Legal Weight Truck Cask Model Impact Limiter Response

Dynamic and quasi-static quarter-scale model testing was performed to supplement the analytical case presented in the Nuclear Assurance Corporation Legal Weight Truck (NAC LWT) cask transport licensing application. Four successive drop tests from 9.0 meters (30 feet) onto an unyielding surface and one 1.0-meter (40-inch) drop onto a scale mild steel pin 3.8 centimeters (1.5 inches) in diameter, corroborated the impact limiter design and structural analyses presented in the licensing application. Quantitative measurements, made during drop testing, support the impact limiter analyses. High- speed photography of the tests confirm that only a small amount of energy is elastically stored in the aluminum honeycomb and that oblique drop \"slapdown'' is not significant. The qualitative conclusion is that the limiter protected LWT cask will not sustain permanent structural damage and containment will be maintained, subsequent to a hypothetical accident, as shown by structural analyses. It should be noted that the model cask was fabricated using Type 304 stainless steel, which has a yield strength that is at least 50 percent lower than the Type XM-19 stainless steel the LWT cask is actually fabricated from. Three quasi-static impact limiter tests were performed to clearly demonstrate how the deceleration force develops as the impact limiter crushes. Quasi-static test forces, when corrected for dynamic crush strengthening, were less than or equal to calculated values. Quasi-static tests confirmed a shear force component of the total crush force. The shear force represents a smaller percentage of the total crush force in the full-scale impact limiter response because of the smaller shear area to backed crush area ratio. The quasi-static tests prove that the impact limiter design methodology is applicable and appropriate.