乾式粉末化裝置를 利用한 UO₂ Pellet 酸化實驗 硏究

Abstract

The Advanced Spent Fuel Conditioning Process (ACP) converts spent fuels into the metallization which used the electrochemistry method within the medium of the Li smelting-salt, and there is a system which can reduce the volume of spent fuels, the caloric value, and an amount of radiation up to one-fourth by reducing high exothermic nuclide (Cs, Sr). In the first process of the ACP, the dry pulverizing process, UO₂ pellet is converted into U₃O_(8) powder since U₃O_(8) powder is much desirable form for the following metallization process. In this study, the optimal condition was examined by producing similarly the dry pulverizing device, after setting up three parameters (Air flow rate, Oxidation temperature, O₂ concentration). As a result of the oxidation experiments, it found that the optimal oxidation condition is at 500℃, 2000 cc, 21% of O₂ concentration. And U₃O_(8) powder obtained from the oxidation of UO₂ pellet has been verified for XRD (X-ray diffractometer) and TGA (Thermogravimetric analysis), and inquired to befit a particle size of U₃O_(8) powder. We tried to find the optimal condition of air flow rate, oxidation temperature, and O2 concentration, which provides the maximum oxidation rate and prevents scattering of the fine U₃O_(8) powder in the reactor caused by the excessive air flow rate, by using the small sized dry pulverizing device. It is expected to be applying basic data to huge amounts (20 kgHM/batch) of the vol-oxidation process in the ACP.