Synthesis and Characterization of UO 2 Feedstocks containing Controlled Dopants
Within the Advanced Fuels Campaign, the Oak Ridge National Laboratory is looking into the fabrication of high-performance UO 2 fuel candidates. The aim of this study was to develop a suitable fabrication avenue to synthesize UO 2 feedstock with controlled dopants to enhance UO 2 grain growth within these fuel candidates. Enlarged UO 2 grains in a nuclear fuel pellet are expected to slow down fission gas diffusion, which would be a preferred property for a high-performance fuel compared to fission gas diffusion in standard UO 2 . The unique fabrication processes for microspherical feedstocks via the internal gelation approach at the Oak Ridge National Laboratory have been developed further to enable the dopant uptake within the UO 2 microspheres. Mn and Cr were added via infiltration and/or addition of the dopant to the starting broth of an internal gelation experiment. The dopants were added in various amounts (ppm) into UO 2 . Even though large amounts of these dopants volatized during sintering, scanning electron microscopy images of the microstructure revealed large UO 2 grains of up to 80 μm for the pellets that were prepared from doped microspherical feedstocks.