Kinetics of initial stage of sintering of UO2 and UO2 with Nd2O3 addition

The kinetics of initial stage sintering of UO2 powder were reinvestigated, using Ar-10% H2 atmosphere. The effect of the addition of neodymium oxide was studied. The results revealed that surface and grain boundary diffusion mechanisms act simultaneously. The values of activation energies were found to be 48.48+-3.51 kcal/mole in the temperature range 870-9420C and 89.88+-9.87 kcal/mole in the temperature range of 942-10300C for UO2, and 115.61 +- 7.77 kcal/mole in the temperature range 1030-11500C for UO2+Nd2O3. An important decrease in the calculated diffusion coefficient occurs by the addition of Nd2O3. (Auth.)