Abstract
Uranium in uranyl nitrate-TBP solution was converted into dioxide by vacuum distillation and ignition. In vacuum distillation, TBP and its diluent were recovered at 40°150°C in nitrogen stream under 15mmHg. The residue of distillation was incinerated in nitrogen stream with 0.11.0mmHg by raising the temperature from 400° to 1, 300°C. The final product is a black powder of UO2, identified by X-ray diffraction, by density measurement and by chemical analyses. Uranyl nitrate TBP solution is evolved during fuel reprocessing, and thus the vacuum distillation reported here could be applied to the solution in order to simplify the process.
