America Just Signed a Deal to Put Reactors on Ships

On October 12, the American Bureau of Shipping and the U.S. Department of Energy's Office of Nuclear Energy signed a memorandum of understanding to put commercial nuclear power on the water. The agreement covers floating nuclear power plants, nuclear-powered vessels, and the ports, shipyards, and industrial base required to build and sustain them. It is the clearest signal yet that Washington treats the ocean as a platform for the next phase of nuclear energy, not just a shipping lane.

"Advanced nuclear technology is moving from concept to application, and the maritime industry needs to be ready for it," said ABS Chairman and CEO John McDonald when the deal was announced. Assistant Secretary for Nuclear Energy Ted Garrish added that the technology "has the potential to transform the commercial maritime industry and open new markets for American innovation." Bureaucratic agreements rarely make headlines, but this one matters because it is the framework under which floating reactors could move from paper studies to steel hulls.

What the agreement covers

The announced priorities are concept and feasibility studies for two things: floating nuclear energy, meaning reactors on platforms that generate electricity for the grid, and nuclear transportation corridors, meaning the routes, ports, and support systems for reactor-powered ships. ABS will co-manage the Maritime Nuclear Applications Group, formed with help from DOE's National Reactor Innovation Center, and the work will span technical, regulatory, economic, and policy questions.

Related efforts will run through the U.S. Maritime Administration's Center for Maritime Innovation, where ABS serves as secretariat, alongside interagency coordination with the Coast Guard and the Nuclear Regulatory Commission. That coordination is the point: a reactor on a ship touches ship classification, nuclear licensing, port security, and international law at once, and no single agency can clear all of it alone.

The ocean may be where nuclear power finally escapes the economics that have crippled it on land: the shipyard, not the construction site, is the factory.

The reactor that already floats

The United States is not the first to try this. Russia's Akademik Lomonosov, the world's only operating floating nuclear power plant, has been supplying electricity and heat to the Arctic town of Pevek since it entered commercial operation in May 2020. It carries two KLT-40S reactors, each rated at 35 megawatts electric, for roughly 70 megawatts of output, enough to power a city of up to 100,000 people. Pevek has only a few thousand residents, so the plant also feeds regional mining operations. Over its first five years it generated 978 million kilowatt-hours, according to operator data.

The Lomonosov is a non-self-propelled barge, towed into position and connected to onshore infrastructure. It took 17 days to tow 2,640 nautical miles from Murmansk to Pevek. Russia is now building more floating units based on its newer RITM reactor design. The existence proof matters: a reactor can sit on a hull, survive an Arctic winter, and keep a town warm for five years straight.

Why this moment, and why ships

Nuclear propulsion is not new. The U.S. Navy has run reactor-powered submarines and carriers for more than 70 years. Commercial adoption has stayed near zero for a simple reason: reactors were too big, too bespoke, and too legally complicated to put on a cargo ship. Smaller modular designs are changing the first two constraints, and the ABS-DOE deal is aimed at the third.

The technical groundwork has been accumulating quietly. ABS has published classification rules for nuclear power plants on floating platforms. In 2024 it released a study with Herbert Engineering Corporation modeling a high-temperature gas-cooled reactor aboard a 145,000-cubic-metre LNG carrier. It has issued approvals in principle for several nuclear-powered vessel concepts, including a cargo ship propulsion system from an MIT-led maritime consortium. And earlier this month, Hyundai Glovis and U.S. operator Liberty Global Logistics agreed to assess a nuclear-powered car carrier service between South Korea and the United States.

The federal runway was already being paved. On May 7, the Maritime Administration launched an initiative seeking industry input on a U.S.-built, scalable, repeatable, commercially viable small modular reactor for marine transportation, covering design, safety, shipbuilding, workforce, liability, insurance, and port access. In June, the Port of Long Beach agreed to create a trial site for nuclear-powered vessels. In August, MARAD signed a separate agreement with the Port of Corpus Christi to explore reactor integration, port microgrids, and shoreside power.

The hard questions

The licensing picture is clearer than most people assume, and still unresolved in the details. The Nuclear Regulatory Commission has stated it can license maritime reactors under existing regulations. It is pursuing a rulemaking focused on microreactors and a white paper on applying current licensing frameworks to floating facilities and nuclear propulsion. In August, DOE hosted the launch of the International Atomic Energy Agency's ATLAS initiative, which is working toward an international framework covering floating plants and civil nuclear propulsion.

The remaining hurdles are the ones lawyers specialize in: reactor licensing, port access, liability and insurance, crew training, and the split of regulatory responsibility between flag states and coastal states. Shipping is a global industry; a reactor that can only dock in one country is not a business model.

The shipyard bet

The deeper logic of the deal is economic. A recent Energy Transitions Commission report found that similar reactor designs can cost four to nine times more to build in the United States and Europe than in China and South Korea, with financing costs the key factor. Every land-based nuclear plant in the West has become a bespoke megaproject built once, on one site. Ships are the opposite: standardized products built on assembly lines, where the same hull is welded dozens of times and the cost curve bends down with repetition.

A floating nuclear plant is a ship that happens to carry a reactor. Build it in a yard, tow it to a coastline, plug it into the grid, and if the customer stops paying, tow it somewhere else. The natural markets are coastal: remote grids, island nations, desalination plants, port microgrids, and data centers hungry for round-the-clock carbon-free power. That flexibility is exactly what conventional nuclear has never offered.

What this deal is not, yet

It is worth saying what the MOU does not do. It announces no vessel construction project and no deployment schedule. It does not pick a reactor design or a shipyard. It creates the framework for the studies, standards, and interagency agreements that would have to come first. Commercial nuclear power at sea is, for now, a classification society, an energy department, two ports, and a handful of feasibility studies. The gap between this agreement and a nuclear-powered container ship leaving Long Beach is measured in years and in hundreds of millions of dollars. But the direction of travel is unmistakable: the country that industrialized shipbuilding for a world war is now trying to put reactors on the same production line.