CASKS FOR TRANSPORTATION AND STORAGE OF RADIOACTIVE MATERIALS AS MUL Tl MASS SYSTEMS- ADDITIONAL STRESSES CAUSED BY KINEMATIC EFFECTS

If casks consist of several single components that are not attached to each other - for example inner and outer casks with a solid load, all inserted in a loose manner with significant clearance between them - special kinematic effects can take place during the drop tests. Measurements during drop test show that the contact of the inner mass with the outer mass is time-delayed relative to the contact of the outer mass with the target. As a consequence of this, it can happen that the stress will be lower than it would be if the components were attached to each other and the inertia force acted upon all masses in the same moment. On the other hand, relative movement during and after the impact - in other words, in the period of free rebound - can cause inner collisions that produce stress values which are higher than the values resulting from the initial impact itself. This paper shows some results of a drop test with a cask that is acting as a two-mass-system and the POLLUX-cask that is acting as a three-mass-system.