Role of diluents in thermal degradation of irradiated tri-n-butyl phosphate with nitric acid

The solvent extraction process using tri-n-butyl phosphate (TBP) as an extractant-the Purex process-has been widely employed in the recycling of irradiated nuclear fuel. This process is different from conventional solvent extraction in its being an operation under high radiation dosage. The study has been focused on the thermal degradation of irradiated diluents with HNO₃. ARC studies reveal that n-dodecane exothermically reacts with HNO₃ at 140°C to enhance the red-oil formation reaction. Thermo-kinetic studies of the mixture define the intrinsic safety parameters of the plant