Complexants fsro Actinide Element Coordination & Immobilization

The goal of this project is to develop inorganic metal oxide clusters known as polyoxoanions (POAs) as complexants for the immobilization of actinide (An) ions from high-level waste (HLW). A diverse array of rugged isopolyoxoanions, [MxOy]z- , and heteropolyoxoanions, [XaMbOc]d-, comprised of M = V, Nb, Mo, W and X = Si, P polyhedra are under investigation for their ability to incarcerate An ions. The research combines two objectives-An-POA coordination and An-POA containment. The first involves the synthesis, isolation, and characterization of POAs that can selectively bind An ions to form stable An-POA complexes in alkaline and acidic solutions. The second involves investigations of the thermochemistry of the An-POA complexes under vitrification conditions germane to the formation of proposed HLW forms, such as borosilicate glass. The approach is envisioned to provide two levels of An encapsulation for maximum stability and durability as well as the potential to incorporate higher levels of An ions (particularly Pu) in waste forms than now possible. Such versatility bodes well for prospective applications of POAs as An complexants in technology of significance to the environmental management of HLW