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Materials Science at Oregon State University

Nuclear Waste Disposal Issues

Date: Thursday, May 5th
Presenter: Alex Brown, PhD Candidate, OSU Nuclear Engineering and Radiaton Health Physics

Abstract


The Fuel Cycle Research and Development programme (FCRD) is focused on developing effective and economical means to reducing the volume, toxicity, and lifetime of irradiated nuclear fuel (INF). As part of the FCRD, partitioning and transmutation (P and T) would recycle long-lived actinides (An) into commercial reactors to be transmutated into lighter, shorter-lived nuclides. Therefore, the separation of minor trivalent actinides (An3+) from trivalent lanthanides (Ln3+) at an industrial scale is a critical and technical challenge in advanced liquid-liquid reprocessing of INF and closing the nuclear fuel cycle in the U.S.

Carboxylic acids have played an important role in the field of separating An and Ln using liquid-liquid extractions. Studies have now shown that negligent control of the oxalate concentration in liquid-liquid reprocessing of high-level waste can jeopardize the solubility of Ln and An. Recent bench-scale experiments have demonstrated that the more soluble 3-carboxy-3-hydroxypentanedioic acid (citric acid) is a propitious aqueous complexant that can effectively aid in the separation of transition metals from f-elements mixtures using a combined solvent mixture of di(2-ethylhexyl) phosphoric acid (HDEHP) and octyl(phenyl) - N’,N’,- diisobutylcarbamoylmethyl phosphine oxide (CMPO).