Development of the success criteria analysis method for operator intervention scenarios

Abstract

The available time for operator which is the success criteria of manual-operated safety system is obtained from thermal-hydraulic analysis in current level 1 probabilistic safety analysis. However, performance time of emergency operating procedure should be considered on the success criteria of manual-operated safety system because operator diagnoses the accident and performs the required action following the procedure in real situation. In this dissertation, a method to analyze possible paths with probabilities and performance time distributions to perform the manual-operated safety system was developed using multi convolutions of performance time distributions for each steps and the plant condition from the thermal-hydraulic analysis. Also, a method to obtain the success criteria considering the performance time of the procedure was developed for operator intervention scenarios. In the case study, it was analyzed that how many operators can utilize the available time based on the time obtained from the thermal-hydraulic analysis for feed and bleed operation under the total loss of feed water accident, and the available time valid for more operators was suggested obtained from the method developed in this study.