Thermal behaviour of caesium implanted in UO2: A comparative study with the xenon behaviour

Xenon and caesium are among the most impacting fission products when studying nuclear fuel: xenon for its role on fuel rod thermomechanical behaviour during reactor operation in case of atmospheric radioactive release an accident a power plant. This paper focuses comparison thermal polycrystalline uranium dioxide (UO2) pellets. Caesium-133 or xenon-136 stable isotopes were introduced depleted UO2 samples by ion implantation at maximum concentration 0.08 at% depth around 140 nm below sample surface. Annealing under reducing atmosphere (Ar/H2 5 %) was performed 1000 °C 1600 °C, which corresponds respectively to representative temperature (at centre pellets) accident. The migration investigated Secondary Ion Mass Spectrometry compared °C. Transmission Electron Microscopy order characterise microstructure before after annealing. results indicate that has different than with it is often from fuel. In particular, we highlight difference between growth kinetics bubbles can be correlated availability vacancies ability Xe Cs atoms resolution.