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:
ting data: a. Performance indicator reports: These reports list the number of reactor trips and safety system actuations at each plant, the date of the events, and the numbers of the relevant licensee event reports (LERs). b. LER system: LERs describe reactor trips. When test-caused transients for a single plant are evaluated, the plant-specific data may be sparse unless the plant’s operating experience covers a substantial period. When plant-specific data are sparse, more data may be used from the operating experience of other plants of similar vintage (e.g., other Type 4 Boiling-Water Reactors (BWR/4s)), assuming the likelihood of occurrence of test-caused transients is similar for all the plants in the database. (The performance indicator reports categorize plants according to design classes.) Testing, however, tends to be very plant specific; therefore, cross-plant data applicability must be evaluated in detail. A-2.3.7 Data for Evaluating Transition Risk Data available in a PRA for full-power operation provide the basic information for evaluating the transition risks when a plant is being shut down for an LCO. In addition, the PRA for low-power and shutdown operations, if available, will significantly ease the acquisition of the data necessary for DG-1287, Appendix A, Page A-11 evaluating the risk of shutdown. The low-power and shutdown PRAs typically contain relevant data, such as the durations of shutdown phases and the frequencies of initiators that may occur during shutdown operation (e.g., loss of RHR). The full-power PRA is available for most operating plants, but the low-power and shutdown PRAs are only available for some plants. Hence, the following data are needed to evaluate transition risk assuming that only data from a full-power PRA are available: a. Plant-specific data on shutdown operations: To analyze shutdown phases in detail, plant-specific information may be needed, such as operating and abnormal procedures, shift supervisor’s log books,