Spent nuclear fuel consists of four primary categories of waste: short-lived isotopes from neutron capture, short-lived fission products, long-lived actinides, and long-lived fission products. Of these, the long-lived actinides are particularly difficult to separate from the shorter-lived lanthanide fission products. Yet the isolation of the minor actinides from the lanthanides significantly reduces the radiotoxicity and heat-load of long-lived nuclear waste and also allows transmutation of the actinides to isotopes with shorter half-lives. Alternatives to the TALSPEAK process for the selective separation of minor actinides, particularly americium and curium, from lanthanides in actual spent fuel are being investigated. Separation of americium from curium is also of high interest for transmutation of americium and potential recovery of heavy curium.Compounds with selectivity for americium and curium under conditions relevant to the nuclear fuel cycle (i.e. nitric acid media containing light lanthanides through gadolinium in quantities about 10 times greater than those of minor actinides) are pyridine-based receptors. The nitrogen-based BTP/BTBP/BTPhen ligands are desirable for both separation ability and for being incinerable, and can remove pH control and aqueous complexants from the extraction process requirements. The presentation will highlight several ligands in this class that were analyzed for their respective stability, solubility in Cs-7SB/Isopar L, and separation ability. Study of the impact of the addition of tetraethyl diglycolamide as an aqueous complexant showed that such a liquid/liquid system could lead to improvement in the observed americium/curium separation factor.

Separation of americium from curium and trivalent lanthanides using pyridine-based receptors

245th National Meeting (2013)

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