Evaluation of the behaviour of the TK6 cask impacting real targets

Among other requirements for a Type B packages, the IAEA regulations require demonstration of its performance in 9m drops onto a flat unyielding target. Real targets are distinguished from unyielding targets in that a larger proportion of the drop energy can be absorbed by the target. The work presented in this paper formed part of the research project Evaluation of Safety of Casks Impacting Different Kinds of Targets, carried out jointly by Federal Institute for Materials Research and Testing (BAM), Gesellschaft für Nuklear-Behälter mbH (GNB), and Ove Arup & Partners International Ltd (Arup), and funded by the European Commission (Project EC-DGXVII/C/3. The work consisted of the following components: 1. literature survey of tests and analyses of package drops onto real targets; 2. development of a “simple” methodology for determining “global” response - decelerations and impact forces - for drops onto flat real targets. 3. detailed evaluation of cask response in drops onto flat real targets using finite element methods. This paper presents the work carried out by Arup in Component 3 - to evaluate - using finite element modelling in LS-DYNA - the detailed impact response of the TK6 cask in drops onto flat real targets, to examine both the global response (e.g. impact force, acceleration, target penetration etc) as well as local responses (e.g. bolt stresses, seal gaps, local interaction between cask and target etc), and to compare the response with drops onto an unyielding target.