Recovery of minor actinides from high-level wastes: modern trends

One of the major problems of nuclear power industry is associated with large amounts of radioactive wastes. Contemporary reprocessing technologies of spent nuclear fuel generate significant volumes of liquid high-level wastes, containing a great number of various nuclides. At present, fractionation is agreed to be the most promising and environmentally safe strategy of treating such wastes; however, this raises the problem of partitioning of minor actinides and lanthanides. Counter-current extraction in two-phase aqueous solution–organic phase systems is considered as the most efficient approach. Analysis of the extractant systems proposed to date, including systems with non-selective extractants (phosphine oxides, phosphoric acids, diamides of dicarboxylic acids, etc.) for joint recovery of lanthaniedes and actinides and systems with selective extractants (sulfur-containing compounds, $\mathrm N$-heterocyclic compounds, diamides of $\mathrm N$-heterocyclic dicarboxylic acids, etc.) for partitioning of actinides and lanthanides is presented. Modification methods for the known extractant systems, particularly the role of diluents, is discussed. The application of water-soluble complexing agents selective to actinides, including the possibility of combining extractants with complexants with opposite affinities, is considered.
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