Setpoint Methodology Improvement Considering Beyond Design Basis Events for Safety-Related Instrumentation

According to the nuclear regulations and industry standards, the trip setpoint and the allowable value for safety-related instrumentation have been determined considering design basis events. In order to enhance the safety of nuclear power plants, this paper provides an improved setpoint determination methodology that incorporates not only a design basis event but also a beyond design basis event. The methodology is applied to the plant protection systems for the advanced power reactor 1400 and the optimized power reactor 1000 nuclear power plants in Korea. The results of a quantitative evaluation performed for those plants are presented herein. The results demonstrate that the proposed methodology is able to enhance the nuclear power plant´s safety by determining more reasonable setpoints that can cover beyond design basis events.