Fast verification of spent nuclear fuel dry casks using cosmic ray muons: Monte Carlo simulation study

An application of muon scattering tomography is investigated for the non-destructive verification of spent nuclear fuel dry storage casks in context of international treaty declarations in proving that the diversion of plutonium has not occurred during long term storage in the spent fuel storage facility. It was shown in the previous studies that the method of muon scattering tomography can provide a detailed 3-D image of the spent fuel container but with the measurement time required for that is in the range of a day or even longer. In this paper we investigate the feasibility of a fast verification of dry storage casks in order to obtain an immediate answer without a detailed 3-D image reconstruction of container content if at least one fuel assembly is missing. We have performed preliminary modelling using Geant4 of safeguards verification of spent fuel dry storage cask HI-STORM 190 with cosmic ray muons. The simulated data were analysed using the Point of Closest Approach method and Kolmogorov statistical test. To infer the state of content of dry casks we have performed the comparison and further classification of muon observable for the scenarios of one missing fuel assembly with respect to fully loaded casks. The results of this study indicate that one missing fuel assembly can be detected with measurement times of about one hour.