Abstract:
The goal of Advanced Fuel Cycle Initiative program is to efficiently separate and recover actinides in attempts to reprocess irradiated nuclear fuel and reduce the necessary storage volume. In order to facilitate large-scale industrial
applications of liquid-liquid separation processes, knowledge of the thermodynamic constants associated with the distribution of metal ions between immiscible media is necessary. The influence of temperature on the extraction of Pu(IV) into 30 vol.% trin-butyl phosphate in n-dodecane from acidic nitrate solutions has been investigated at temperatures ranging from T = (294 to 313) K. Temperature was found to decrease the distribution of Pu(IV). Three species of plutonium were considered present in the aqueous solution: Pu⁴⁺, Pu(NO₃)³⁺ and Pu(NO₃)₂²⁺. The enthalpy and entropy of the extraction, calculated using Van't Hoff plots, are -60.4 ± 3.3 kJ·mol⁻¹ and -120 ± 10 J·mol⁻¹·K⁻¹, respectively.
