Zirconia - A ceramic for excess weapons plutonium wastes

We synthesized a ceramic containing simulated excess weapons plutonium waste in solid solution with zirconia (ZrO(2))(5S). ZrO(2) has a large solubility for other metal oxides. More than twenty binary systems A(x)O(y)-ZrO(2) have been reported in the literature, including PuO(2), rare earth elements, and oxides of metals contained in weapons plutonium wastes. We show that significant amounts of gadolinium (neutron absorber) and yttrium (stabilizer of the cubic modification) can be dissolved in ZrO(2), together with plutonium (simulated by Th(4+), Ce(4+), or U(4+)) and impurities (e.g., Ca Mg, Fe, Si). Sol-gel and powder methods were applied to make homogeneous, single phase zirconia solid solutions. Pu waste impurities were completely dissolved in the solid solutions. In contrast to other phases, e.g., zirconolite and pyrochlore, yttrium stabilized cubic zirconia does not undergo amorphization upon irradiation.