Effect of Particle-Shape And Distribution On Thermal And Electrical Conductivities in U3Si-Al Dispersion Fuels

Abstract

Two kinds of U3Si particles, longish-angular and spherical, have been prepared by comminution of a cast alloy and atomization of an induction melt, respectively. During the extrusion of U3Si-Al powder mixture the longish-angular U3Si particles tend to align along the extrusion direction and the spherical particles are randomly distributed. Along the extrusion direction, the thermal diffusivity and electrical conductivity of the comminution processed fuel are not much different from those of atomization processed fuel. Along the transverse direction, on the other hand, the thermal diffusivity and electrical conductivity of the atomization processed fuel are appreciably higher than those of comminution processed fuel. The conductivity difference between the two kinds of fuels has been explained by differences in microstructure, particle shape and distribution, and compared with a theoretical analysis based on a modified method of serial and parallel additions.