CREDO analysis: a comparison of liquid metal and water valve reliabilities

In this paper, data from the Centralized Reliability Data Organization (CREDO) are used to calculate failure rates and unscheduled maintenance frequencies for liquid metal valves. These failure rates and unscheduled maintenance frequencies are then compared to those calculated for valves from light water reactors. The liquid metal valves showed, in general, failure rates and unscheduled maintenance frequencies that are significantly lower than those of water valves (sometimes as much as an order of magnitude). Two possible reasons for the trend of lower failure rates and maintenance frequencies for liquid metal valves are then discussed