Development of vol-oxidizer for oxidation of UO2 pellets, 20 kg HM/batch

Vol-oxidizer is a device to convert UO2 pellets into U3O8 powder and to feed a homogeneous powder into a Metal Conversion Reactor in the ACP(Advanced Spent Fuel Conditioning Process). In this study, we proposed a design model of the vol-oxidizer and developed the new vol-oxidizer with a capacity of 20 kg HM/batch in UO2 pellets. Design considerations include the internal structure, the capacity, the size, and the heating position of the device. The dimensions of the new vol-oxidizer are decided on by the design model. We conducted a permeability test of the U3O8, measured the temperature distribution, and the volume of UO2 and U3O8. We manufactured the new vol-oxidizer for a 20 kg HM/batch in UO2 pellets, and analyzed the characteristics of the U3O8 powder for a verification. The experimental results show that the oxidation time takes only 8 hours when compared with the 13 hours of the old device, the U3O8 powder wasn't scattered up to the air flow rate of 12 L/M, and the UO2 pellets were pulverized into the U3O8 with an average particle size of 40 μm. (author)