Keywords: advanced heavy water reactor, AHWR, nuclear reprocessing, spent fuel, thorium, plutonium, uranium 233, purex, thorex, pulsed columns, solvent extraction, process modelling, simulation, nuclear reactors, nuclear power, nuclear energy, nuclear safety, nuclear fuel cycle
Reprocessing of AHWR spent-fuel: challenges and strategies
Reprocessing of advanced heavy water reactor (AHWR) spent-fuel involves separation of Th, 233U and Pu, from the fission products and from one another. A proper combination of Purex and Thorex processes is required. The technology development for a reprocessing facility is extremely complex owing to high fissile content, high levels of irradiation, presence high of levels of 232U, difficulty in thoria dissolution, presence of thorium as the major constituent, problems due to third phase formation with Th, etc. It demands for development of suitable dissolution, solvent extraction, criticality control, U-Pu partitioning, and other equipments and/or techniques. Process modelling, simulation and optimisation are crucial in predicting behaviour of equipments/cycles, and in arriving at safe and optimum flowsheet. A significant success in this field has been achieved. This paper describes the reprocessing aspects pertaining to AHWR spent-fuel, indicating the major technological challenges, strategies to be followed and development requirements. A schematic flowsheet is proposed for Th-233U-Pu separation.