Design and Experimental Investigation of Fluoride Volatility Fluidized Bed Reactor

China’s nuclear energy development is implemented through a three-step strategy of pressurized water reactor-fast reactor-fusion reactor, accompanied by closed nuclear fuel cycle technology. The high burnup spent fuel from fast reactor generates intense radioactivity, creating technical barriers for conventional aqueous reprocessing. Dry reprocessing technology must be urgently developed to achieve closed fuel cycles. In order to develope a novel fluidized bed reactor prototype and process parameter system for high-temperature fluorination reactor design and process control system, the fluorination-volatilization dry reprocessing was focused, a carrier-material collaborative fluidization mode was proposed based on spent fuel fluorination-volatilization characteristics, alumina particles (280 μm) were selected as fluidization carriers to ensure material stability. Operational gas velocity was determined by combining theoretical critical fluidization velocity (0.041 3 m/s) with fluidization dynamics calculations, enabling structural optimization of the reactor. An integrated filtration-quenching device was designed with a bend-tube pre-distributor + 3 mm nickel ball-packed distribution plate configuration and automatic sealing system to ensure long-term reliability. Temperature field distribution and particle fluidization behavior were systematically analyzed through experiments and numerical simulations. Fluorination tests using UF₄ simulated materials were conducted to acquire critical process parameters. The experimental results demonstrate that the reactor core stably maintains 650 ℃ under continuous operation. Characteristic fluidization curves confirm dynamic bed stability in high-temperature environments. During fluorination tests at temperature of 550 ℃ with fluorine gas flow of 20 L/min and 100 g UF₄ feed, a 99.4% UF₆ conversion rate is achieved within 2 h. These data validate the feasibility of the fluidized fluorination technical route. In summary, a prototype fluidized bed reactor system suitable for dry reprocessing of fast reactor spent fuel is successfully established. The design parameters and operating conditions are demonstrated to effectively support high-efficiency fluorination reactions at elevated temperatures, providing technical foundations for engineering applications. Subsequent studies should prioritize authentic spent fuel verification and long-term operational stability tests to accelerate industrial implementation of fluorination-volatilization technology.