Raman/SEM chemical imaging of a residual gallium phase in a mixed oxide feed surrogate

An integrated analytical approach, which combines elemental [scanning elect ron microscopy with energy-dispersive X-ray spectroscopy (SEM/EDS)] and mol ecular (Raman) chemical imaging techniques, has been utilized for the chara cterization of a residual phase of gallium in mixed oxide (MOX) surrogate m aterial. Surrogate MOX materials are comprised of CeO2 in place of PuO2. In real MOX materials, PuO2 is mixed with UO2 as a commercial fuel source. A Ga phase remains in the surrogate sample following reductive heating experi ments designed to explore the removal of gallium from weapons-grade plutoni um. The SEM/EDS data reveal the concentration of Ga within the grain bounda ries of the sample and a distribution of Ce and O throughout the sample mat rix. Molecular analysis provided by Raman chemical matrix imaging correlate s with the SEM/EDS elemental imaging results. Specifically, the Raman data suggest that the matrix is comprised of CeO2 and grain boundaries are a mix ed phase comprised of CeO2 with a form of Ga, most likely a CeGaO3 perovski te phase ha,iug a cubic structure.