부산대학교 도서관

This paper describes a finite element model of the microstructure of dispersion type nuclear fuels, which can be used todetermine the effective thermal conductivity of the fuels during irradiation. The model simulates a representative region of thefuel as a prism shaped unit cell made of brick elements. The elements within the unit cell are assigned material properties ofeither the fuel or the matrix depending on position, in such a way as to represent randomly distributed fuel particles with a sizedistribution similar to that of the as manufactured fuel. By applying an appropriate heat flux across the unit cell it is possible todetermine the effective thermal conductivity of the unit cell as a function of the volume fraction of the fuel particles. Thepresence of a fuel/matrix interaction layer is simulated by the addition of a third set of material properties that are assigned tothe finite elements that surround each fuel particle. In this way the effective thermal conductivity of the material may also bedetermined as a function of the volume fraction of the interaction layer. Work is on going to add fission gas bubbles in the fuelas a fourth phase to the model.