Oblique 9-Meter Drop Test of Scale Model for KSC-7 Cask

A type B(U) shipping cask (KSC-7 cask) with a capacity of 7 PWR spent-fuel assemblies has been developed for transportation of domestic spent fuels from the storage pool of nuclear power plants to the interim storage facility. The KSC-7 cask was designed in consideration of 50,000 MWD/MTU burnup fuel with 1.5 years cooling time. According to the domestic and IAEA regulations(IAEA 1985a) for nuclear spent-fuel transport, all shipping casks should maintain their structural integrity against drop accident. A one-third scale model for the KSC-7 cask was designed and fabricated to confirm the structural design. A series of drop tests was conducted on this scale model by changing its impact limiters to verify that the cask is structurally adequate to survive hypothetical accident drop conditions. The nonlinear dynamic analysis with LS-DYNA3D code was carried out for the scale model prior to the drop tests to select test drop orientation(Ku et al. 1995). It was found from the analysis that a 20 degree bottom oblique drop condition will give the maximum damage to the KSC-7 cask among the possible drop orientations. In addition, this oblique drop impact showed very complicated impact behavior because of the sequential impacts with rotation of the cask after primary impact.