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Kairos Power's Engineering Test Unit 1 is the largest FLiBe molten salt system ever built and will be used to inform the design, construction, and operation of Hermes—a low-power reactor that the company is using to advance the development of its KP-FHR.
U.S. Department of Energy

Kairos Power successfully completed 1,000 hours of pumped salt operations after loading 12 metric tons of a molten fluoride salt known as “FLiBe” into its Engineering Test Unit (ETU) at its testing and manufacturing facility in Albuquerque, New Mexico.

The ETU is the largest FLiBe molten salt system ever built and will be used to inform the design, construction, and operation of Hermes—a low-power reactor that the company is using to advance the development of its KP-FHR.

The Hermes project is part of the U.S. Department of Energy’s Advanced Reactor Demonstration Program and could be operational in Oak Ridge, Tennessee, as early as 2026.

Engineering Test Unit

The ETU is a non-nuclear prototype at the same scale as Hermes. It’s being used to demonstrate key systems, structures, and components, test the supply chain, and gain operational experience that will be integrated into future iterations on the company’s path to commercializing KP-FHR technology. 

The team recently loaded FLiBe (a mixture of lithium and beryllium fluoride salts) into the unit to begin operation of the ETU. 

Kairos Power manufactured 14 tons of FLiBe for ETU at its Molten Salt Purification Plant in Elmore, Ohio.

The ETU program will be used to reduce technical, licensing, manufacturing, and construction risks for future Kairos Power reactors.

“Gaining experience with Flibe production and operations is fundamental to taking risk off the table towards KP-FHR commercialization,” said Mike Laufer, Kairos Power co-founder and CEO.“Iterative development with real hardware systems like ETU 1.0 is a pillar of our strategy to deliver a clean, safe, affordable technology with true cost certainty and, when combined with in-house manufacturing, provides a unique opportunity to move quickly so we can make an impact in the fight against climate change.”

What’s Next?

Kairos Power plans to operate the ETU for about five months before decommissioning the unit and constructing a second iteration, ETU 2.0.

The company plans to build a third iteration in Oak Ridge in 2024 to lay the groundwork for Hermes operations starting in 2026. 

Kairos Power is working to commercialize a 140 megawatt-electric high-temperature molten salt reactor that leverages robust TRISO fuel to deliver clean, firm energy that complements renewable power sources at a cost competitive with natural gas. 

The KP-FHR commercial reactor could be operational in the early 2030s. 

Learn more about our Advanced Reactor Demonstration Program