UO2 Oxidation in Air or Steam-Release or Retention of the 49 Fission Products Ru, Ba, Ce, Eu, Sb and Nb

Abstract

The release of fission products from irradiated U02 has been studied under both inert (argon) and oxidizing (air and steam) conditions at temperatures up to about 1600 degrees C. The microstructures resulting from post-irradiation annealing and oxidation are presented and the release and retention of some of the metallic fission products are documented. Ruthenium and antimony are the main metallic elements which are released and ruthenium is only released in the presence of oxygen. Cerium, because of its low energy gamma-ray provides an excellent indicator of density changes in the fuel during oxidation.