A Methodology for Calculating the Expected Number of Failures of a System Undergoing a Phased Mission

A procedure for determining the expected number of failures of systems undergoing phased missions is described. Approximations to this procedure are also presented. The emergency core cooling system of a boiling water reactor is analyzed to demonstrate this methodology. The results of this analysis show that these procedures have practical application and the approximations provide a close estimate to the exact expected number of failures.