Structural Evaluation of a Canister Drop inside a Vertical Concrete Cask

In preparation of lowering a welded canister containing fuel inside a vertical concrete cask (VCC), a bottom end drop of the canister into the VCC is postulated. The VCC is positioned on a trailer designed to move the loaded VCC, and the trailer is supported by a concrete floor. Pertinent to the evaluation are the existence of gaps which could result in secondary impact. Preliminary evaluations confirm that a significant gap could occur between the fuel and the canister bottom plate by the time the canister reached the bottom of the VCC. In addition to the developed gap between the canister and fuel, the trailer which is positioned off the floor could also have a variation in the gap between the floor and the bottom of the trailer. Since the duration of the free fall is at least an order of magnitude larger than the impact duration, two different analytical methods are used in the evaluation of each part of the solution. It is observed that the compliance of the canister has a significant effect on the gap developed between the fuel and the canister in the bottom end drop. Analyses were used to confirm that the canister boundary maintains its integrity in this bottom end drop. It was also observed that in a multibody impact, the ability to absorb energy by intervening components can significantly affect the loads applied to the canister.