Recycling of Uranium in Process of Preparation UO₂ Kernels by Sol-Gel Method

This report describes the various waste generated in the preparation process of UO₂ kernels for HTGR fuel elements by sol-gel method in Institute of Nuclear and New Energy Technology (INET), Tsinghua University. The U-containing liquid waste could be firstly precipitated by a strong alkaline. It is crucial that the precipitate must be treated through calcination-reduction-calcination such that recovered U₃O₈ powders can be used effectively; otherwise, if the precipitate was directly calcined to U₃O₈, the U₃O₈ powders would have poor solubility. UO₂ microspheres that do not meet the technical specifications and treated as not acceptable in quality could be calcined directly and U₃O₈ powders thus obtained could be used satisfactorily. The U₃O₈ recycled from those wastes can be reused as raw materials to produce UO₂ kernels meeting the technical requirements. The overall U recovery yield is 99.98%.