GA-4/GA-9 honeycomb impact limiter tests

General Atomics (GA) is under contract to the US Department of Energy, Field Office, Idaho, to develop two legal weight truck casks for transportation of spent nuclear fuel. This development project supports the Office of Civilian Radioactive Waste Management mission goal to develop a safe and efficient transportation system. The GA-4 and GA-9 Casks transport four pressurized-water-reactor (PWR) and nine boiling-water-reactor (BWR) spent fuel assemblies, respectively. The GA-4 and GA-9 Casks have similar designs. They both are long (the GA-9 is a little longer) and have square cross-sections with rounded corners. At each end is an aluminum honeycomb impact limiter to absorb energy and limit forces during impact. To evaluate the effectiveness of the impact limiters, GA performed a test program to obtain data on the behavior of the impact limiters over the range of impact angles. The test program was divided into three phases. Phase 1 provided the basis for understanding the behavior of honeycomb and the effects of structural backing, operating temperature and impact velocities on the honeycomb crush strength. Phase 2 provided data on the behavior of the complete impact limiter at different angles. Based on the results of Phase 1 and Phase 2 tests, the impact limiter design was optimized prior to commencing Phase 3. Phase 3 tested the final impact limiter design over a range of angles, providing a complete characterization of the impact limiter behavior. This paper discusses the test program, the test results, and how these helped optimize the impact limiter design. It emphasizes the results obtained during Phase 3 of the test program. The results obtained during Phases 1 and 2 were reported previously. This paper also includes a discussion on how the test results compare with analytical predictions