A CATHENA-based Approach to the Development of Shutdown System Reliability Test Profiles

Abstract

Reliability testing is a statistical means of safety-critical software qualification, in which inputs are simultaneously varied, and outputs checked against functional requirements. The test developers balance the need for realistic event scenarios and trip coverage completeness with the randomness and large number of test cases required for statistical validity. The need for realistic event scenarios and trip coverage completeness is met through use of the Canadian Algorithm for Thermalhydraulic Network Analysis (CATHENA) as a basis for test profile generation. The CATHENA-based approach ensures realistic scenarios and adequate coverage by starting with the analysis models. The developer converts the output file from each CATHENA run into a baseline profile, which is a text file containing a series of time-stamped trip computer input values representing the event scenario. The test developer then converts the baseline profiles into 10,000 test profiles by applying noise and other random effects to each signal.