b'Figure 3. STEM/EDS map from theevaluate porosity and to facilitateAccomplishments:as-irradiated sample indicatingenergy dispersive x-ray spectroscopyRestructuring found in the fuel central Xe bubbles (red) along grain(EDS) mapping for fission productregion is suggested to be partially boundaries and intragranularly along the sample liftout at variousprecipitates and electron backscattercaused by the bubbles in the region. distances from the fuel/claddingdiffraction (EBSD) to study grainThis is supported by the strong interface. Yellow precipitates arestructure changes in the material.correlation between low angle grain Mo+Tc+Ru, Blue are Rh+Pd, andScanning transmission electronboundaries (LAGBs) and porosity White are five metal particlesmicroscopy (STEM) coupled withsize and shape. It is suggested that EDS was used to assess microstruc- temperature has a stronger effect than ture and Xe gas bubble evolution onburnup across an individual fuel pin, a nanometer scale at selected regionsmaking it probable that the clean-across the fuel pin. Microscopy wasgrained central region of the fuel is the conducted to better understand HBuresult of higher temperatures wiping structure and its effect on fragmen- out the LAGBs and LAGB-forming tation, and to better understand thestructures (dislocations) from this possible driving mechanisms of HBuregion. Future work intends to run structure restructuring. simulations to assess the impact of 28 2022|AFC ACCOMPLISHMENTS'