The pseudo binary phase diagrams of PuO 2 with alumina, beryllia and magnesia and the pseudo ternary PuO 2-ThO 2-BeO

Abstract

The pseudo-binary phase diagrams of plutonium oxide with alumina, beryllia and magnesia have been examined under oxidizing conditions. All three systems are simple eutectics with no intermediate compounds and limited terminal solid solubility. The compositions and temperatures of the eutectics have been determined: the latter are very similar to those reported for the corresponding urania systems. The system BeO-ThO 2 was also found to be a simple eutectic, in agreement with the results of previous workers. In the ternary system BeO-ThO 2-PuO 2, there is negligible solid solubility of beryllia in the plutonia-thoria solid solution and vice versa and a eutectic valley joins the eutectics in the binaries BeO-ThO 2 and BeO-PuO 2.