Thermal Conductivity of Simulated Fuels with Dissolved Fission Products

The thermal diffusivity of simulated fuels with dissolved fission products was measured by using the laser-flash method in the temperature range from room temperature to 1,473 K. Three kinds of simulated fuels with an equivalent burn-up of 3, 6, and 12 at%were used in the measurement. The thermal diffusivity and the thermal conductivity of the simulated fuels with the dissolved fission products decreased, as the temperature and the equivalent burn-up increased. The thermal conductivities of simulated fuels with equivalent burn-ups of 3, 6, and 12 at% were lower than that of UO2 by 84.70, 67.17, and 44.97% at 300K and 99.17, 89.88, and 80.56% of UO2 at 1,473 K, respectively. The difference in the thermal conductivity between the simulated fuel and UO2 was large at room temperature, and it decreased as the temperature increased. The thermal resistivity of the simulated fuels increased linearly with temperature up to 1,473 K.