A probabilistic fire analysis of power cable routes to nuclear reactor shutdown systems

This work presents a probabilistic fire approach for power cables of equipment necessary to a safe nuclear reactor shutdown when a probabilistic safety assessment is unavailable. The objective is to reduce the conservatism when applying the concept of defense in depth related to fire protection. The necessary equipment for a safe shutdown, (electric power cable routes), the selected compartment fire load, the fire detection and suppression system as well as the compartment fire frequency are identified. The burning time, the time to damage cables and the detection time are determined. The fire detection system reliability, the manual fire fighting time and the automatic fire suppression system implementation are determined in order to evaluate the reduction in the loss frequency of the selected safety system. (author)