b'Figure 3. Subcapsule componentscontaining 6 of the 12 specimens areAccomplishments:prior to assembly expected to reach burnups betweenThe initial RB MiniFuel experiment 4550 MWd/kg-U and will remainusing Cr-doped UO 2fuel specimens in HFIR for 5 irradiation cycleswas inserted into HFIR in FY 2023. or approximately 125 irradiationThis effort included design of days. The second target containingthe subcapsule outer diameters the other half of specimens willand target fill gas compositions, remain in HFIR for 9 irradiationperforming extensive safety calcula-cycles, or roughly 225 irradiationtions to gain approval for HFIR days, allowing the fuel specimensinsertion, experiment procurement to reach burnups between 8696and assembly, and installation. MWd/kg-U. The two burnup rangesDesign calculations were performed were selected to provide someby first determining time-dependent insight to the relationship betweenheat generation rates (HGRs) in FGR and burnup at approxi- experimental components using mately constant temperatures. neutronics tools and then importing 46 2023|AFC ACCOMPLISHMENTS'