Development of High Temperature Transport Technologies for Molten Salt and Liquid Cadmium in Pyrometallurgical Reprocessing

Pyrometallurgical reprocessing technology is currently being focused in many countries for closing actinide fuel cycle because of its favorable economic potential and an intrinsic proliferation-resistant feature due to the inherent difficulty of extracting weapons-usable plutonium. The feasibility of pyrometallurgical reprocessing has been demonstrated through many laboratory scale experiments. Hence the development of the engineering technology necessary for pyrometallurgical reprocessing is a key issue for industrial realization. The development of high-temperature transport technologies for molten salt and liquid cadmium is crucial for pyrometallurgical processing; however, there have been very few transport studies on high-temperature fluids. In this study, a salt transport test rig and a metal transport test rig were installed in an argon glove box with the aim of developing technologies for transporting molten salt and liquid cadmium at approximately 773 K. It was demonstrated that; using a centrifugal pump, molten salt at 773 K could be transported at a controlled rate from 4 to 8 dm³/min against a 1 m head. The transport behavior of the molten salt was found to be similar to that of water, and could be predicted from their similarity of kinematic viscosity. On the other hand, the transportation of liquid cadmium at approximately 700 K could be controlled at a rate of 0.5 to 1.6 dm³/min against a 1.6 m head using the centrifugal pump.