Optimal maintenance policies for a system with multiechelon risks

Aged fossil-fired power plants, which need the maintenance or their steady operations, are on the great increase in apan. A various kinds of severe failures are immanent in plants, and the occurrence probability of them of aged plants might be much higher than that of new ones. Such failures occur when the cumulative stress of plant surpasses,heir peculiar stress levels. Appropriate preventive maintenance should be considered because corrective maintenances at failures are so expensive. N kinds of failures are considered and the preventive maintenance performed when the cumulative stress level exceeds the managerial level k. The expected cost per unit time between maintenances is secured. and the optimal managerial level k* which minimizes is analytically discussed.