Applicability of Rigid Polyurethane Foam to Laying Type Shock Absorber

We have succeeded in an application of the Rigid Polyurethane Foam (R-PUF) to shock absorber for a transport cask. In case of drop event at nuclear facility from the height of 40 meters or more, the obtained knowledge will be applied as laying type shock absorber that is located under the lifted cask in order to mitigate an impact force received to it. However, we had had no performance with regard to design and experiment for laying type shock absorber, although obtained an abundant data regarding the drop impact test by dropping the shock absorber for transportation cask in a free fall state and knowledge from them. To design laying type shock absorber, We try to apply the method of the Uniaxial Displacement Method (UDM), which is used in CRUSH code : a simplified computer program for impact analysis of radioactive material transport casks, to evaluate the impact acceleration of the cask body and the deformation of the shock absorber that is in free drop event. In this study, we carried out static compression tests and falling weight impact tests using some weights that have respectively different tip shapes to simulate various postures of the freely falling casks. This study definitely demonstrates the followings.(a)Comparison between the experiment results and the prediction values based on UDM shows that the analysis method by UDM can be used to design considering an effect caused by the tip shape. (b)It is possible to design the shock absorber considered by its density and an impact speed of the object regarding an influence by a shear failure of a material of shock absorber that an object went through. (c)The splitting and a deviation of the shock absorber rarely occur if some blocks of shock absorber are stacked regarding a splitting of a material of shock absorber.