Mapping Fault Tree into Fuzzy Algorithms for Nuclear Safety Analysis

In this paper a new method for mapping fault tree into fuzzy algorithms is introduced. This method is based on the minimal cut sets of a fault tree. This method is characterized by its one-to-one mapping from fault tree (FT) to fuzzy algorithm (FA) and vice versa. So it is consider a canonical method to map FTs into FA. Fault tree analysis (FTA) is a risk analysis technique to assess likelihood (in a probabilistic context) of an accident. The objective data available to estimate the likelihood is often missing, and even if available, is subject to incompleteness and imprecision or vagueness. Without addressing incompleteness and imprecision in the available data, FTA and subsequent risk analysis give a false impression of precision and correctness that undermines the overall credibility of the process. To solve this problem, qualitative justification in the context of failure possibilities can be used as alternative for quantitative justification. To this end, fuzzy reliability approach can be used as solution. While the estimation of failure probabilities of rare events with high consequences is the hot topic of nuclear power plants probabilistic safety assessment, the proposed method is used to estimate the possibility of fission products release from nuclear power plants due to core damage. Key-Words: Fault Trees, Fuzzy Algorithms, Minimal Cut Sets, and Nuclear Safety