Advanced progressive real coded genetic algorithm for nuclear system availability optimization through preventive maintenance scheduling

One of the main goals of reliability-centered maintenance programs is to find optimal maintenance strategies. Availability of emergency systems through preventive maintenance scheduling has an important role in Probabilistic Safety Analysis (PSA). Preventive maintenances can be replaced with reloading time maintenance and reduce unavailability of the system, especially in the last days of reload cycle. Of course, the emergency core cooling systems connect to circuit in accidents and control the intensity of the unavailability. For reducing unavailability of standby emergency systems, preventive maintenance scheduling method is offered. In this paper, an Advanced Progressive Real Coded Genetic Algorithm (APRCGA) is applied to optimize the availability of standby systems with preventive maintenance scheduling. Using APRCGA in nuclear maintenance systems and considering appropriate objective functions, the most suitable conditions are obtained. The preventive maintenance scheduling keeps unavailability of systems within safe and reliable conditions. In order to demonstrate the effectiveness of the proposed method, it is applied for two nuclear power plant emergency systems. First, for the nuclear emergency core cooling system of a two-loop pressurized water reactor, most available maintenance scheduling is presented. In the second case, for a four-loop pressurized water reactor, the maintenance scheduling for emergency core cooling system is proposed. The results are compared with those obtained by some standard maintenance policies, and previously published papers.