The US Department of Energy (DOE) Oak Ridge National Laboratory (ORNL) has signed a $27m strategic partnership with Kairos Power to accelerate the technology needed to deploy a new generation of advanced nuclear reactors. ORNL will provide expertise and access to specialised facilities to review and evaluate various aspects of Kairos Power’s novel fluoride salt-cooled high-temperature reactor design, which uses TriStructural ISOtropic (TRISO).
ORNL will also manufacture components for reactor development and testing, and assess the performance of coated particle fuel following irradiation under conditions relevant to their planned reactor operation. The project’s outcomes will support the design, construction and eventual operation of Kairos Power’s planned Hermes demonstration reactors under construction in Oak Ridge, Tennessee, and subsequent commercialisation of its planned fluoride salt-cooled high-temperature reactor.
Kairos Power is building its Hermes demonstration reactor series at the Heritage Center Industrial Park (formerly the East Tennessee Technology Park) in the western portion of the Oak Ridge Reservation, some 16-19 kilometres from ORNL.
The site sits on 185 acres that previously housed the K-33 gaseous diffusion plant, a major enrichment facility during the Cold War. The campus will co-locate several facilities, including the Hermes 1 low-power test reactor (currently under construction), the Hermes 2 commercial-scale demonstration plant, and a non-nuclear engineering test unit (ETU 3.0).
In January Kairos Power finalised a contract with DOE to receive High-Assay Low-Enriched Uranium (HALEU), sourced from DOE material. This will be used for the start-up and operation of Hermes 1. Kairos Power was one of five companies conditionally selected by DOE to receive HALEU in April 2025 under the agency’s HALEU Availability Program and has now completed negotiations to secure the HALEU required for the Hermes 1 programme. The company will use the material to produce TRISO fuel pebbles for Hermes 1 in partnership with Los Alamos National Laboratory, using manufacturing processes developed and optimised in Kairos Power labs.
“Providing the scientific basis for new technology is what we do at Oak Ridge National Laboratory,” said ORNL Director Stephen Streiffer. “With energy demand expected to increase substantially by 2050, our continued partnerships with U.S. industry, including Kairos Power, are how we will bring more reliable, affordable energy to market.”
ORNL demonstrated the proof-of-concept and performance of the world’s first molten salt reactor 60 years ago and has helped nurture the continued development of molten salt reactor technology. DOE is investing up to $303m of risk reduction funding in Kairos Power’s Hermes demonstration reactors under the Advanced Reactor Demonstration Program (ARDP).
“DOE’s support has been instrumental in helping Kairos Power accelerate our path to technological maturity,” said Ed Blandford, chief technology officer and co-founder of Kairos Power. “By collaborating with Oak Ridge National Laboratory, we gain access to decades of expertise and a unique set of capabilities that we couldn’t find anywhere else. We are pleased to partner with the lab as we work to deploy safe, reliable advanced reactor technology that builds on Oak Ridge’s nuclear legacy.”
Over the next five years, ORNL will provide key learnings from testing and assessments conducted at its specialised facilities, including the Manufacturing Demonstration Facility, Coated Particle Fuel Development Laboratory, and Irradiated Fuels Examination Laboratory.
The scope of work includes:
- Assessing fuel manufacturing and synthesis methods to evaluate product quality and production methods for TRISO fuel particles;
- Understanding the properties of TRISO fuel pebbles to support a fabrication capability and quality control infrastructure;
- Completing a comprehensive spent fuel pebble management plan to include on-site cask storage, transportation and final disposition;
- Producing components using advanced manufacturing techniques to better understand how materials that come into contact with the salt, such as ceramics, carbon composites, and metallic materials, perform in extremely high temperatures;
- Enabling remote maintenance systems capable of operating under high temperatures with simultaneous exposure to radiation and corrosive salts.
“It’s exciting to see how our historical lineage in molten salt reactor technology and coated particle fuel are being leveraged with the lab’s more recent advances in additive manufacturing to support Kairos Power in building the first advanced reactor of its kind in our own backyard,” said Chris Petrie, interim section head of Nuclear Fuel Development at ORNL. “Our expertise, paired with Kairos Power’s iterative approach to progressively demonstrating the technology, allows us to learn faster and ultimately accelerate the deployment of more nuclear energy to the grid.”
The project marks the fourth partnership between ORNL and Kairos Power since 2020. These include 3D-Printed Nuclear Construction Forms (2025), a partnership with ORNL’s Manufacturing Demonstration Facility to develop large-scale 3D-printed polymer composite forms. These were used to cast complex, high-precision concrete structures for the Hermes reactor.
Additive Manufacturing for Prefabricated Elements (Dec 2023–2025) was a collaborative effort involving the University of Maine and ORNL to 3D-print specialised sinusoidal concrete form liners. This hybrid casting system for prefabricated structural elements aims to significantly reduce construction costs and timelines. The Initial Strategic Research & Development in 2020 was the foundational partnership that leveraged ORNL’s historic legacy in molten salt technology to refine Kairos Power Fluoride Salt-Cooled High-Temperature Reactor (KP-FHR) design.
“Partnerships like these are providing the economic wherewithal to build an energy ecosystem right here in East Tennessee,” said Andrew Nelson, ORNL’s interim director of the Nuclear Energy Fuel Cycle Division…. ORNL has a long history of driving innovation and efficiencies in the nuclear industry. Through impactful industry collaborations such as our ongoing partnership with Kairos Power, I am confident that we will see an ever-expanding portfolio of nuclear power plants in the future.”
