisionmaking) risk argument to justify the proposed TS changes, including the appropriate blend of quantitative and qualitative assessments. 2.5 Comparison of Risk of Available Alternatives In support of a TS change, available alternatives are sometimes compared to justify the TS change. For changes in TS CTs, such cases primarily involve comparing the risk of shutting down with the risk of continuing power operation, given that the plant is not meeting one or more TS LCOs. Such comparisons can be used to justify the increase in at-power risk associated with the TS change by averting some transition or shutdown risk. In the case of an SF change, the beneficial and adverse impacts similarly can be compared. The modified SF should be chosen so that the benefit of testing is at least equal to or greater than the adverse 4 For one-time-only CT changes, the ICCDP and ICLERP acceptance guidelines of 1×10-5 and 1×10-6, respectively, are established for compatibility with the ICDP and ILERP limits of Section 11 in NUMARC 93-01, which is applicable for voluntary maintenance activities requiring risk-management actions. DG-1287, Page 23 effects of testing. For example, if the calibration of relays in the reactor protection system causes plant transients, the risk from the test-caused transients is then estimated and compared with the test-limited risk of a reduced SF. In using such guidelines, the following considerations apply: a. The uncertainty associated with the two measures being compared can differ and should be considered in deciding on an acceptable change. b. When the risk measures associated with all alternatives are