Uncertainty Modeling of Radiological Risk Using Probability - Possibility Combination

Radiological risk analysis is an essential component for evaluating the performance criteria of nuclear power plant. Assessment of the radiological risk corresponding to the inhalation exposure finally guarantees that whether release is within limit or beyond limit, further dictating the performance of the system. However, all the parameters involved in the model used to evaluate the risk from various pathways of exposure are not possible to describe by the probability distribution. Parameters having insufficient knowledge are characterized by the possibility distribution. Possibility distribution of the parameter is addressed in terms of fuzzy set theory. The present paper proposed a probability-possibility combination in uncertainty modeling of the radiological risk keeping in mind that uncertainty analysis is an important issue for making any decision on radiological safety related problems. The paper describes the methodology of the probability-possibility combination. Methodology is illustrated with a case study of postulated release of radioactive iodine following the failure of the safety system.