The evaluation of dynamic impact behavior on SNF shipping cask for Korean standard nuclear power plant

The structural safety of spent fuel shipping cask is considered very stringent because serious effect can be brought to both mankind and environment in case of radioactive material leakage by the accident occurred during transportation. According to the IAEA Safety series, 10 CFR 71 and Regulatory Guide 7.8, the spent fuel shipping cask must be able to withstand 9m free drop impact onto an unyielding surface and 1m drop impact onto a mild steel bar in a position causing maximum damage. In this study, a structural safety evaluation was carried out for the conceptual design of SNF (Spent nuclear fuel) shipping cask for Korean standard nuclear power plant. Three dimensional dynamic structural analyses was executed using ABAQUS/Explicit code and dynamic impact behavior was analyzed to ensure the integrity of cask. The structural dimension of designed cask was obtained from criticality and shielding analyses. The cask is capable of loading 21 PWR CE-type spent fuel assemblies with a burn-up of 55,000 MWD/MTU and a cooling time of 7 years. The loaded cask weighs about 91.3 ton maximum. The whole cask system consists of cask body, cask lid, neutron shielding, outer shell and impact limiters