A Study of the Factors Influencing the Sinterability of Uranium Dioxide

Abstract

It was shown earlier that uranium dioxide derived from different compounds exhibited variations in the sintering behaviour and to attain maximum densification, the sintering should be carried out within a temperature range, specific for each of the powders.In the present work, the sintering behaviour of uranium dioxide derived from ammonium diuranate prepared by different methods, was studied in an atmosphere of hydrogen. Significant differences in the sintering (densification) behaviour of the powders was noted under identical sintering (firing) treatments. The influence of variations in sintering treatment, such as rates of heating or soaking periods, on the densification of the samples of different origins was studied. It was found that the sintering behaviour depended on both the powder characteristics and the sintering treatment. Attempts were made to relate the origin and thermal history of the UO2 with its powder characteristics; and its sintering behaviour to its powder characteristics and the firing treatments. Pellets of high density and controlled microstructure can be prepared from urania powders of varying characteristics, if firing treatments, avoiding pore entrapment during any stage of sintering, are evolved for each of the powders.