Assessing Maintenance Intervals for Reactor Systems Using Monte Carlo Simulation

Summary This study applied a Monte Carlo Simulation (MCS) framework to optimize maintenance intervals for reactor overpressure protection systems, effectively overcoming the limitations of traditional deterministic methods, which do not account for uncertainties in component failure rates. The investigated protection system consists of two parallel subsystems—an alarm system (pressure switch + alarm indicator) and a shutdown system (pressure switch + solenoid valve)—designed to ensure safe operation under overpressure conditions. Using a probabilistic approach, the traditional method estimated the maintenance interval at 13.7 years; however, when uncertainties in each component’s failure rate were incorporated through MCS, the analysis indicated that health checks should be performed at least every 9.5 years. This shorter, risk-informed interval better reflects real-world variability, ensuring the probability of failure on demand remains within acceptable safety limits while maintaining operational efficiency.