Optimal maintenance policies for a system with given damage level

Aged fossil-fired power plants, which need the maintenance for their steady operations, are on the great increase in Japan. Appropriate maintenance plans for such plants have to be fast established, and be promptly executed at proper occasions with low maintenance expenses. From these points of view, this paper proposes four maintenance policies for a system with updated damage level, using the cumulative damage model. Expected cost, rates of each policy are derived, and optimal policies which minimize them are analytically discussed.