Kinetics of and atmospheric effects on gallium removal from a CeO{sub 2} based mixed oxide surrogate

This paper describes preliminary experimental results on the kinetics of Ga removal from Ga{sub 2}O{sub 3}-doped CeO{sub 2{minus}x}, a surrogate for weapons grade PuO{sub 2{minus}x}. Ga is removed from the surrogate feedstock material using thermal techniques. An Ar-6% H{sub 2} gas was used in order to reduce the oxide to gaseous Ga{sub 2}O. Experiments were done in the temperature range of 600--1,200 C as a function of time, gas flow rate, and sample geometry. Samples were analyzed through measurements of weight change, scanning electron microscopy/energy dispersive spectroscopy, x-ray photoelectron spectroscopy, proton induced x-ray emission, and direct current plasma analysis. Gallium levels were reduced by as much as 98% (130 ppm Ga residue) of that in the starting material. Studies to date have shown CeO{sub 2{minus}x} is a very good surrogate for PuO{sub 2{minus}x}