Dr. Brian J. Jaques
As world electricity demands increase, nuclear energy can be a consistent, carbon-free energy source. This elicits a need to improve reliability and efficiency of nuclear fuels, which requires an understanding of physical and chemical fuel/cladding interactions. In the uranium dioxide (UO2)-zircaloy cladding system currently used in US light water reactors, fission gas released via grain boundary diffusion into the fuel-cladding gap behaves as a neutron poison and reduces thermal conductivity. This ultimately impacts fuel efficiency and reliability. Due to their common fluorite crystal structure and similar thermophysical properties, cerium dioxide (CeO2) was used as a surrogate for UO2 fuel to reduce the challenges of working with radioactive materials. Pure and 0.1 - 5 wt% manganese dioxide (MnO2)-doped CeO2 samples were synthesized and characterized for chemical homogeneity and grain morphology since increased grain size leads to improved fission product retention. Scanning electron microscopy images were used to analyze microstructure, while x-ray diffraction, non-dispersive infrared spectroscopy, and energy dispersive spectroscopy were used to investigate phase, stoichiometry, and the incorporation of Mn+ into the CeO2 lattice. Preliminary results of pure and 0.25wt% MnO2-doped CeO2 respectively had theoretical densities of 97±2% and 95±2% and average grain sizes of 22-26µm and 13-15µm.
Winters, Riley C.; Doyle, Cayden; Lupercio, Adrianna E.; Nelson, Andrew T.; and Jaques, Brian J., "Effects of Oxide Additives on the Microstructure of Surrogate Nuclear Fuels" (2020). 2020 Undergraduate Research Showcase. 204.