Manufacturing process of UO2 pellets

To perform the localization project of WOLSUNG reactor fuel, mass-production system of irradiation-stable and sound fuel pellet must be established. The following subjects have been carried out to set up CANDU fuel fabrication process for continuous production. The UO2 powder from AUC process was mixed with 0,5,10 and 15 W/O of U3O8, and directly pelletized without granulation process by the pressures of 0.8,2.1,2.8,3.0, and 3.6 t/cm2. Density and microstructure of the pellet were measured after sintered at 17000C in hydrogen atmosphere. The UO2 powder was pelletized with different dies and punches, and the cause of pelletizing failure is described in respect to the shapes of dies and punches. To finish centerless grinding by one pass, the diameter of new designed die nib is changed from 15.20 mm to 14.91 mm. The cause of UO2 loss and improving method to minimize the UO2 loss at each process are described