AER/I Seminar

About the event

Speaker:  Christian Wentzell

Group:  Dr. Moreau Group

Title:  A Review of Hydrothermal Synthetic Techniques and Analysis Towards the Formation of UO2

Abstract:

With UO2 being the predominate nuclear fuel, various methods of its production have been investigated. Currently thermal decomposition is the primary method and while this is effective for the production of bulk-UO2, nano-UO2 requires a more controlled synthesis due to its thermodynamic instability. This discussion will cover an alternative synthetic method designed to produce nano-UO2 and the analytical techniques used to investigate the resulting particles. In this “hydrothermal” method, organic precursors are heated alongside water in a sealed autoclave, producing an autogenic pressure. This combination of pressure, heat, and water causes the precursor to decompose forming UO2 nanoparticles. Due to the lack of a surfactant which would normally protect the nanoparticle’s surface, they quickly aggregate to form larger particles on the micrometer scale. An interesting characteristic of these particles is that they contain nanoscale grains, while having an overall bulk morphology as shown by Electron Microscopy. X-ray diffraction is used to confirm the crystallographic phase of the resulting particles, and High Energy Resolution-X-ray Absorption Near Edge Structure (HR-XANES) is used to determine the oxidation state of the Uranium. Each of these techniques produces a variety of results that in culmination confirm the synthesis of UO2 particles.