The thermal conductivity of nuclear fuel cladding is an important parameter for the study of heat transfer performance of nuclear fuel elements and nuclear safety design.The double-layer structure of SiC composite cladding and the properties of SiC/SiC composite material on its inner layer increase the complexity of predicting the thermal conductivity of the cladding.To predict the thermal conductivity of the SiC double-layer composite cladding and inner-layer composites,based on the Markworth effective-medium theory,the effects of porosity,temperature,neutron irradiation and other factors on the thermal conductivity of SiC/SiC composites were considered,the thermal conductivity of different types of SiC/SiC composites made of second and third generation SiC fibers was calculated on the basis of the modified Markworth effective medium model.The thermal conductivity calculation model of the SiC double-layer composite cladding was established,and the thermal conductivity of the SiC double-layer composite cladding during the steady-state operation of nuclear power plants was initially predicted.The calculation results show that after 4 months of steady-state operation of the nuclear power plant,the irradiated swelling deformation reaches saturation,the thermal conductivity of the cladding containing the second generation fiber is 3.9 W/(m·K),and that of the third generation fiber is 4.8 W/(m·K).
关键词
压水堆/燃料包壳/热导率/SiC复合材料/有效介质模型
Key words
Pressurised water reactors/Fuel cladding/Thermal conductivity/SiC/SiC composites/Effective medium model
维普
万方数据