A KGd(WO4)2 powder/Er2Ce2O7–SiO2 aerogel with low thermal conductivity and excellent radiation shielding performance for thermal insulation of nuclear power plants

To meet the application requirements of thermal insulation materials for nuclear power plants, Rare earth composite aerogel (KGd(WO4)2 powder/Er2Ce2O7–SiO2) were prepared by compounding rare earth precursor sol and rare earth powder with silica aerogel based on directional freeze drying method. The effect of thermal diffusivity of rare earth salt crystals on the thermal conductivity of rare earth composite aerogel was found, and the mechanism of the effect of the type and morphology of rare earth powder on the γ-ray shielding performance was explored. The irradiation and temperature resistance measurement shows that the KGd(WO4)2 powder/Er2Ce2O7–SiO2 aerogel can withstand 1 × 107 Gy γ-ray and high temperature baking above 1100 °C. KGd(WO4)2 powder/Er2Ce2O7–SiO2 aerogel is an ideal new generation multi-functional shielding and thermal insulation material for nuclear power plants because of its low thermal conductivity, excellent γ-ray and neutron radiation shielding, high temperature resistance and radiation aging resistance.