M.J.D. Rushton1, L.J. Evitts1, A.Claisse2, M.Puide2, W.E. Lee1, and S.C. Middleburgh1
2Westinghouse Electric Sweden Ltd.
Grain boundaries in UO₂ may become amorphous in nature, as additives migrate to the more favourable grain boundaries. Additives such as Cr₂O₃ and Al₂O₃ are initially added to the fuel to promote grain growth during sintering, increasing the burn-up of the fuel pellet. Other advantages of additives include reducing fission gas release and pellet-cladding mechanical interaction . The impacts of diffusion along amorphous doped UO₂ grain boundaries differ dependent on temperature, with low temperature diffusion (< 1200 °C) controlling the creep rate, and higher temperature diffusion (> 1200 °C) impacting grain interchanges, impurity diffusion, and grain boundary pinning . This work focuses on modelling the diffusivity of constituent species of Cr₂O₃ doped amorphous UO₂ at a range of concentrations and temperatures. Results from this work can provide a further understanding to amorphous doped UO₂ grain boundaries, and how additives have an impact on the mechanical properties of the fuel pellet.
 T. Matsuda, Y. Yuasa, S. Kobayashi, and M. Toba, “Characteristics of Fuel Pellet with Additive of Al and Si.” Nuclear Fuel Industries Ltd., Osaka.
 A. A. Solomon, C. S. Yust, and N. H. Packan, “Primary creep of UO₂ and the effect of amorphous grain boundary phases,” J. Nucl. Mater., vol. 110, no. 2–3, pp. 333–342, 1982, doi: 10.1016/0022-3115(82)90163-5.
Event Timeslots (1)
Wednesday – 15th September 2021