2018 | AFC ACCOMPLISHMENTS 55 Figure 1: Sievert's apparatus used for hydrogen absorption studies of U3Si2. oxygen levels below 0.1 ppm; once the desired temperature was reached, the steam/argon mixture was flowed through the system and sample mass change as a function of temperature and time was recorded. Results showed that below 350°C, steam oxidation does not represent a signifi- cant degradation mode, as mass gain under these conditions was negligible and pellet integrity was maintained (no spallation of material).This is consistent with previous work at LANL under similar conditions. Sieverts’ gas absorption measurements were simultaneously performed on sintered compacts of U3Si2 in pure hydrogen at the Sigma Division of LANL. Samples were loaded into a steel reaction chamber in an inert glovebox. The reaction chamber was sealed, connected to a gas manifold of known volume that comprised the Sieverts’ apparatus, and then evacuated.An annotated image of the experimental setup is shown in Figure 1.