Fabrication technique of pellets has been investigated. Powder mixtures of were milled in two different ways-dry and wet milling. Milled powder was compacted and sintered to pellets. The wet-milled powder leads to a pellet having a high sintered density and uniform distribution of U and Th, compared to the dry-milled powder. The sintered density of a pellet tends to decrease by increasing the content of . The thermal conductivity of pellets was measured by the laser flash method. The thermal conductivity of the pellet is higher than that of the pellet, and the thermal conductivities of pellets containing pellets are lower than that of the pellet.