TRISO燃料颗粒等效导热系数理论模型研究

Theoretical Research on Effective Thermal Conductivity of TRISO Particle

三层各向同性碳包覆(TRISO)燃料颗粒由核芯和4层包覆层组成,具有良好的裂变产物包容能力,其等效导热系数是计算弥散微封装燃料等效导热系数的重要基础。本文首先从球坐标下基本导热方程出发,基于多相固体宏观等效导热理论,建立了TRISO燃料颗粒等效导热系数理论计算模型;然后,结合固-固二元复合材料等效导热系数Chiew-Glandt模型分析了锆基微封装燃料(M3)芯体等效导热系数。结果表明,本文开发的模型可有效模拟TRISO燃料等效导热系数。基于开发的TRISO等效导热系数模型计算获得了全陶瓷微封装燃料(FCM)的等效导热系数。

TRISO(tri-structural isotropic)fuel particle consists of a fuel kernel in the center coated with four layers,with good fission product retention capability.The effective thermal conductivity of TRISO fuel particle is an important basis for calculating the effective thermal conductivity of dispersed fuels.In the present work,the theoretical model of the effective thermal conductivity of TRISO particle is built based on the theory of the effective thermal conductivity in multiphase solids in the framework of spherical coordinate and then the effective thermal conductivity of metal matrix microencapsulated fuel(M3)is analyzed combined with the Chiew-Glandt model which is the effective thermal conductivity model for solid-solid binary composite.The results show that the present model provides an excellent prediction of the thermal conductivity of TRISO particle.Finally the effective thermal conductivity of fully encapsulated fuel(FCM)is presented.