PRA with CAFTA

CAFTA is a Probabilistic Risk Analysis (PRA) toolkit developed and maintained by Electric Power Research Institute (EPRI)

Most nuclear plants in the US use computer aided fault tree analysis (CAFTA) software for performing Fire Risk Analysis. Going along with CAFTA is FRANX, a logical database which determines the basic events which start a fire and its mappings.
It uses a Microsoft Access database to help generate fire scenarios using plant and component information, linking failure events modeled within the risk analysis to specific components, associated cables, and other information.

It allows for specific initiators to damage specific targets so the program can identify failure modes, and which targets to include or exclude in the scenario analysis. CAFTA is software used to develop fault trees that model the PRA credited systems, components, and actions used to mitigate initiating events that lead to a plant trip. It also allows for the quantification of fault trees to find measurable results for the likelihood of accidents and the drivers of risk.

FRANX can quantify the models as well, but it is typically used only for fire or flood accidents. CAFTA is used for all types of initiators.

Plant Data Model System Each plant has some sort of database that tracks relevant components, equipment, cables, cable raceways, and other plant data. A common methodology is called plant data model system (PDMS) The level of detail and amount of information that this database contains will vary, but it is used to gather component and cable links, location data, drawing, and document information, etc. Although most plants implement a similar design, PDMS’s vary in each plant in the amount of data, table content, and reference methods.