ALTERNATIVES OF HOMOGENEOUS THORIUM-URANIUM FUEL CYCLE UTILIZATIONS FOR PWR

The homogeneous mixture of thorium oxide with uranium oxide is an option to utilize thorium-based fuel for current existing PWRs without any mechanical modification of fuel assembly design. The fuel cost analysis for the core fully loaded with homogeneous thorium-uranium fuel, however, has shown no distictive economic advantage over UO2 fuel. Thus alternatives of homogeneous thorium-uranium fuel, have been investigated in order to enhance the economic potential of thorium cycle for PWR; 1) the thorium-uranium fuel with a relatively lower U-235 enrichment than 19.5w/o, 2) the mixed core of thorium-uranium and UO2 fuels, and 3) the use of homogeneous thorium-uranium fuel as radial reflector. The proposed alternatives result in far better fuel economics compared to the homogeneous thorium-uranium fuel cycle, but are still less economical than uranium fuel option.