Density decrease of oxidatively sintered UO2–5wt%CeO2 pellets during resintering in H2 atmosphere

Pellets admixed with zinc stearate showed density decrease of 3%T.D. during resintering in H2 atmosphere, but density change was below 0.4%T.D. in the pellets admixed with Acrawax and stearic acid when all the powder compacts were sintered in CO2 atmosphere. Experiments revealed that the density of the pellets doped with zinc compounds and sintered in CO2 also displayed a density decrease of 3%T.D. after resintering. Therefore, it was considered that the major cause of the large swelling of the pellets sintered in CO2 atmosphere after resintering was Zn residues.