Trivalent Actinide and Lanthanide Separations Using Extraction Chromatography

Jennifer Shusterman, University of California, Berkeley

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The effective separation of trivalent actinides and lanthanides is one of the key steps in partitioning spent nuclear fuel and legacy waste for better stewardship of these materials. Thus far the process has been hindered by the chemical and physical similarities of these elements. I have explored the separation properties of the DGA (N,N,N’,N’-tetra-n-octyldiglycolamide) extraction chromatography resin for this application. Although the trivalent actinides and lanthanides are similar in most respects, they do exhibit slightly different complexation behavior with the DGA ligand in acidic media, making the resin a promising choice for successful procedures. Both hydrochloric and nitric acid of varying concentrations have been explored as eluents to determine the role of the acid in binding and the cause of the binding differences. Based on these differences in complexation, I have designed a procedure to separate Eu(III), Am(III), and Cm(III) from La(III), and have achieved successful separations of all three metals from the La(III). Experiments are currently being conducted for a separation of Eu(III) from Am(III), a process that directly models the fuel processing stage to remove trivalent actinides from trivalent lanthanides, which are some of the heavy fission products present in the spent fuel. In parallel, I am developing a separation of Cm(III) from Am(III) as a final partitioning stage for the trivalent actinides.

Abstract Author(s): J. A. Shusterman and H. Nitsche