COSANs

COSANs- solvent extraction reagents for the separation of radionuclides from waste solutions

Throughout the world a great effort has been devoted to proposing safe storage of radioactive wastes in permanent repositories. The risk of container burst or uncontrolled leakage of corroded containers etc. would be minimized when the volume of the stored wastes is reduced or the waste is classified. For such cases, a preliminary separation of radionuclides is essential.

COSAN   -   is Solvent Extraction Reagent [SER] for separation and isolation of     ¹³⁵Cs,
¹³⁷Cs and ⁹⁰Sr nuclides, the intensive sources of gamma, respective beta radiation. The nuclides cannot be extracted from the High Level Wastes (HLW) dissolved in strong nitric acid by various organic SER because those are quickly deteriorated under the severe condition. Consequently, special SER have to be applied, e.g. chemically and radiation stable hydrophobic anions.

Prominent among them are various derivatives of Cobaltocarborane Sandwich Anion, COSAN, which is trivial name of Cesium bis(1,2-dicarbollide) cobaltate, Cs⁺[Co(C₂B₉H₁₁)₂]^-. This compound is the salt of extremely hydrophobic anion, the important properties of which are high solubility in organic solvents, high chemical and radiation stability, and a complete dissociation of its salt in all solutions. The extraction of radionuclides with COSAN is usually carried out with nitrobenzene, but other solvents such as dichloroethane, etc., might be applied as well. The technology allows reducing the hazard of the processed wastes. COSAN can also be exploited for the extraction of Ba and Ra nuclides as well as for trivalent lanthanides and actinides. In several cases, COSAN has also been exploited as a carrier electrolyte for organic solutions.

Hexachlorinated or hexabrominated COSAN is even more resistant to warm concentrated nitric acid and intensive radiation - that is the medium of radionuclide extraction from the solution obtained by dissolution of used nuclear power plant cells. Katchem also produces both.

COSANs research proceeded also during solving project EUROPART (EUROpean Research Programme for the PARTitioning of Minor Actinides) in the 6. Framework Program, from which the project was cofinancing.

Contact person:

Bohuslav Čásenský, Ph.D.,casensky@katchem.cz, Phone: +420 266 173 148