Document: NRC Regulatory Guide
Document ID: 8a2332d3-66ca-40af-84e1-507db8b26559
Document Type: regulatory_guide
Title: TRIAL - Acceptability of Probabilistic Risk Assessment Results for Non-Light Water Reactor Risk-Informed Activities
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML2123/ML21235A008.pdf
Revision Date: 2023-05
Chapter: 
Section ID: RG-1.247
CFR Part: 
CFR Title: 

Content:
he characteristics and attributes needed to achieve the objectives of an event sequence analysis PRA element are as follows: • The barriers to radionuclide release and the safety functions necessary to protect each barrier for each source are defined in terms of radioactive material sources and described for each POS. • The analysis should reflect plant-specific dependencies that impact significant event sequences in the event sequence structure. • The analysis should account for individual function successes, mission times, and time windows for each safety function operator action. • The analysis should include functional, phenomenological, and operational dependencies and interfaces. • The analysis should identify and characterize the sources of model uncertainty related to the event sequence analysis PRA element. • The analysis should fully document the event sequence analysis PRA element to provide traceability of the work. C.1.3.4 Success Criteria Analysis Probabilistic Risk Assessment Element This section identifies the objectives and the characteristics and attributes of the success criteria analysis PRA element for an NLWR PRA that addresses all radiological sources, all hazards, all POSs, and all levels of PRA analysis. The objective of the success criteria analysis PRA element is to determine the minimum requirements for each function (and ultimately the systems used to perform the functions) to prevent or to mitigate a release given an initiating event. The requirements defining the success criteria are based on acceptable engineering analyses that represent the design and operation of the plant under consideration. For a function to be successful, the criteria depend on the initiator and the conditions created by the initiator. The computer codes used to perform the analyses for developing the success criteria are validated and verified for both technical integrity and suitability to assess plant conditions of interest for prevention of a