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Project Name: Full Loop Thermodynamic Corrosion Inhibition and Sensing in Molten Chloride Systems
Funding Opportunity: Generation 3 Concentrating Solar Power Systems Lab Call
SETO Subprogram: Concentrating Solar-Thermal Power
Location: Aiken, SC
SETO Award Amount: $1,000,000
Awardee Cost Share: N/A

This project explores ways to prevent corrosion from molten chloride salts in Generation 3 concentrating solar power (Gen3 CSP) plants. Gen3 CSP systems will operate at temperatures as high as 750° Celsius, making them more efficient, but this requires a fluid, such as molten salt, that can move high-temperature heat without breaking down. Molten salts are cost-effective; however, if not properly controlled and maintained, they will corrode the metal pipes and other components in the system. Preventing corrosion is essential to extend the lifetime of the components in a CSP plant and keep costs down.

Savannah River National Laboratory Gen3 CSP Images
Left: A scanning electron microscope image of a nickel alloy used for CSP after exposure to corrosive salts. Right: Green areas contain nickel, and blue ones contain zirconium. Photos courtesy of Savannah River National Laboratory.


Savannah River National Laboratory has demonstrated that adding electrochemically active metals, like magnesium, to a molten salt mixture can control corrosion, though questions remain about how to best deploy this strategy in an operating plant. To develop corrosion-mitigation strategies for CSP plants, the team will explore various options, including lowering the melting point of magnesium by mixing it with other metals; coating the metal components with zirconium or titanium; and adding zirconium chloride or titanium chloride to the molten salt. The project team will also develop new methods for detecting corrosion as it occurs.


The proposed corrosion-prevention methods use elements that can both maintain a low electrochemical potential in the metal, meaning they make the metal less susceptible to corrosion, and facilitate the formation of a protective layer—stable carbide films—on it. This project will help reduce corrosion, making plants easier to maintain and more economical.