Planning of maintenance intervals for power plant components including the unit costs of maintenance and risk

Well run management of routine repairs in a power plant and the costs related to it have an essential impact on the final price of electricity, and the appropriate selection of the time when maintenance services are performed is of special importance for power units which have already gone beyond the design operation time. Therefore, many new methods have appeared lately that allow an optimisation of maintenance works based on different criteria. The paper presents a methodology to optimise the period of time between maintenances of complex systems, taking account of unit costs of maintenance and keeping an appropriate level of safety which is represented by the level of technical risk. The Monte Carlo method and the selective search method are used for the optimisation, and the Fault Tree Analysis (FTA) is employed for the reliability calculations.