Characterization and thermo-physical property evaluation of Th-6U-6Nb ternary alloy

Use of thorium-uranium fuel in the third stage is envisaged in the closed fuel cycle of India. Thorium offers number of advantages over uranium in-terms of physical, nuclear and thermo-physical attributes. In this regard, studies on thorium-niobium based binary alloy, as a sub-system of Th-U-Nb ternary fuel, was already initiated. In an endeavour to develop thorium and uranium based metallic fuel, which has high potential for breeder reactor and thermal reactor when alloyed with fissile material, Th-6U-6Nb alloy was investigated. The alloy was prepared by vacuum arc melting, using high purity Th, U and Nb metals. The alloy was then homogenization at 900 °C for 100 hrs. Characterization was carried out in terms of phases present by X-ray diffraction, microstructure by scanning electron microscope (SEM) and chemical composition and homogeneity by energy dispersive spectroscopy (EDS). Micro-hardness was determined by Vickers hardness tester. Thermophysical properties like coefficient of thermal expansion and transition temperature were determined using dilatometer and Differential Thermal Analyser (DTA) respectively