Résumé
Abstract Homogeneous and heterogeneous U 1-x Ce x O 2 (with 0≤ x≤ 0.25) materials were prepared via wet and dry chemistry routes, respectively before being submitted to dynamic leaching experiments. The feeding solution containing 0.20 mmol.L −1 H 2 O 2 was kept under air and renewed to guarantee the stability of H 2 O 2 during the experiment. Normalized alteration rates were determined from U concentration in the leachates. For homogeneous (U,Ce)O 2 materials, the dissolution rate was divided by a factor of 3 when increasing the Ce content from 0.08 to 0.25. Surface characterizations revealed that studtite precipitated all over UO 2 pellet surface and only on the UO 2 grains of heterogeneous U 0.92 Ce 0.08 O 2 samples. The behaviour of this heterogeneous material was similar to that observed for (U,Pu)O 2 in the same conditions, which revealed the reliability of cerium as a plutonium analogue.