b'Project Description: Accomplishments:This research is aiming to measureA challenge with elevated the mechanical properties of hightemperature testing of some uranium density fuel in support of thebased compounds is oxidation. In accident tolerant fuel campaign.order for the elevated temperature While there has been research intoNI of the accident tolerant high the thermophysical properties ofdensity fuels to be successful the these accident tolerant fuel forms,oxygen in the NI chamber needed there has been little research intoto be controlled or displaced. This the mechanical properties whichwas achieved by modifying the are needed for the modeling of thenanoindenter with additional gas pellet clad mechanical interaction. Infeedthroughs to displace the oxygen this work the development of SSMTin the chamber with a cover gas such for uranium-based compounds overas argon or argon+6% hydrogen temperature is being evaluated andin order to inhibit the oxidation developed. SSMT can enable the rapidof the samples. Utilization of an assessment of research size batches ofinert gas in the chamber limits different materials. The developmentthe max load of the transducer to of these SSMT techniques on fresh3-4 mN limiting the depth of the fuel would facilitate their use onindents to approximately 100 nm irradiated fuel in the future. Ain these harder ceramic materials. benefit of using these techniques onWhile this is a sufficient depth, to irradiated fuel would be the smallmeasure the mechanical properties volume of material needed whichit does limit the volume of material would greatly reduce the sourcesampled to the near surface region. temperature and safely allow testingDevelopment and evaluation of of the irradiated fuel outside of hotthe high temperature NI setup cells. In this work nanoindentationused a graded approach to assess (NI) was used to the measure thethe feasibility of the technique. elastic modulus and hardness of highFirst, CeO 2was measured up to density accident tolerant fuels at elevated temperature.2019|AFC ACCOMPLISHMENTS 65'