Defining the Group Importance Measures (GIM) with Applications in Space Shuttle PRA
In order to address some technical challenges raised in the Space Shuttle PRA development, we introduce in this paper, a definition of Group (or Gate-level) Importance Measure (GIM). The GIM measures defined here are extensions of Fussel-Vesely (FV) type importances, and can also be extended to other type of importance measures. Algorithms are also developed for extended SAPHIRE implementations. Examples are given to show that the GIMs can be obtained for every level of contributors modeled in a PRA. Such measure can be easily used to produce PRA risk ranking at all level of details, such as by phase, element, sequence bins, failure type or any combinations of specific group of event type and failure mode.
KeywordsFault Tree Importance Measure Component Group Risk Contribution Risk Ranking
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