STUDY OF BINARY OXIDES OF URANIUM AND RARE-EARTH ELEMENTS
FOREIGN TECHNOLOGY DIV WRIGHT-PATTERSON AFB OH
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The formation of fluorite-type phases was investigated in R2O3-U3O8- O2 systems where R-La, Sm, Dy, Yb annealed for 66-85 hr at 1200C, and the solubility limits of the rare earth oxides in uranium octoxide were determined. The UVI content and the total uranium content were determined by coulometric analysis at a controlled potential. X-ray phase analysis was carried out by using the powder method with RKD-57 and RKU-86 cameras. The degree of oxidation of uranium changes with the ratio RU and reaches 6 in samples where RU21. Thus, the presence of a rare earth oxide increases the stability of the hexavalent state of uranium at high temperatures. Contrary to expectations, the solubility of rare earth oxides in U3O8 was found to be very low less than 1.5 mol of RO1.5.
- Physical Chemistry
- Fission Reactor Materials