Nuclear Energy-Powered Cargo Ships Are Trying to do a Comeback

By Sophia Francise

June 10, 2023
cargo ships at the port

In view of the difficult problem of decarbonization, some shipping companies are reconsidering a polarising solution: nuclear fission.[1]

President Eisenhower dreamed of creating a ship that would symbolize peace, powered by the power of the atom. The vessel would travel under the stars and stripes, carrying only US officials and goodwill. 

The US military expanded its nuclear weapons arsenal and launched the world’s first nuclear submarine in 1954. Eisenhower agreed to authorize a nuclear-powered merchant ship to carry cargo and passengers. 

The Savannah, capable of hauling 14,000 tons of cargo, entered service in 1962.

Its reactor was encased in 4 feet of concrete, steel, and lead and had an 8-foot-long table topped with white marble and an early CCTV system.

In the passenger lounge, there was an 8-foot-long table topped with white marble and an early CCTV system.

Shipping is a difficult industry to decarbonize, but nuclear energy produces zero emissions at the point of use, however, nuclear hubris is a dangerous mistake that should be avoided.

Shipping accounts for 3% of all greenhouse gas emissions and is seen as a difficult industry to decarbonize.

The NS Savannah failed in its first year at sea, dumping 115,000 gallons of radioactive waste into the ocean. 

Other countries also tried to make nuclear merchant ships work during the 20th century, such as West Germany’s Otto Hahn. It was refused entry to some ports and the Suez Canal on safety grounds. 

The Mutsu, a Japanese vessel, suffered a minor failure in its reactor’s radiation shielding in 1974, causing outcry and blocking the ship’s return to port for several weeks. 

As of 2023, there is only one active nuclear-powered merchant ship in the world, the Russian-built NS Sevmorput. It is tiny compared to most fossil-fuel-powered container ships and has been plagued by breakdowns. 

However, nuclear-powered submarines, aircraft carriers, and icebreakers have been sailing the oceans for over half a century with relatively little fuss. 

Are We Ready to Embrace Nuclear Cargo Ships?

Given the urgency of reducing emissions, it is time to embrace nuclear cargo ships finally.


A group of organizations in South Korea signed a memorandum of understanding to develop nuclear-powered merchant ships with small modular reactors. Still, they have yet to reveal much about the project.

“We believe it is too early to mention details on the tangible results of this partnership,” Hojoon Lee, a spokesperson for HMM, one of the shipping lines involved, tells WIRED. “We still have a long way to go to achieve the commercial viability of nuclear energy sources.”

NuProShip (Nuclear Propulsion of Merchant Ships) is a project in Norway. They have compiled a short list of six possible reactor designs that could work in a demonstrator’s vessel. 

The South Korean and Norwegian efforts are considering molten salt reactors, which involve dissolving nuclear fuel into molten fluoride salts.

These reactors first operated in the 1960s and are nothing new, but technical issues have hampered their widespread rollout. 

Proponents say such reactors could have serious safety and efficiency advantages over other types, such as pressurized water reactors.

Nuclear fuel is incredibly energy dense and can be drained to prevent a runaway reaction.

Ondir Freire and Delvonei Alves de Andrade, who also works at Brazil’s Nuclear and Energy Research Institute, have published multiple papers on the history and possible future of nuclear-powered merchant shipping. 

They have a solution in mind: small reactors that can be detached from one ship and installed in another or in some other kind of facility. 

Despite the high upfront cost of building a new reactor, switching from dirty fossil fuels to nuclear ones would be cost-effective in the long run.

Nuclear reactors can operate for many decades, but it could be a problem for ship owners. 


Alves de Andrade argues that public perceptions of nuclear energy and technology remain dominated by the Chernobyl and Fukushima disasters and concerns around the radioactive waste. 

While many nuclear reactors operate at sea, they tend to be on vessels with the highest security in the world.

Commercial ships are occasionally subject to piracy and accidents, making them unlikely to be met with enthusiasm.

Switching to a world where nuclear-powered vessels are commonly welcomed at commercial ports is not trivial.

There needs to be more of a regulatory framework to define how nuclear ships would operate globally in the commercial sector, including detail on who would bear responsibility for any mishaps. 

There are six “decade-long problems” regarding nuclear vessels that the International Maritime Organization (IMO) and other agencies would have to sort out if nuclear-powered commercial ships were ever to become widespread. 

The crews on nuclear ships would require special training and expertise, which raises the cost of running such vessels, is it worth dealing with all these challenges, given the need to decarbonize right now?

 The Norwegian NuProShip project won’t convert its first demonstrator ship until 2035, and other low- or zero-emissions fuels are already being deployed in vessels.

However, nuclear technology may eventually dominate, as the original Savannah was a technological pioneer.

As President Eisenhower found out, dreams are one thing, then there’s the future.


  1. Chris, Baraniuk, ‘Nuclear-Powered Cargo Ships Are Trying to Stage a Comeback’, Wired, 9 June 2023,[]