Status of FIPRED development

Full text: The paper present the results of the study of UO2 sintered pellets oxidation, part of FIPRED (Fission Product Release from Debris Bed) Project. The FIPRED Project is dedicated to the study the fission products release from irradiated pellets existing in debris bed. The product release is produced by oxidative self-disintegration of sintered pellets at air ingress and it is temperature dependent. The experimental program covered experiments of 30 deg. C -1000 deg.C in air diluted with nitrogen at different concentration of oxygen. The experiments were performed using the SETARAM thermo-gravimetric equipment and the FIPRED EQ equipment designed and manufactured especially for this type of experiment. The powders (fragments), resulted from UO2 pellets self-disintegration, were characterized by sieving and SEM. The self-disintegration mechanism was demonstrated using the experimental results obtained and thermodynamically data of uranium oxides. (authors)