Interfacial microstructure and thermal resistance of UO2/Mo composites fabricated by spark plasma sintering

Abstract The development of UO2/Mo composite pellets with enhanced thermal conductivity (TC) has been considered to be a promising route for improving the safety of nuclear reactors. The interfacial microstructure and especially the interfacial thermal resistance (ITR) of UO2/Mo composites could dominate the effective thermal conductivity (ETC) of the composites. In this work, the interfacial microstructure of UO2/Mo composites fabricated by spark plasma sintering (SPS) was investigated by high-resolution transmission electron microscopy (HRTEM) with energy dispersive spectroscopy (EDS) and auger electron spectroscopy (AES). The results indicated that UO2/Mo interface was a semi-coherent interfacial microstructure with an orientation of ( 220 ) UO 2 / ( 110 ) Mo and a lattice misfit degree of 0.117. Furthermore, there were no distinct interfacial products at the UO2/Mo interface. Based on the structure characterized above, the calculated ITR of the UO2/Mo composite was on the order of approximately 10-9 m2K/W.