Combination and evaluation of expert opinions characterized in terms of fuzzy probabilities

This study presents a new approach for combining expert opinions to assess an uncertainty inherent in accident management. The need to work with rare events and limited data in accident management leads analysts to use expert opinions extensively. Unlike the conventional approach using point-valued probabilities, this study proposes the use of fuzzy probabilities to represent expert opinions. The use of fuzzy probability has an advantage over the conventional approach when an expertʹs judgment is based on limited data and imprecise knowledge. The study demonstrates a method of combining and propagating fuzzy probabilities. Finally, the proposed methodology is applied to the evaluation of the probability of a bottom head failure for the flooded case in the Peach Bottom BWR nuclear power plant.