Fission Gas Release from Uranium Heated in Carbon Dioxide

An experiment to predict the amount of fission gas release from U heated in CO₂ was made in connection with the safely evaluation of the Tokai Atomic Power Reactor. Fission gas release from slightly irradiated U pieces was measured as a function of percent oxidation, and it was found that the percent release was proportional to the percent oxidation. The fission gas released before the U was completely oxidized was 11%, 23% and 48% at 500°, 600° and 700°C, respectively. The form of temperature dependence of the fission gas release was of the Arrhenius type, with an activation energy of 5.1kcal/mol.