The UO2 ceramic microspheres are the most important materials in the spherical fuel elements for high temperature reactor (HTR). A process for preparation of UO2 kernels known as total gelation process of uranium (TGU...The UO2 ceramic microspheres are the most important materials in the spherical fuel elements for high temperature reactor (HTR). A process for preparation of UO2 kernels known as total gelation process of uranium (TGU) was developed as the production process of 10 mW HTR at Tsinghua University. The TGU process is based on the traditional sol-gel process, external gelation process and internal gelation process of uranium (EGU and IGU), which implies that the gelation action is initiated both by ammonia out of the gel particles and hemxamethyl tetra-amine (HMTA) inside the gel particles. The gelation behavior and the properties of uranium microspheres were investigated of the solution with and without HMTA. It is observed that good spherical particles can be obtained without HMTA in the sol, which indicates a more controllable and industrialized route will be set up. Contrasts between this route and the traditional EGU were also listed.展开更多
This paper presents the process flow sheet of the main nuclear industrial units in Brazil and discusses some solvent extraction technical support required for these plants. The Center for the Development of Nuclear Te...This paper presents the process flow sheet of the main nuclear industrial units in Brazil and discusses some solvent extraction technical support required for these plants. The Center for the Development of Nuclear Technology-CDTN has been investigating alternative ways to supply the nuclear industry in order to improve the industrial processes, Some case study examples are presented, Emulsion from Uranium Solvent Extraction Plant and Itataia Uranium Developments. In Caitité industrial plant the water recirculation has caused continuous changes in the composition of pregnant liquor mainly in the sulfate and chloride concentrations. After some water recirculation cycles, a decrease in the uranium extraction efficiency was noted which was followed by the formation of stable emulsion at the uranium extraction stage. Itataia Uranium Developments were performed in a pilot plant for Itataia ore. This ore has the uranium mineral associated to the phosphate. The process consists of four main steps： 1） phosphate concentration, 2） chemical digestion of the concentrate to produce phosphoric acid with dissolved uranium, 3） uranium recovery, and 4） phosphoric acid purification by solvent extraction.展开更多
文摘The UO2 ceramic microspheres are the most important materials in the spherical fuel elements for high temperature reactor (HTR). A process for preparation of UO2 kernels known as total gelation process of uranium (TGU) was developed as the production process of 10 mW HTR at Tsinghua University. The TGU process is based on the traditional sol-gel process, external gelation process and internal gelation process of uranium (EGU and IGU), which implies that the gelation action is initiated both by ammonia out of the gel particles and hemxamethyl tetra-amine (HMTA) inside the gel particles. The gelation behavior and the properties of uranium microspheres were investigated of the solution with and without HMTA. It is observed that good spherical particles can be obtained without HMTA in the sol, which indicates a more controllable and industrialized route will be set up. Contrasts between this route and the traditional EGU were also listed.
文摘This paper presents the process flow sheet of the main nuclear industrial units in Brazil and discusses some solvent extraction technical support required for these plants. The Center for the Development of Nuclear Technology-CDTN has been investigating alternative ways to supply the nuclear industry in order to improve the industrial processes, Some case study examples are presented, Emulsion from Uranium Solvent Extraction Plant and Itataia Uranium Developments. In Caitité industrial plant the water recirculation has caused continuous changes in the composition of pregnant liquor mainly in the sulfate and chloride concentrations. After some water recirculation cycles, a decrease in the uranium extraction efficiency was noted which was followed by the formation of stable emulsion at the uranium extraction stage. Itataia Uranium Developments were performed in a pilot plant for Itataia ore. This ore has the uranium mineral associated to the phosphate. The process consists of four main steps： 1） phosphate concentration, 2） chemical digestion of the concentrate to produce phosphoric acid with dissolved uranium, 3） uranium recovery, and 4） phosphoric acid purification by solvent extraction.
