有效热导率是芯块热导率和气隙热导率的综合描述。本文推导了有效热导率表达式,测量在不同的反应堆功率下的有效热导率值,获得了当芯块中心温度为632—1988℃时的有效热导率数据。结果表明,有效热导率开始阶段随中心温度升高而升高,然后下降;当芯块中心温度大于1800℃左右时,有效热导率继续随中心温度升高而升高。文中讨论了芯块的形状因子、包壳材料和包壳内壁温度对有效热导率的影响。 The effective thermal conductivity is a comprehensive description of the thermal conductivity of the pellets and the thermal conductivity of the air gap. In this paper, we derive the effective thermal conductivity expression and measure the effective thermal conductivity at different reactor power, and obtain the effective thermal conductivity data when the center temperature of the pellet is 632-1988 ℃. The results show that the effective thermal conductivity increases with the increase of the center temperature and then decreases. When the center temperature of the core is more than 1800 ℃, the effective thermal conductivity continues to increase with the rise of the center temperature. In this paper, the influence of the shape factor of the pellet, the cladding material and the temperature of the cladding inner wall on the effective thermal conductivity is discussed.