Hydrophilic Chelators for Aqueous Reprocessing of Spent Nuclear Fuel

Significant improvements in aqueous reprocessing are a key need in closing the future nuclear fuel cycle and addressing concerns with past industrial reprocessing technologies. Despite much-dedicated efforts over the past several decades, the separation of the large variety of elements and isotopes, such as minor actinides, found in the fuel is unanimously challenging. This review summarizes and classifies various aqueous chelators that have already been implemented or could potentially be used in the aqueous reprocessing of spent nuclear fuel. A variety of processes are briefly introduced, and the application of aqueous chelators is analyzed, with a focus on the elements targeted for separations, as well as aqueous/organic phase composition and acidity, and inherent physico-chemical properties. Comparisons among these agents are made to provide a clear outline of their unique characteristics. Different aqueous chelators function in different ways and thus are applied with different purposes. However, there exist limitations, even for the most widely applied polyaminocarboxylate ligands, and functional groups have been relentlessly modified over the years to achieve more efficient, sustainable, and cost-effective separations.