Development of High-Temperature Transport System for LiCl-KCl Molten Salt in Pyroprocessing

Pyroprocessing technology is one of the most promising technologies for many advanced fuel cycle scenarios with favorable economic potential and intrinsic proliferation resistance. In pyroprocessing technology, the development of high-temperature transport technologies for molten salt is a crucial prerequisite and a key issue in the industrialization of pyroreprocessing. However, there have been a few transport studies on high-temperature molten salt. Three different salt transport technologies (gravity, suction pump, and centrifugal pump) were investigated to select the most suitable method for LiCl-KCl molten salt transport. The suction pump transport method was selected for molten salt transport owing to its flexibility. An apparatus for suction transport experiments was designed and installed for the development of high-temperature molten salt transport technology. Several preliminary suction transport experiments were carried out using the prepared LiCl-KCl eutectic salt at 773 K to observe the transport behavior of LiCl-KCl molten salt. For the experiments, ∼2 kg of LiCl-KCl eutectic salt was prepared by mixing 99.0% purity LiCl and KCl and drying in a convection dry oven at 473 K for 1 h. The experimental results of a laboratory-scale molten salt transport using a suction method showed a 99.5% transport rate (ratio of transported salt to total salt) under a vacuum range of 0.0133 to 1.33 kPa at 773 K. From experimental results on the mass flow rate according to suction transport time, the mass flow rate according to suction time is 1.54 kg/min. In addition, to establish engineering-scale salt transport technology, the PRIDE salt transport system was designed and installed in an Ar cell, on the second floor of the PRIDE facility, for engineering-scale salt transport demonstration, and its performance was confirmed.