Hot Isostatic Pressing (HIP): A novel method to prepare Cr-doped UO 2 nuclear fuel

The addition of Cr 2 O 3 to modern UO 2 fuel modifies the microstructure so that, through the generation of larger grains during fission, a higher proportion of fission gases can be accommodated. This reduces the pellet-cladding mechanical interaction of the fuel rods, allowing the fuels to be “burned” for longer than traditional UO 2 fuel, thus maximising the energy obtained. We here describe the preparation of UO 2 and Cr-doped UO 2 using Hot Isostatic Pressing (HIP), as a potential method for fuel fabrication, and for development of analogue materials for spent nuclear fuel research. Characterization of the synthesised materials confirmed that high density UO 2 was successfully formed, and that Cr was present as particles at grain boundaries and also within the UO 2 matrix, possibly in a reduced form due to the processing conditions. In contrast to studies of Cr-doped UO 2 synthesised by other methods, no significant changes to the grain size were observed in the presence of Cr.