Danish molten salt reactor developer Saltfoss, formerly Seaborg Technologies, has hired South Korea’s national nuclear lab to help with the hard, unglamorous parts of its design. The company signed a two-year research contract with the Korea Atomic Energy Research Institute (KAERI), and World Nuclear News reported the deal on September 4, 2026. Saltfoss says its reactor is designed to run 24 years without refueling. No unit has been built.
The contract is worth about 3 billion Korean won, or $2.3 million. KAERI will provide research and development services using its existing facilities. It is not transferring ownership of its molten salt reactor technology or intellectual property. The work has four parts: pretreating fluoride molten salt to fuel-grade quality, fabricating and characterizing nuclear fuel, building and operating a natural-circulation molten salt test loop (a loop that moves salt by heat-driven flow instead of pumps), and evaluating how candidate structural metals corrode in molten salt at high temperature.
Saltfoss CEO Klaus Nyengaard said “Korea continues to be a cornerstone of our strategy.”
Im In-cheol, KAERI’s acting director, called the contract “a significant achievement” in which Korea’s original molten salt reactor technology was valued by a foreign private company.
The reactor behind the contract
The seaMSR-100 is reported at 100 MWe, or 250 MWt, per reactor, running at about 650°C and near-atmospheric pressure. Several reactors on a floating platform would give 100 to 600 MWe. The 24 years without refueling is the company’s design claim. Saltfoss has a long-standing partnership with Samsung Heavy Industries on the platform.
A 2025 World Nuclear News report said the fuel salt is not yet commercially available, so early barges would use low-enriched uranium fuel in a different form. It also said the first reactor is targeted for the first half of the 2030s, later than an earlier 2028 goal. For another floating reactor idea, see our story on the Newcleo barge.
Why It Matters to You
This is research work, so nobody can use or buy anything from it. If the reactor is ever built, the people who would feel it first are the customers of floating power platforms, and the company’s own target for the first reactor is the first half of the 2030s. Today the benefit is limited to steps toward proving fuel preparation and corrosion resistance.
What to keep in mind
- The 24-year interval is a design claim. The contract tests fuel preparation and corrosion, which are steps toward proving it.
- The $2.3 million contract is small next to the cost of building a reactor. It buys research services, not a reactor.
- Corrosion of structural metals in fluoride salt is a known challenge, and the KAERI trials have not reported results.
- The 2025 report described a 24-year operational life for the barge design. The 2026 report describes 24 years without refueling. Public sources don’t show how the two differ.
- No regulator has approved the design.
Quick answers
Is Saltfoss buying Korean reactor technology?
No. KAERI is providing research services with its existing infrastructure and is not transferring ownership of its technology.
Will the reactor really run 24 years without refueling?
That is the company’s design target. No seaMSR-100 has operated, so the claim is untested.
Sources
- World Nuclear News: Saltfoss enlists Korean services for MSR development (Sep 4, 2026)
- World Nuclear News: Denmark’s Seaborg changes name and adds to board (Apr 3, 2025)