Muon tomography optimization for dry cask spent nuclear fuel storage imaging

Dry cask spent fuel storage containers currently house much of the world’s spent nuclear fuel stores outside of spent fuel cooling pools. In order to maintain, continuity of knowledge of these containers, seals are applied. When these seals are broken, the containers must be relocated to spent fuel pools for visual inspection.  Large amounts of steel shielding, required for radiation safety, significantly attenuates both radiation emitted from the fuel itself and incoming radiographic probes such as x-ray and neutrons. As a result, the effectiveness of these more traditional radiographic probes is greatly diminished, and no other passive, in situ verification methods are currently in use. While promising results have been demonstrated, long measurement times limit the attractiveness of cosmic-ray muon radiography as a passive verification method. The work presented here compares performance of differing reconstruction techniques to draw recommendations for the optimization of future cosmic-ray muon tomography measurements. For tomographic imaging, the results show that using a plenoptic depth of field reconstruction method, rather than traditional backprojections, results in better imaging resolution for a limited number of views. The depth of field reconstruction method also requires a smaller number of views to reconstruct images useful in the verification of dry cask spent fuel storage containers.