A Method to Calculate the Importance Measures of Complex System Equipment Based on PSA

The calculation of importance measures is based on the individual basic event in probabilistic safety assessment (PSA). In some cases, the decision maker usually concerns about the equipment or component importance measures, which can not be calculated directly in PSA. In this paper, several methods to calculate component importance measures are discussed first. a new importance measure called "Equipment Probability Differential Importance Measure(EPDIM)" for complex system equipment is proposed based on Component Probability Differential Importance Measure(CPDIM). An example is used to demonstrate EPDIM.