OPTIMIZATION OF STANDBY SAFETY SYSTEM MAINTENANCE SCHEDULES IN NUCLEAR-POWER-PLANTS

A methodology and a computational scheme are developed based on dynami c programming (DP) to find the minimum cost maintenance schedule for n uclear power plant standby safety systems. Surveillance and testing ar e assumed to return the component to as-good-as-new condition whether accompanied by restorative maintenance only or full repair or replacem ent. The methodology defines component state as the number of unsurvei lled and untested maintenance intervals or stages, and the optimizatio n process is decomposed into (a) feasibility screening and (b) DP sear ch. This approach achieves a significant reduction in the state space over which the DP search is to be performed. The application of the sc heme is demonstrated on the ten-component high-pressure injection syst em of a pressurized water reactor. This demonstration indicates that t he scheme is viable and efficient and particularly suited to exploit a ny economies of scale and scope that may be present.