ABSTRACT
A fault tree provides a logical and hierarchical description of an accident in terms of sequences and combinations of malfunctions of individual components and adverse operating conditions. Fault tree analysis is a powerful tool for assessing the reliability of complex large-scale systems. In conventional fault tree analysis, probabilities are assigned to the basic events of the system under consideration. These probabilities are combined according to the structure of the AND/OR fault tree. The most important advantage of a fuzzy fault tree approach is its ability to engage human expertise in an assessment of risk. The listing of minimal cut sets is useful in risk assessment studies; a simple algorithm for determining minimal cut sets has been developed by J. B. Fussell and W. E. Velsely. Fuzzy set theory provides a scheme for coping with the imprecision and ambiguity that arise out of human expression.
