2017 | AFC ACCOMPLISHMENTS 79 Use of a separate effects approach shows potential to isolate effect of industrial fabrication on properties of unirradiated U3Si2. altered, as is the case in this study. Figure 1 plots results for samples synthesized in this study alongside data for high purity U3Si2 and also the thermal diffusivity that would be expected for U3Si2 containing 2 and 10 volume percent UO2 based upon a rule of mixtures calculation. Results highlight that while oxygen contents up to 10 volume percent (approximately equal to 10,000 wppm oxygen in U3Si2 feedstock) are found to have an overall minimal effect on thermal conductivity, the degradation appears to be slightly more than would be expected due to UO2 alone. It is hypothesized that this effect may be caused by microstructural evolutions more complex than captured by a simple model of a UO2-U3Si2 composition. Further analysis of the microstruc- tures of these samples is ongoing to better understand this behavior and its implications on use of U3Si2 as a commercial Light Water Reactor (LWR) fuel.