Marion Le Guellec, Florent Lebreton, Laure Ramond, Philippe Martin, Abibatou Ndiaye, Thierry Gervais, Guillaume Bernard-Granger
The grain size distribution of an U0.89Pu0.11O2 MOX fuel, sintered from a freeze-granulated powder to 97% of the theoretical density at 1700 °C during 4 h, for an oxygen potential set to − 387 kJ/mol, was investigated. The sintered microstructure is constituted by 8.5 vol% of clusters of small grains, having an average grain size around 1.5 µm, dispersed in a polycristalline matrix made of larger grains having an average grain size around 7–8 µm. Characterizations by Raman micro-spectroscopy showed that the Pu/(U+Pu) content was not the same depending on the type of grain. The large grains constituting the sintered polycrystalline matrix have a Pu/(U+Pu) content in the range 9.0–11.0 mol%, which is close to the overall target. The small grains agglutinated in the form of clusters are however clearly depleted in Pu.
Microstructure, Grain size, Raman spectroscopy, MOX