【摘要】 核燃料包壳热导率是核燃料元件传热性能研究和核安全设计的重要参数，SiC复合包壳的双层结构和其内层的SiC/SiC复合材料特性增加了预测包壳导热性能的复杂性。为预测双层SiC复合包壳及内层复合材料热导率，基于Markworth有效介质理论，考虑孔隙率、温度、中子辐照等因素对SiC/SiC复合材料热导率的影响，在Markworth有效介质理论模型的基础上进行修正，计算了第二代、第三代SiC纤维增强的不同类型SiC/SiC复合材料热导率，并建立了双层SiC复合包壳热导率计算模型，初步预测了核电厂稳态运行期间双层SiC复合包壳的热导率。计算结果表明，核电厂稳态运行4个月后，辐照肿胀变形达到饱和，含第二代纤维的包壳热导率为3.9 W/(m·K),含第三代纤维的包壳热导率为4.8 W/(m·K)。更多还原

【Abstract】 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).更多还原