Impact stress reduction by shell splitting in cask for transporting radioactive material

• High impact stress in shell of a container for transporting radioactive material.
• Reduction of impact stress by splitting shell into multiple parts.
• Impact simulations on simple objects to prove benefits of shell splitting.
• Explanation based on theory of bending of simply supported beam.
• Impact simulations on a simple cask showing up to 21% reduction in maximum stress.

Casks designed for transporting radioactive material are mandated to withstand drop from specific heights on hard ground. The maximum internal stress in the shell of the cask after such an impact needs to be as low as possible to ensure safety of the material being transported. This paper investigates the concept of splitting the shell of the radioactive transport container into multiple layers to reduce these stresses after impact. Different geometrical configurations which are likely to be encountered while designing such containers have been studied through plane 2D and 3D finite element analysis and the efficacy of this idea has been explored on each of them. Considerable reduction of stress has been reported and an explanation based on elastic deformation of layered beams has been suggested. Simulations on a cask with the currently prevalent design also show the benefit of implementing this idea.