2003 Volume 52 Issue 6 Pages 299-307
Pyrochemical reprocessing using molten salts (RIAR process) has been recently developed for recovering UO2 from spent nuclear oxide fuel. It is essential to improve the corrosion resistance of equipments such as electrolyzer because the process includes severe corrosion environment.
In this study, the corrosion resistance of ceramic materials was discussed through the thermodynamic calculation and corrosion test. The corrosion test was basically carried out by reacting ceramic specimens with alkali molten salt under chlorine gas. In addition, the effects of oxygen, carbon and major fission product's chlorides on ceramics corrosion were evaluated in molten salt under chlorine gas.
In eleven kinds of ceramic materials, silicon nitride, mullite and cordierite had a good corrosion resistance which was 0.1mm/y or less in above conditions. Cracks on the materials were not observed and bending strength did not drop remarkably after corrosion test of 480h in molten salt under Cl2-O2 bubbling conditions. These ceramic materials are promising to apply to the RIAR process.