b'results that have been generated in the AFC and compiles data published in peer-reviewed journalsATF handbooks, like the one prepared here, provide a associated with the propertiescritical source of non-proprietary data to evaluate fuel of Cr-doped UO 2 . Results, directperformance metrics and validate models being developed comparisons with undoped UO 2 , andacross the nuclear enterprise.recommendations were compiled in a non-proprietary handbook. Proper-ties determination and comparisons throughout the handbook wereconditions affected the final grain made based on Cr 2 O 3doped UO 2 sizes, especially when using CO 2samples (750 ppm to 7800 ppmmixtures. This work reports a additive) sintered at LANL. maximum average grain size of 528 mm obtained after initially Sintering tests combined withdoping UO 2with 4800 ppm Cr 2 O 3solubility limit and chromiumand using a wet Ar/H 2atmosphere.incorporation data in UO 2allowed for recommendations to be madeThermophysical properties determi-on the fabrication of Cr-dopednation of Cr-doped UO 2 , including UO 2 . Sintering above 1700C withspecific heat capacity, linear appropriate oxygen potential forthermal expansion, coefficient of the sintering to occur in the CrO (l) thermal expansion, and melting phase prevented early Cr/Cr 2 O 3 temperature showed no appreciable precipitation as shown in Figuredifferences compared to undoped 1. Inductively Coupled PlasmaUO 2 . Coefficient of thermal expan-Optical Emission Spectroscopysion as a function of temperature measurements showed consistent Crcan be seen in Figure 3. Thermal volatility of ~ 48 % during sintering,diffusivity (and thermal conduc-in agreement with recent literaturetivity) presented a small decrease reports. These results can be seencompared to undoped values above in Figure 2. The current proposed2500 ppm Cr 2 O 3in UO 2 , which solubility limit of Cr in UO 2is ~ 700was associated with the higher to 1200 ppm Cr in UO 2(~ 1000 todefect concentration in the mate-1750 ppm Cr 2 O 3equivalent). rial generated by the Cr additive.Lattice parameter contractedDiscussion on the lack of published with increasing Cr content up towork on the mechanical proper-the solubility limit, indicatingties as well as PIE on Cr-doped an assimilation in the UO 2latticeUO 2showcased the current gap as opposed to a secondary phasesurrounding this topic and revealed formation. No significant variationsfuture work opportunities.were observed above. Sintering 2023|AFC ACCOMPLISHMENTS 43'