The extraction of cesium, strontium, and a number of stable components of simulated high-level waste solutions from nitric acid media with solutions of crown ether derivatives in new fluorinated diluents was studied. Based on the data on the solubility of the extractants into the aqueous phase and the physicochemical properties of the diluents used, the most promising extraction systems were chosen: crown ethers 4,4'(5')-di-tert-butyldibenzo-18-crown-6 (L1) and 4,4'(5')-di-tert-butyldicyclohexyl-18-crown-6 (L2) in bis(2,2,3,3-tetrafluoropropyl) carbonate (BK-1) and bis(2,2,3,3-tetrafluoropropoxy)methane (FN-1). For these systems, the extraction of a number of stable components and their subsequent stripping with water and solutions of chelating agents were studied. Lead was found to be co-extracted to the greatest extent. To a lesser extent, barium and calcium cations are co-extracted with strontium, and rubidium and potassium cations with cesium. Lead, barium, and silver are the most difficult to strip; however, the problem of lead stripping can be solved by using DTPA or citric acid solutions neutralized with ammonia to weakly alkaline (pH 8) media.

ABSTRACT New non-inflammable compounds – carbonates of fluorinated alcohols were proposed as potential diluents for tributyl phosphate (TBP). These compounds are commercially available, have high boiling point, high density, and low solubility in water solutions. Extraction of actinides from nitric acid by TBP solutions in fluorinated carbonates was studied. TBP solutions in fluorinated carbonates show lower extraction ability comparing with TBP solutions in hydrocarbon diluents. In spite of this, it is possible to extract more than 99.9% of tetra- and hexavalent actinides presented in spent nuclear fuel solutions. The advantage of proposed solvent is possibility to obtain uranium strip product with uranium concentration higher than 100 g/l.

As part of PRORYV project activities dynamic tests of extraction systems (CMPO - TBP - F-3, Dyp-7 - F-3, ATP - CCD - F-3 (UNEX-T) i TODGA - F-3) were carried out. With the use of TODGA - F-3 from raffinate of PUREXprocess from recycling of SNF WWER-440, the deep extraction of americium and curium was demonstrated (99,9% from the initial content). Using the concentrate of MA and heavy REE from recycling of SNF WWER-1000 experiments on chromatographic separation of americium and curium were carried out. The fractions of Am a purity of more than 99.9% was obtained. Mathematical models have been developed for all the processes studied, both for the process itself and for the operation. Verification of mathematical models on model and real products is planned.

Extraction of actinides from aqueous nitric acid by three different heterocyclic dicarboxamides (2,6-pyridinedicarboxamide, 2,2′-bipyridine-6,6′-dicarboxamide and 1,10-phenanthroline-2,9-dicarboxamides) was studied. It was shown that all studied ligands extract actinides at different oxidation states (U(VI), Np(V), Pu(IV), Am(III), Cm(III)) from acidic solutions. All studied diamides extract Am(III) better than Cm(III). Et(pHexPh)ClPhen contains electron-withdrawing chlorine atoms at the positions 4 and 7 of the phenanthroline moiety (SFAm/Cm = 4–6) and possesses the highest separation factor Am(III)/Cm(III). The studied ligands possess high extraction ability to all actinides present in HLW and therefore they could be used for simultaneous extraction of actinides in the GANEX-type process.

1,10-Phenanthroline-2,9-dicarboxamides of various structures were synthesized and studied as ligands for separation and sensing of d- and f-metals.