钨基二氧化铀芯块的热导率研究

通过无压烧结工艺以及放电等离子烧结工艺在1700℃下烧结得到了钨基二氧化铀芯块。无压烧结芯块密度为95.1-95.6%TD,放电等离子烧结芯块密度为96.2-97.9%TD(理论密度)。测定了不同UO2含量钨基二氧化铀芯块的热导率,含有30%UO2的钨基二氧化铀芯块室温热导率为63.3-65.4W/m·K,而含有60%UO2的钨基二氧化铀芯块室温热导率下降至36.1-37.7W/m·K。利用Maxwell、Bruggeman以及Every模型对钨基二氧化铀芯块的热导率进行了计算,计算结果与实际存在一定差异。引入晶粒尺寸以及孔隙率等影响因素对Maxwell模型进行了修正,修正模型热导率计算值与实际值符合较好。

Tungsten based uranium dioxide(UO2-W)pellets had been prepared under 1700℃by pressureless sintering process and spark plasma sintering process.The density of pellets obtained by pressureless sintering process were 95.1-95.6%TD(theoretical density),and the density of pellets obtained by spark plasma sintering process were 96.2-97.9%TD.The thermal conductivity of varied uranium dioxide content UO2-W pellets had been measured,the thermal conductivity of UO2-W pellet decreased from 63.3-65.4W/mK to 36.1-37.7W/mK while the content of uranium dioxide increased from 30%to 60%.Also the thermal conductivity of UO2-W pellets had been calculated by Maxwell、Bruggeman and Every model,the calculated value of thermal conductivity was dif ferent with the actual value.The Maxwell model was optimized by introducing crystal size,porosity as correction factor.The result calculated by the optimized Maxwell model was in good agreement with the actual value.