2017 | AFC ACCOMPLISHMENTS 63 This work highlights ongoing efforts to mitigate oxidation of high uranium density fuel powders, which should relax the air handling constraints of these fuels in a commercial environment. temperatures. However, an additional feature is observed. Needle-like precipitates can be found in the sample interior.These have been identified as a hydride phase. Recent work at LANL has established the ability of hydrogen alone to fully pulverize U3Si2 samples at these temperatures. It is believed that the strain induced by the formation of U-Si-H phases (precipitation of the only reported structure, U3Si2H1.8, would result in a volume increase of roughly 10%), leads to pulverization of the material once its concentration exceeds a critical threshold. Better understanding of this behavior is needed to assess the importance of this finding to LWR deployment of U3Si2.The impact of hydrogen as resulting from H2O oxidation following a cladding breach during normal operation is the direct motivation for the above work, but at higher temperatures and pressures hydrogen will remain important as a major chemical actor during a LOCA. Ongoing work will examine hydrogen solubility, kinetics, thermo- dynamics, and structural implications of hydriding in the U3Si2 system.