Fabrication method and thermal conductivity assessment of molybdenum-precipitated uranium dioxide pellets

UO2 pellets containing molybdenum networks were fabricated when UO2 pellets mixed with 3 or 5 wt% MoO3 powder were sintered in the CO2/CO ratio of 19/1 and then annealed in an H2 atmosphere. The thermal diffusivities of UO2 and Mo-precipitated UO2 pellets were measured in the range of 298–1673 K by a laser flash method and their thermal conductivities were calculated from the thermal diffusivity, the sample density and the published specific heat capacity data. The temperature dependency of the thermal conductivity up to 1673 K in UO2 and Mo-precipitated UO2 was found to be modeled well using the conductivity equation, κ = (A + BT)−1. The thermal conductivity of the Mo-precipitated UO2 was higher than that of the pure UO2.