Dynamic response of dry cask storage systems for spent nuclear fuel to near field blast loading

Abstract Dry storage casks are the most common form of spent nuclear fuel (SNF) storage in the United States. An explosion near a spent nuclear storage facility poses a serious public risk due to the potential of radioactive leakage. In this study, for the first time, the structural performance of vertical steel–concrete-steel sandwich (SCSS) and reinforced concrete (RC) casks under blast loading scenarios is studied using explicit finite element simulations considering material and geometric nonlinearity and strain rate effects. The response of the cask is investigated in terms of stress levels, deformations, and peak accelerations. The conventional weapons (CONWEP) model was used to induce a blast load on the structure at varying blast charges. The accelerations experienced by the canister and the fuel assemblies, which are critical for design are estimated. The inherent vibration damping characteristics of the cask are evaluated, and a novel damper configuration is proposed to improve the energy dissipation capacity of the system. The results showed that the general integrity of the cask could be preserved in the presence of a thick reinforced concrete layer. However, due to the lack of a damping mechanism, the blast wave can propagate through the system and result in very large accelerations in the canister and the fuel assemblies. Results also revealed that the SCSS configuration has a more ductile response compared to the RC design. The results of this study could be used for the safety evaluation and design optimization of current casks in service and other cylindrical composite containment structures.