Evaluation of the impacts of gamma radiolysis on an ALSEP process solvent

Separating the minor actinide elements (americium and curium) from the fission product lanthanides is an important step in closing the nuclear fuel cycle. Isolating the minor actinides will allow transmuting them to short lived or stable isotopes in fast reactors, thereby reducing the long-term hazard associated with these elements. The Actinide Lanthanide Separation Process (ALSEP) is being developed by the DOE-NE Material Recovery and Waste Form Development Campaign. The impact of gamma radiolysis upon the efficacy of the ALSEP process was previously evaluated by determining americium, europium, and cerium distribution ratios as a function of absorbed dose using samples taken from this set of test loop irradiations. The measured distribution ratios demonstrated that the ALSEP solvent performance was degraded by γ-irradiation. The compositional analysis of the irradiated ALSEP solvent samples revealed that the decrease in americium, europium, and cerium distribution ratio with increasing absorbed dose is primarily attributable to the loss of the T2EHDGA extractant due to radiolytic degradation.