Uranium/technetium separation for the UREX process – synthesis and characterization of solid reprocessing forms

In the context of the demonstration of the UREX (uranium extraction) process, a separation of uranium and technetium using an anion exchange resin was performed on a simulant solution containing 98.95 g/L of238U and 130.2 mg/L of99Tc. After sorption on the resin, TcO4−was eluted with NH4OH, the eluting stream was treated, and the technetium converted to Tc metal (yield=52.5%). The purity of the compound was analyzed: it contains less than 23.8 μg of238U per gram of99Tc. Tc metal was characterized by X-ray diffraction (XRD) and X-ray absorption fine structure (XAFS) spectroscopy; EXAFS analysis clearly confirms the hexagonal structure of the metal obtained after treatment. Uranium was converted to ammonium diuranate and to U3O8in a yield of 88.2%, analysis indicates that the compound contains less than 0.16 μg of99Tc per gram of ammonium diuaranate.