Development status of the GA-4 and GA-9 casks

This paper reports that General Atomics (GA) has developed two legal-weight truck spent fuel shipping casks for transporting commercial reactor spent fuel. The GA-4 Cask carries four pressurized-water reactor (PWR) assemblies, and the GA-9 Cask carries nine boiling-water reactor (BWR) assemblies. Depleted uranium and a borated polymer are the gamma and neutron shielding materials. Type XM-19 stainless steel is the structural material used for the cask body, closure and the structure which supports the fuel assemblies. The impact limiters are made of aluminum honeycomb. Solid boron carbide, contained in the removable fuel support structure, provides poison for criticality control. The GA-4 Cask uses burnup credit to maintain criticality safety with spent fuel assemblies having enrichments greater than 3 wt% U-235. Ga has conducted an extensive test program for the neutron shield material and the aluminum honeycomb impact limiters