BasicsTwo KLT-40S reactors rated at 35 MWe each sit on a 21,500-tonne barge in the Arctic port of Pevek, and they have fed a Russian grid since 2019. That is the entire floating nuclear fleet. One vessel, one country, one operator. The Akademik Lomonosov spent most of its life looking like a Rosatom quirk that the rest of the industry watched from a safe distance.
The distance is shrinking. The IAEA launched its ATLAS initiative in Washington on August 26 and 27, and the US Nuclear Regulatory Commission signed an offshore jurisdiction pact in July. Rosatom, for its part, finished the second reactor for its first repeat-order barge in the past few days. Whether floating plants go mainstream comes down to which clock runs faster: the shipyards or the rulebooks.
Thirteen years for one barge
The Akademik Lomonosov is a non-propelled vessel, 144.4 metres long and 30 metres wide, with a crew of 69. It also took 13 years to build against a plan of four, according to Bellona, which has criticized the project since construction began. That number says more than any megawatt rating, because it is the real price of doing this for the first time.
Reactors: two KLT-40S units at 150 MWt each, about 70 MWe combined
Fuel: low-enriched uranium averaging 14.1% enrichment, on a three-year refuelling cycle
Service record: moored at Pevek on September 14, 2019, commercial since 2020, and more than 1.2 billion kWh delivered by May 2026, per World Nuclear News
Licence: ten years from Rostechnadzor, issued in June 2019 and running to 2029
Grid role: Interesting Engineering reports the barge now carries 60% of the Chaun-Bilibino load, up from 20% in 2020
Russia was not first. The US built the MH-1A on a converted Liberty ship, and it reached criticality in 1967. In the 1970s, PSE&G and Offshore Power Systems planned the Atlantic Nuclear Power Plant, four Westinghouse 1,150 MWe pressurized water reactors floating off New Jersey. It was canceled in 1978. Russia is simply the country that finished.
Baimskaya is the real test
One barge is a demonstration. Four is a business. Rosatom is building four PEB-106 floating units for the Baimskaya copper project in Chukotka, each with two RITM-200S reactors and 106 MWe of output, moored at Cape Nagloynyn. The mine needs about 300 MWe, so three units run while the fourth covers refuelling and maintenance, World Nuclear News reports.
The money is public, which is rare. The World Nuclear Association lists a Rosatom commitment of over RUB 150 billion ($2.1 billion) and an electricity price of RUB 6.45/kWh, about 8 cents, indexed for inflation. That is the first commercial price signal the floating sector has produced.
Hulls: a $226 million contract with China’s Wison (Nantong) Heavy Industries for the first two 19,100-tonne hulls, with the other two at Baltic Shipyard in St. Petersburg
Arrival: the first Chinese hull reached St. Petersburg quietly in March 2026, according to the Barents Observer
Reactors: the first RITM-200S came off the line at ZiO-Podolsk in May 2026, and the second followed this week, completing the PEB-106 set
Schedule: the original contract called for delivery in early 2027, and Rosatom CEO Alexey Likhachev now points to 2028 to 2029
Look at the hull line again. A state nuclear giant with a working reference plant could not find shipyard capacity at home and hired a Chinese yard. If that is the experience of the incumbent, what happens to a startup with a design on paper? For the broader picture of what Beijing builds on its own soil, SMRbrief’s look at China’s SMR program covers the 125 MWe Linglong One on Hainan. Delivery dates here have already moved once and might move again.
Korea, Denmark and the molten salt crowd
Outside Russia, every floating design is still a design. Three are worth knowing.
BANDI-60: a 200 MWt/60 MWe block-type pressurized water reactor from Kepco E&C, paired with an HD Korea Shipbuilding & Offshore Engineering barge, which earned approval in principle from ABS in October 2023
Seaborg CMSR power barge: two to eight 100 MWe compact molten salt reactors per barge, with a 24-year life, backed by a consortium of KHNP and Samsung Heavy Industries
Core Power and TerraPower MCFR: a molten chloride fast reactor adapted for marine use, with Southern Company in the team and a $30 million investment from HD Hyundai in TerraPower since November 2022
Seaborg’s calendar deserves a skeptical read. Its commercial power barge production date moved from 2026 to 2028 in roughly a year, and nothing found in this research shows a finished prototype, so treat the 2026 prototype date as stale. Core Power claims floating plants would cost half as much and build 70% faster than land plants. That is a company estimate, and no operating plant has tested it. Every project, deal, company, and regulatory event we cover is logged, verified, and searchable in SMRbrief Pro, where the barge designs sit next to their land-based cousins, which is the comparison that matters when cost claims arrive.
Regulators are moving before the reactors
The paperwork is where the Western push is furthest along. On July 21, the NRC and the newly formed Marine Minerals Administration signed an MOU covering nuclear projects on the Outer Continental Shelf. The MMA only existed from July 10, when Interior merged the Bureau of Ocean Energy Management and the Bureau of Safety and Environmental Enforcement. NRC Office of Advanced Reactors Director Jeremy Bowen said the deal creates “a clear framework for how our agencies will work together”.
US: the NRC also signed an MOU with the Coast Guard in late June, and a draft maritime licensing white paper is targeted for fall 2026, per ANS Nuclear Newswire and Holland & Knight
No applicants: no offshore nuclear project has been approved or proposed on US waters
IAEA ATLAS: 28 member states signed the launch statement, and commercial participants are expected to pay 25,000 euros a year, with waivers available
IMO: the maritime body is revising its 1981 code for nuclear merchant ships, with adoption envisioned for 2030
The hard questions are legal. Who licenses a reactor built in one country, flagged in another and moored in a third? Which state answers for the spent fuel? Bellona also raises the security angle: a floating plant can sail away from a threat, but a reactor tied up at a remote mine is a conspicuous target with exposed moorings and power connections. Does mobility make a reactor safer in wartime, or just easier to find?
What mainstream would take
Three things have to happen, and none has yet. A second Russian generation has to run at Baimskaya. A customer outside Russia has to sign. And a licensing route has to exist that a lender will underwrite. The first is a shipyard problem, the second a commercial one, and the third is what ATLAS is for.
Grid interconnection waits of five to ten years in some regions, covered in SMRbrief’s piece on how SMRs could solve the data center energy crisis, are the kind of problem a factory-built plant delivered by tow is meant to sidestep. The pitch remains a pitch. No floating unit has been sold to a buyer of that kind.
PEB-106 lead unit: reactor and turbine installation at Baltic Shipyard, with delivery guided to 2028 to 2029
NRC white paper: the draft maritime licensing document due this fall
Lomonosov licence: the 2029 expiry, a natural test of whether Rostechnadzor and Rosatom treat the barge as a permanent asset
IMO code: the 2030 target for the nuclear merchant ship rules
First foreign buyer: Rosatom is marketing a 100 MWe export unit with a 60-year life, and no named customer turned up in this research
The Lomonosov’s licence and the first PEB-106 delivery land in the same year. If the new barge arrives on time and the old one gets renewed, floating nuclear stops being a curiosity. If either slips, the next question is whether the West’s shipyards can do better than Russia’s did. Which side of that bet would a utility take?