Feasibility study for scaling ferritic spent fuel casks for drop tests

Within appropriate constraints, scale-model drop testing for demonstrating cask integrity is technically and practically feasible. Structural response and potential for crack initiation (fracture toughness) can be scaled. The flaw sizes assumed in this scaling analysis are a significant proportion of the cask wall thickness. The minimum depth considered was one-tenth the wall thickness. Detection of such flaw sizes are well within the capability of conventional NDE. The stress values analytically calculated are believed to realistically represent those a cask would experience in a 9-meter side-drop. Since this first phase of the EPRI/Sandia TTC cask scaling program analytically demonstrated the feasibility for scaling, it remains to actually drop test a properly instrumented scale model cask to experimentally demonstrate the approach. This model cask should have a defect machined into the highest stress location. The full-size cask should be analytically characterized prior to drop testing the model. Ideally, a drop test would eventually be conducted on the prototype to confirm the scaling concept. In addition to demonstrating the scaling concept, a successful drop test of a cask, be it model or prototype, would also demonstrate the potential of a linear-elastic fracture mechanics approach for ensuring structural integrity. 7 references, 3 figures