Prelim Defense – William Vance

About the event

Speaker: William Vance

Group: Dr. Xiaofeng Guo

Title: Thermochemical and Structural Analysis of the Thermal Oxidation Pathway for Advanced Nuclear Fuel Variants Under Off-Normal or Accident Conditions

Abstract: As technology continues to evolve and human civilization moves forward, the demand for energy is the highest it has ever been. Carbon emissions are a substantial challenge for the environment, so meeting this demand with coal and fossil fuels would have catastrophic consequences on the environment and the long-term health of the planet. One power source that is able to meet this demand without more carbon input into the atmosphere is nuclear energy. The primary fuel source in power generating nuclear reactors is enriched UO2, however this material has relatively low thermal conductivity, lower melting point, high thermal expansion, and low U density in comparison to other U-based accident tolerant fuel (ATF) candidates. These candidates include, UN, UC2, UCO, U3Si2, and more, all of which offer higher U loading and superior performance. Despite these advantages, there are gaps in the literature surrounding the thermodynamic and structural information regarding their thermal oxidation, which is of relevance under off-normal or accident conditions in which the fuel may be exposed to oxygen at high temperatures. The goal of this study is to fill these knowledge gaps by performing high-temperature in situ structural characterization using techniques such as X-ray absorption fine structure (XAFS), X-ray diffraction (XRD), and Raman spectroscopy to see real time structural changes in conjunction with calorimetry-based techniques such as differential scanning calorimetry (DSC) with thermogravimetric analysis (TGA) to elucidate the identity and characteristics of these intermediate phases.