In Situ Electrochemical Sensor for Oxygen Determination in High-Temperature Molten Salts

Statement of the Problem or Situation that is Being Addressed: Nuclear power is and will continue to be a key component of the energy technologies portfolio for the US. High-temperature molten salts are used as a liquid fuel medium and as a heat transfer fluid in several advanced reactor systems as well as heat storage and heat transfer fluids for concentrated solar power. Both the design and operation of these systems as well as thermophysical and thermochemical measurements for databases require oxygen determination of the chosen salt system as a function of composition and temperature. New, robust, and easy-to-use high-temperature sensors capable of measuring the oxygen content of high-temperature molten salts are required. Statement of how this Problem or Situation is Being Addressed: An existing high-temperature molten salts reference electrode platform technology that utilizes a thermodynamic reference electrode and also simultaneously measures the temperature and open circuit potential of the high-temperature molten salts will be refined and further developed to include a high-temperature molten salts oxygen sensor. This additional functionality is accomplished by incorporating an additional sense electrode(s) and developing and demonstrating electrochemical methods for the quantification of oxygen in high-temperature molten salts. Planned Phase I Effort: A balanced program of experiments, first principles, engineering models, process simulation, and analyses will be used to design, develop, fabricate, and evaluate a proof-of-concept high-temperature molten salts O2 sensor for this demanding application. Fundamental electroanalytical techniques will first be implemented for the determination of oxygen in high-temperature molten salts using a tradition three-electrode electrochemical cell and then this method will be incorporated in the high-temperature molten salts oxygen sensor. Simulations and cost models will be established to identify cost drivers and to evaluate trade-offs between design, performance, and cost. A detailed commercialization plan will be developed and commercialization partners will be identified for participation in Phase II. Commercial Applications and Other Benefits: The proposed approach will help to enable next-generation nuclear power generation which will have a significant positive effect on power generation and CO2 emissions in the US and worldwide. Reducing the reliance on fossil fuels and increasing the supply of energy produced from nuclear fuels will have an enormous impact on US energy security and US energy demand with abundant emission-free electricity. In addition, the high-temperature molten salts oxygen sensor developed for this application can be used to corrosion monitoring and control in other molten salt systems such as concentrated solar power.