Document: NRC Regulatory Guide
Document ID: cde52d5a-adf9-49be-9d1f-59449dfca895
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:
ther errors that may impact equipment performance during the applicable POS are considered. (Note: The calibration errors or other errors may occur at a different POS from the POS being analyzed.) • The associated human error probabilities are quantified considering scenario- and plant-specific factors and including appropriate dependencies (e.g., between pre- and post-initiator HFEs). • The sources of model uncertainty related to the HRA PRA element are identified and analyzed. C.1.3.7 Data Analysis Probabilistic Risk Assessment Element This section identifies the objectives and the characteristics and attributes of the data analysis PRA element for an NLWR PRA that addresses all radiological sources, all hazards, all POSs, and all levels of PRA analysis. The objectives of the data analysis PRA element are as follows: • Clearly define the parameter boundaries. • Appropriately group components. RG 1.247, Page 24 • Ensure that the parameter data are consistent with parameter definitions. • Include relevant generic industry, design-specific, and plant-specific evidence in the parameter estimation. • Address uncertainty parameters. • Fully document the data analysis PRA element to provide traceability of the work. The data analysis PRA element quantifies the equipment failure probabilities and equipment unavailabilities of the modeled systems. The estimation process includes a mechanism for addressing uncertainties and has an ability to combine different sources of data in a coherent manner, including the relevant generic information and actual operating history and experience of the plant when it is of sufficient quality, as well as applicable generic experience. The characteristics and attributes needed to achieve the objectives of a data analysis PRA element are as follows: • The estimation of parameters associated with basic event probability models and unavailability events uses generic, design-specific, plant-specific data, or a combination of