Synthesis and characterization of zirconia-magnesia inert matrix fuel: Ce homolog studies

X-ray powder diffraction, microscopy, thermal analysis and electron probe microanalysis were used to characterize a ZrO2-MgO inert matrix containing CeO2 as a homolog for PuO2 and Er2O3 as a burnable poison. The synthesis was carried out using a precipitation method. A large composition range of MgO to ZrO2 was evaluated to determine phases present, phase mixing, phase composition, microstructure and thermal properties. It was found that most compositions of the material consist of two phases: MgO (periclase) and ZrO2 (cubic zirconia). The zirconia phase incorporates 5% (wt/wt) MgO and up to 14% and 12% (wt/wt) CeO2 and Er2O3, respectively. The MgO phase remains pure, which will enable it to retain its heat transfer and solubility properties and will improve the overall thermal conductivity and reprocessing component of the inert matrix fuel. The results with Ce will be used as the basis of future studies with actinides.