Gen IV nukes could power next-gen cargo ships

Lloyd's Register and nuclear startup Core Power are joining forces with shipping company Maersk to study how to update regulations as part of an effort to introduce Gen IV nuclear reactors to power the next generation of zero-carbon-emission cargo ships.

On July 21, 1959, a new era in commercial shipping appeared to dawn as the NS Savannah slipped down the way and into the water at New York Shipbuilding Corporation in Camden, New Jersey. The deliberately futuristic-looking passenger freighter was built at the then astronomical cost of US$46.9 million (US$495 million in 2024) as part of the Eisenhower administration's Atoms for Peace program.

The Savannah was never meant to be economical to operate. It was a demonstrator vessel designed to show how nuclear power could be used for peaceful commercial operations. Despite being a remarkable piece of nautical engineering and a beautiful example of atomic age aesthetics complete with luxury accommodations, it only served from 1962 to 1972 before being laid up and she is now a museum ship in Baltimore, Maryland.

To date, only four nuclear cargo ships have been built and only one, the Sevmorput, remains in service in Russia to serve Arctic trade routes. Despite an initial burst of optimism, the market for civilian nuclear powered vessels simply never materialized. The life-cycle costs proved to be too high to compete with conventional ships, the highly trained crew needed to run such ships were too costly, and the port infrastructure for nuclear vessels didn't exist.

But the biggest blow were the complex and uncertain domestic and international regulations and license requirements that made nuclear cargo ships a very risky investment.

Today, that's changing in the face of mandates for shipping to go carbon neutral by 2050. It's estimated that the shipping industry burns 300 million tonnes of fossil fuels per year in the form of heavy diesel, producing 3% of global greenhouse gas emissions. While other alternatives are being looked at, a number of companies see nuclear power in the form of Gen IV reactors as the most practical solution.

There are about 200 nuclear reactors operating on 160 naval ships and submarines around the world, but, though they have an excellent safety record, these military reactors aren't suitable for civilian ships due mainly to insurance problems. Therefore, companies and consortia like America's TerraPower, Britain's Newcleo and Core Power, Norway's NuProShip, Italy's Fincantieri, and Japan's Imabari Shipbuilding are all looking at advanced reactors for large container ships and similar craft.

These reactors are similar to the advanced modular reactors and others being developed for shoreside use. Specifically, the favored models are the thorium-fueled molten-salt reactor, where thorium is dissolved into the salt coolant; the lead-cooled fast reactor, which replaces water coolant with molten lead; and the helium-gas-cooled pebble-bed reactor that uses balls of tristructural isotropic (TRISO) nuclear fuel, which consists of layers of uranium, carbon, and ceramic.

What all of these reactors have in common is that they don't need to be sealed in pressure vessels like most commercial reactors. They are much less complex, run at lower temperatures, and are inherently safe because the nuclear reaction is self-regulating and, in the case of the salt and lead reactors, the coolants solidify before any damage can be done in the case of an accident.

There are any number of technical hurdles to be overcome, but for the Lloyd's-led group the most vexing is regulation. For this reason, the partners are not only looking at how to make the best technical and business case for Gen IV nuclear cargo ships, but also how to square things with existing regulations or how to update them and make such craft a major player inside the next 15 years.

"The initiation of this joint study marks the beginning of an exciting journey towards unlocking the potential of nuclear power in the maritime industry, paving the way for emissions-free operations, more agile service networks and greater efficiency through the supply chain," said Nick Brown, CEO, Lloyd’s Register. "A multi-fuel pathway to decarbonizing the maritime industry is crucial to ensuring we as an industry meet the IMO’s emission reduction targets and nuclear propulsion shows signs of playing a key role in this energy transition."

Source: Lloyd’s Register