Date of Award
Master of Science
Uranium trioxide (UO3) is a stable uranium oxide found throughout the nuclear fuel cycle. The Î³-UO3 phase is of particular interest as the most stable at ambient conditions. As such, the Î³-UO3 structure was selected for a theoretical investigation into the incorporation of metal dopants for nuclear intentional forensics applications. The two lattice types of this phase, tetragonal (I41/amd) and orthorhombic (Fddd), were investigated and found to be energetically identical, and as such the smaller tetragonal structure was selected for doping. Three transition metal dopants (Cr, Fe, and Ni) were incorporated into the structure interstitially and substitutionally at a total of six different sites. The most energetically favorable of these were investigated further through analysis of lattice parameters, bond distances, X-ray diffraction (XRD) patterns, and densities of states (DOS). These analyses led to the conclusions that interstitial doping of these three transition metals is much more energetically favorable than substitutional doping, and that Cr is the most likely candidate overall with a negative value for its defect formation energy.
Recieved from ProQuest
Nicholas James Wilson
Wilson, Nicholas James, "Density Functional Theory Study of Dopant Incorporation into Gamma-UO3" (2023). Open Access Theses & Dissertations. 3946.