Multi-electrode Array Sensor for Long-Duration Redox Potential Measurements

Development of molten salt reactors MSRs) is dependent on the ability to monitor and control salt chemistry to avoid corrosion of structural materials. Electrochemical instruments can effectively perform this by measuring the redox potential of the salt, but the instrument electrodes) must have known stable potentials over long durations. A useful instrument must: use electrodes made from materials which are chemically compatible with the salts; not be affected by high temperatures or thermal cycling; survive in flowing salt; operate in situ, without the need the break to system seal; and operate for months or years without manual maintenance. Recent tests at Argonne National Laboratory have shown that a dynamic reference electrode approach can provide high-quality measurements over far greater spans of time. The approach achieves long-term stability by electrolytically regenerating a metal layer on the electrodes on demand, effectively repairing electrodes in situ. Sporian Microsystems will leverage prior experience with high-temperature materials and seals, and integrated sensor electronics to develop ANL’s prototype design into a commercial product. 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 and electronics designs based on ANL’s original; and 3) proof-of-principle testing & demonstration using prototype hardware and electronics in an ANL test system. The proposed technology will help to enable MSR technology by providing a means of studying molten salt chemistry in real time. In the long term, the technology will improve condition monitoring and controls in MSR plants by characterizing salt chemistry and corrosion potential in real time, enabling plants to run more efficiently and reliably. 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 developed sensor will have additional applications for nuclear power generation, fossil- and solar-fueled power generation systems, metal and glass manufacturing, and other harsh- environment industrial processes.