High-Temperature Flow Sensor for Molten Salt Reactors

MSR developers have identified a need for instruments that can monitor conditions of molten salt in test beds during the research and development stage, as well as for long-term application in both the primary (fuel) and secondary (coolant/heat transfer fluid) loops. Specifically, it has been noted that representative materials experiments require flowing salt, so instruments to measure salt flow rates are required to accurately monitor fluid conditions. Existing technology available to research labs and MSR developers were not designed for use in high- temperature molten salts, and they require significant post-market modifications for material compatibility. Even with such modifications, these instruments are not able to operate in the high operating temperatures anticipated in MSRs. Sporian Microsystems has previously developed a suite of high- temperature in situ sensors for pressurized water reactors and for the concentrating solar power (CSP) industries, including flow sensors for use in the carbonate and nitrate salts used in the CSP industry. Critical differences between solar and nuclear power applications preclude the direct application of one monitoring system to both applications; that is, differences in the salt chemistries and operating temperatures, and the presence of nuclear fuel will have significant effects on the sensor and packaging hardware designs. Thus, the primary objective of the proposed effort is to leverage Sporian’s prior work on harsh environment sensors and packaging to realize a multimodal flow+temperature sensor operable in molten fluoride and chloride salts at temperatures up to 750°C, and to experimentally evaluate/demonstrate the utility and viability (performance and cost) for MSR applications. The phase I effort will include: 1) working with universities, DOE national labs, and industry stakeholders to define system requirements; 2) evaluating and defining revised hardware/electronics architectures and designs; and 3) proof of principle testing/demonstration using benchtop-scale prototype hardware. The proposed technology will improve MSR test beds by providing an improved means of precisely monitoring fluid dynamics of molten salts, which is critical to studying chemistry and heat transfer properties. In the long term, the technology will improve condition monitoring and controls in MSR plants by providing information on fuel and coolant fluid conditions in real time, enabling plants to run more efficiently and reliably by allowing the reactor to run closer to its operational limits. MSR technology has benefits over other power generation technologies including efficient use of fuel, passive safety, improved load-following capability over other reactors, low emissions, and no need for a large pressure vessel. The technology has cross-cutting applications across the range of MSR designs, other nuclear power generation systems, fossil- and solar-fueled power generation systems, metal production systems, and other industrial processes.