High Conversion Th-U233 fuel for current generation of PWRs: Part III - Fuel availability and utilization considerations

In the previous studies, reported in Parts I and II of the paper, a High Conversion (HC) Th-U233 fuel design for current generation of PWRs was proposed and investigated in details on a single fuel assembly and 3D full core levels. One of the important limitations of the previous studies was the reliance on the availability of pure U233 as a fissile driver. In reality however, U233 will always be accompanied by other U isotopes with changing relative fractions until equilibrium is reached. Part III of the paper deals with a number of fuel cycle aspects associated with the use of HC Th-U fuel in PWRs including: (1) More realistic estimation of neutronic characteristics and conversion performance of HC Th-U fuel by accounting for the evolution of U isotopic composition with the number of recycle stages; (2) Reassessment of the HC Th-U PWR core performance through 3D full core coupled neutronic and T-H analysis using the equilibrium Uranium isotopic vector; (3) Demonstration of a feasible way of generating U233; (4) Evaluation of potential savings in available resources that can be achieved by using HC Th-U fuel cycle as compared to the current fuel cycle practices. The obtained results imply that the self-sustainable mode of operation for the proposed HC Th-U fuel assembly design cannot be achieved under the specified fuel cycle length constraint when a realistic U vector is taken into account in the analysis. Nevertheless, the introduction of HC Th-U fuel cycle can notably improve the utilization of available resources.