Drop Analyses and Verification of the Spent Nuclear Fuel Transportation Cask Under Hypothetical Accident Conditions

According to IAEA regulations, the spent nuclear fuel transportation cask must be able to withstand a free drop from the height of 9 meters on an unyielding surface. The impact limiter of the cask absorbs most of the impact energy and reduces the deceleration loads on the cask and contents. In order to accurately estimate the safety of the cask and the spent nuclear fuel, the calculation of drop acceleration is very important. In this study, based on the absorption of energy by an impact limiter is equal to the work done in crushing a volume, the maximum deceleration is estimated during collision process between cask and the ground. Then using the LS-DYNA computer program to simulate the cask drop behavior of 9 meters free drop. By comparing the results of theoretical analysis, numerical simulation and actual drop tests, the cask maximum acceleration and the impact limiter deformation are in good agreement, which prove the validity of the spent nuclear fuel transportation cask drop analysis. The stress intensity results for 9 meters free drop loading cases satisfy the allowable stress limit criteria as presented in “ASME Boiler and Pressure Vessel Code”. The spent nuclear fuel transportation cask meets the requirements of IAEA in the 9m free drop hypothetical accident conditions.