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Uranium dioxide (UO 2) is the standard fuel used in light water reactors (LWRs). However, it has a low thermal conductivity that ultimately limits its performance both during normal operation and in accident conditions. Adding a material with high thermal conductivity is a potential approach to enhance the thermal conductivity of UO 2. Forming an interconnected structure of high-conductivity material can significantly enhance the overall thermal conductivity of the composite. Molybdenum (Mo) has been used as an additive material in UO 2 composites previously. A new method for the fabrication of interconnected UO 2− Mo composites using pre-sintered UO 2 granules to improve the continuity of Mo channels was investigated in this study. UO 2 –10 wt% Mo composites were produced using UO 2 granules and 1073 K and 1473 K pre-sintered UO 2 granules, followed by spark plasma sintering (SPS) of the mixtures at 1473 K for 5 min. The composites were characterised using scanning electron microscopy and X-ray diffractometry and their thermal conductivities were measured by the laser flash method and compared with a reference UO 2 pellet. At a maximum measurement temperature of 1073 K, a 52 % increase in thermal conductivity was observed in the composites containing UO 2 without pre-sintering, and UO 2 pre-sintered at 1073 K. The increase was 31 % for composites manufactured from UO 2 pre-sintered at 1473 K. These results suggest that higher temperature pre-sintering may be detrimental to forming interconnected Mo structures. [ABSTRACT FROM AUTHOR]