The compressive creep behavior of (U, Ce)O2

The effects of the CeO2 content (3.25 and 5 wt%), density (95-98% T.D.), grain size and dopant additions (SiO2, 0.005 wt%; Li2O, 0.1 wt%) on the creep behavior of the UO2-CeO2 sintered pellet have been investigated. Stress exponent, n, derived from the stress-creep rate relationship shows two values depending on the stress applied. One is n = 0.97-2.26 in the lower stress region, and the other is 3.40-8.90 in the higher stress region in the experimental ranges of this study. It is noted that the former is controlled by a diffusion process, and the latter is controlled by a dislocation motion mechanism. The activation energy for the creep increased as the CeO2 content increased.