2017 | AFC ACCOMPLISHMENTS 66 scanningTEM (STEM) was performed in the Low Activation Materials Development & Analysis (LAMDA) Laboratory using the FEI F200X Talos instrument. Characterization performed using theTalos consisted of high resolution STEM and energy dispersive X-ray spectroscopy (EDS). Multivariate statistical analysis was used to analyze the large EDS datasets and assess the chemical composition. Results of the EDS scans are high- lighted in Figure 1.The elemental maps show two main surface features. First, a region of O enrich- ment and absence of Si can be seen at the sample surface. A subsurface region of U depletion and Si enrich- ment is found next before transition to bulk U3Si2 of relatively constant U and Si content.This chemical behavior, although on a vastly smaller length scale, confirms that Figure 2. Representative EDS line scan obtained from a U3Si2 sample highlighting the native oxide structure. Results highlight the ~10 nm thick oxide (likely UO2 ) and U-Si region of slight Si enrichment relative to the U3Si2 bulk in the subsurface region.