Probabilistic non-destructive assay of radioactive waste

Random loading of fissile material in radwaste containers may lead to significant uncertainty in the determination of the fissile content by non-destructive assay. An analytical procedure is developed for evaluating this uncertainty. The procedure is suitable for low fissile density, may be applied to single or multiple measurements and accounts for possible size distribution of the fissile particles. It is shown how the probabilistic interpretation of non-destructive assay depends fundamentally on the response function of the assay apparatus. This relationship is exploited to develop quantitative criteria for the degree of mass-resolution capability of the apparatus. These criteria provide useful guidelines for the optimal design of apparatus for non-destructive assay.