Safety assessment of low and intermediate levels radioactive waste facilities using fuzzy logic: a case example

Uncertainty analysis is an important part of low and intermediate level radioactive waste facilities safety assessment. Very often experts opinion are used in the decision making process due to the uncertainty and natural variability in parameters and the great complexity of parameters interactions and consequent ambiguity on data interpretation. Probability techniques have been used on data analysis in order to bring a formal mathematical treatment to the data, to understand the range of potential outcomes in the prediction, and to enhance confidence in the results. However, these uncertainties are subjective in nature and therefore, despite the use of probabilistic analysis, there is still subjectivism in the predictions, for example, on the determination of the probability distribution functions. This paper presents an approach, based on fuzzy logic, as a complementary methodology for data analysis and interpretation, for low and intermediate level radioactive waste repositories. One such approach is the use of possibilistic analysis or fuzzy set theory. This methodology help make a simpler picture of the several interactions in such a complex system while keeping the original information.