Development of an emulsion flow technique for uranium extraction and sludge removal

Okamura, Hiroyuki   ; Nagano, Tetsushi  ; Naganawa, Hirochika  

A centrifugal contactor has been investigated as a promising extractor in the separation and purification process based on solvent extraction in the nuclear fuel reprocessing. However, there is a problem of being affected by sludge components such as undissolved residues. The emulsion flow method is based on the control of the generation and disappearance of a flow in an emulsified state in which an aqueous phase and an oil phase are mixed, and can actualize highly efficient and rapid solvent extraction. Therefore, this method has attracted much attention as an innovative technique. In this study, to develop innovative reprocessing technology for spent nuclear fuels by the emulsion flow method, we constructed a system integrating highly efficient solvent extraction of uranium and removal of sludge components from a nitric acid aqueous solution simulating reprocessing process. It was demonstrated that, by using the emulsion flow apparatus, uranium can be selectively extracted and back-extracted from the simulated solution for nuclear fuel reprocessing without being affected by sludge components, and part of sludge components can be removed.