b'temperatures, the possibility of subsequently examined using X-ray U 3 Si 2hydriding was considered diffraction (XRD) to characterize the and examined. As a result, this workevolution of the hydride phase as a is imperative in understanding function of hydrogen-to-uranium U 3 Si 2degradation under potential(H/U) ratio and temperature. LWR conditions. Sieverts gas absorption Previous work in FY17 evaluatedmeasurements were performed U 3 Si 2hydriding performance inon button fragments of U 3 Si 2with hydrogenated water (5 ppm H2known masses at the Sigma Division at 300 C) and in 6% H2/Ar gasof Los Alamos National Laboratory showed pulverization that was(LANL). Measurements were correlated with the presence ofperformed at temperatures from a secondary phase hypothesized250 to 500 C in 50 C intervals. to be hydride lamellae. In FY18,Hydrogen absorption was performed hydrogen absorption experimentsby titration of known volumes of of U 3 Si 2began by examining thehydrogen into the gas manifold and hydriding performance of sinteredmonitoring of hydrogen pressure pellets and button fragmentschanges to calculate the moles at 350 C. This work showedof hydrogen absorbed during a stark difference in hydrogenthe respective aliquot. Hydrogen absorption behavior due to surfaceabsorption experiments were conditioning effects. In FY19,terminated when samples no longer hydrogen absorption experimentsappreciably absorbed hydrogen, as were continued. Studies weremeasured by hydrogen pressure focused on hydrogen absorption andchanges in the gas manifold. desorption measurements at various temperatures ranging between 250 and 500 C. Hydrided samples were 2019|AFC ACCOMPLISHMENTS 51'