DEVELOPMENT OF NEUTRON ABSORBER (MAXUSTM) FOR HIGH BURN-UP SPENT NUCLEAR FUEL

B-AL (Boron-Aluminium) plate is commonly used as a neutron absorption material for the basket plate of casks. For material property reasons, the boron carbide content (boron weight %) of the B-AL plates is commonly in the 15-40wt% range. Recently canister-based systems have been developed for long-term storage (60 years to 100 years) of high burn-up fuel, requiring higher neutron absorption. However, increasing the boron carbide content of conventionally produced plates reduces their ductility and thermal conductivity, and increases their cost. Therefore a new neutron absorber material (MAXUS?) with higher content of boron carbide was developed. The mechanical and physical properties and corrosion resistance of MAXUS? plate containing 30-70wt% of natural boron carbide were measured. MAXUS? plate is produced using a powder metallurgy process. The plate has a sandwich structure with almost 100% dense MMC core and thin aluminum skins. The alloy skin improves the plate’s mechanical properties and anti-corrosion resistance, and bonding during sintering. The sintering process was optimized to prevent occurrence of blisters. After sintering, the plates were hot and cold rolled to assure uniformity of the materials. Test samples were prepared containing 30,40,50,60, and 70wt% natural boron carbide materials. Microstructure observations and mechanical, physical and corrosion testing have shown that the particles of boron carbide are distributed uniformly in MAXUS? plate. Anti-blister tests also showed strong resistance to blistering. It has also been verified that MAXUS? has reliable neutron absorption and mechanical and physical properties.