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.