Saltfoss told the NRC it wants to license a floating nuclear plant whose barges carry up to 600 MW

Saltfoss, the Danish molten salt reactor developer formerly known as Seaborg, has notified the U.S. Nuclear Regulatory Commission that it intends to begin pre-application engagement for a floating nuclear power plant. Its seaMSR-100 design is built from 100 MWe modules, and a single barge can carry up to 600 MW of electrical output. The company expects to file a Regulatory Engagement Plan with the agency in the first quarter of 2027.

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No reactor has been licensed, built or loaded with fuel under this plan. What happened this week is a letter of intent to a regulator, which starts a conversation that normally runs for years before any formal application lands.

Pre-application notice and the Part 53 route

World Nuclear News, which reported the notification on November 3, says Saltfoss wants to be the first advanced reactor developer licensed under Part 53, the framework the NRC issued in March. The commission describes Part 53 as an optional, risk-informed, performance-based and technology-inclusive route to licensing commercial plants, published as a final rule in the Federal Register on March 30, 2026. Saltfoss also says it would be the first advanced maritime small modular reactor licensed anywhere.

The Regulatory Engagement Plan is the next paper milestone. Filing it in early 2027 would tell NRC staff which topics the company wants to settle first, such as the safety case for a reactor that sits on a hull rather than on land. The announcement does not give a date for a construction permit or operating license application, and the company has not said how many barges it hopes to place in American waters or at American ports.

seaMSR-100 modules and 600 MW barges

The seaMSR-100 is a loop-style molten salt reactor that runs near atmospheric pressure at roughly 600 to 700 degrees Celsius on low-enriched uranium. Saltfoss says the fuel salt solidifies below about 500 degrees, which traps radioactive material, and that the reactor shuts down and drains by gravity without operator action or external power. Its own website describes each reactor as 100 MWe and designed for a 24-year operating life without refueling, with platforms combining several reactors for configurations from 100 to 600 MWe.

Potential customers named in the announcement are coastal industrial users needing power and heat, grid baseload operators and hyperscale data centers. A KAERI contract summary published in September adds the thermal figure, 250 MWt per reactor at about 650 degrees, which matters for industrial heat buyers who care about temperature as much as electricity.

Klaus Nyengaard, the company’s chief executive, said Saltfoss is combining a reactor design heritage proven at Oak Ridge National Laboratory with Korean supply chains, and that the combination lets the company credibly deliver a first-of-a-kind plant. The conceptual design was completed in 2025 after about six years of development, so the notification arrives with a paper design and no hardware.

Part 53 is the reason the timing is interesting. The framework allows reduced and customizable staffing, remote operations and factory fuel loading into manufactured reactors, along with first-of-a-kind licensing provisions that carry standardized design benefits. Those provisions were written for technology that does not look like a conventional land-based plant, and a reactor built in a shipyard and towed to a site is about as far from that template as a commercial design gets. Saltfoss is betting that a rule built to be technology-inclusive can absorb a vessel.

Whether it can is untested, because the commission has not reviewed a maritime design under the new rule. The agency’s page also says Part 53 drops the single failure criterion from the older Part 50 rules and the traditional aircraft impact assessment, substituting a probabilistic and risk-informed approach. Any hull-based safety case would be argued in those terms, with the molten salt’s gravity-drain behavior doing much of the work.

Samsung Heavy Industries and the Korean supply chain

The industrial plan splits the work across two countries. Barge manufacturing stays with Samsung Heavy Industries in South Korea, which Saltfoss lists as a partner alongside KHNP for nuclear operations, KEPCO NF and GS E&C for fuel licensing and production. Saltfoss describes a dual-hub model in which Korean shipbuilding and nuclear supply chains combine with American participation in reactor payload construction, fuel loading and final power plant integration at U.S. facilities.

Korea is also expected to host some early commercial deployments outside the United States, so the company says Korea’s National Safety and Security Commission will be kept aligned with its American application path. In September 2026 the Korea Atomic Energy Research Institute signed a two-year research and development contract worth about 3 billion won, roughly $2.3 million, covering fuel-grade fluoride salt preparation, fuel fabrication, a natural-circulation test loop and high-temperature corrosion testing, according to World Nuclear News. KAERI said the deal transfers no ownership of its molten salt reactor technology.

The company’s timeline has also moved. When the Danish firm changed its name from Seaborg to Saltfoss in April 2025, it said the first reactor was targeted for the first half of the 2030s, with series production from the mid-2030s, after earlier plans for commercial production from 2028. Whether a 2027 engagement plan can hold a schedule that has already slipped once is the open question for the American review.

This article was produced with the assistance of AI and reviewed by Morning Overview editors prior to publication.

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