Assessing molten chloride salt components: Insights from a test loop experiment

Molten chloride salts have gained significant attention in recent years due to their growing utilization in various industrial applications, including Gen IV molten salt nuclear reactors, nuclear-spent fuel pyro-processing, and thermal energy storage. This study is concerned with addressing challenges associated with handling molten chloride salt in the construction of two test rigs and a series of experiments. It focuses on the reliability and effectiveness of high-temperature resistant mechanical valves, customized freeze valves, and Venturi flow meters in controlling and measuring the flow of molten salt at elevated temperatures. The results reveal that mechanical valves can effectively regulate the flow rate of molten salt, but their back seating seals were compromised after only a few operational cycles due to the corrosive nature and wetting properties of the molten salt. Conversely, the freeze valve was unable to control the flow rate, but experimental evidence confirmed that flow regulation was possible by incorporating an internal heating cable allowing or blocking passage. Experiments also demonstrated that a customized Venturi flow meter and balance can estimate the flow rates of molten chloride salt at high temperatures. However, these estimates have high standard deviations, particularly at higher flow rates, with maximums of 14.6 g/s for the balance and 9.71 g/s for the Venturi tube. Additionally, the study discusses various aspects relevant to restarting a molten salt test rig after it has cooled down to room temperature. This experimental study offers some crucial insights into the challenges associated with handling molten chloride salt and propose potential solutions that could expedite the development of molten salt technology in nuclear industry.