Drop Test of 1/3 Scale Model for Modified TK Type Transport and Storage Cask - Experimental Results of Drop Test -

Transnuclear and Kobe Steel have been developed and designed the transport and storage casks called TK type series. The TK type cask consists of a forging shell body with neutron shielding material, a primary lid, a secondary lid as storage configuration, and a tertiary lid and shock absorbing covers (SAC) made of redwood are additionally attached for transport condition. As phase-1, drop tests using 1/3 scale model cask for the basic type of TK series were already done 1).This time as phase-2, the drop tests for the modified cask have been done. This cask is designed to optimize lids and top SAC for decreasing of deformation of lids, etc. against delayed impact under vertical drop test. The model was 1/3 scale, the height of drop test was 9m and these tests were performed with 3 different conditions, i.e. horizontal, vertical, and slap-down. The trends of G-values and deformations between these 2 series of tests were almost same. It was also confirmed that the G-values for all conditions were less than the target values and that the deformations of the SACs were also within the target range without bottoming. In addition, no significant tears on outer cover plates of stainless steel for SACs or no outer damage of the cask itself were observed. Therefore the structural integrity of the modified TK type cask is confirmed by phase-2 tests as same as the results of phase-1. And these test results are used for confirming validity of the safety analysis procedures on 9m drop test conditions for TK type casks.