The heightened awareness of the climate crisis and the shipping industry’s zero-carbon goals have led the Norwegian shipyard Ulstein to suggest how nuclear power can contribute to the electrification of shipping. A perhaps controversial proposal, here specifically targeted the niche segment of expedition cruises, which is characterized by often having to operate in some of the most remote parts of the world.
The Norwegian shipyard Ulstein is known in the maritime industry for being innovative. It was Ulstein who launched the X-Bow back in 2005. A concept that has since been followed up with the stern concept X-Stern, which together significantly has changed the way a ship’s hull can be constructed and appear.
In 2008, the shipyard’s development department also began to look at the possibilities of reintroduce nuclear power as a fuel in commercial civilian shipping. Something that with the exception of a single Russian ice-breaking multipurpose container ship, has not existed in civil shipping since the 1950s and 1960s, when the United States and West Germany each introduced their own nuclear-powered merchant ship.
However, at that time 15 years ago, it was a very internal project at Ulstein, or in a sense of communication strategy, a very introverted project. The public in 2008 was not yet considered ready to receive or relate to a propulsion alternative that by many was considered highly controversial. But it is now, were the climate crisis and shipping’s transition to zero-carbon is omnipresent in society and in the shipping industry, says Øyvind Gjerde Kamsvåg, Chief Designer at Ulstein.
“As a newbuilding yard, we always want to explore new and exciting technologies. We had the first thoughts about the Thor Project in 2008, but we had a feeling that it politically was not the right moment to go out with it to a wider public. But now we believe it is, with the climate agenda that has created a momentum for also to talk about nuclear power as a fossil-free alternative in shipping”, explains Øyvind Gjerde Kamsvåg.
Molten-Salt technology
The Thor Project, he refers to, is Ulstein’s combined shipping and electrification infrastructure-concept, based on nuclear power, which the yard launched in the spring 2022. The name Thor partly refers to the god Thor in Norse mythology but also refers to the element thorium, which originally actually also was named after the god Thor by the Swedish chemist who discovered the radioactive metal in 1828.
Ulstein wants to combine the use of thorium with the new generation of small and compact Molten-Salt reactors, which are currently under development and commercialization. The Molten-Salt technology eliminates the risk of meltdown, which together with the waste problem, constitute the main challenges in nuclear power.
Today, however, thorium is not used commercially in nuclear reactors, where instead uranium has been established as the preferred fuel. But Ulstein wants to change that if nuclear power is to be used in it civilian shipping, explains Ulstein’s deputy director Jose Jorge Garcia Agis.
“There are several reasons why we want to push development towards thorium instead of uranium. First, it is more energy efficient. Second, thorium is far more difficult to misuse for the production of nuclear weapons than is the case with enriched uranium – and finally the use of thorium, instead of uranium, results in less radioactive waste to be stored”, explains Jose Jorge Garcia Agis.
He emphasizes that Ulstein only sees them self as the designer and integrator in the Thor Project.
“We are currently identifying potential suppliers and challenging them to look away from uranium and instead look towards thorium. Many of those we are looking at are already working with the Molten-Salt reactor technology. And we have at this point also involved the classification societies DNV and Lloyd’s Register in the Thor Project”, explains Jose Jorge Garcia Agis.
Heat battery in an electric driveline
Thorium is present in the subsurface in a variety of geological environments around the globe. The largest occurrences are believed to be in Australia, India, Brazil and the United States, but the element is also present in larger quantities in the subsoil on Norwegian territory.
The Thor Project is not only about nuclear power. It also offers a concept for electrification and charging infrastructure in even the most remote sea areas. In other words, it is a combined zero-emission and infrastructural maritime shortsea electrification project.
When the yard mentions the project, the nuclear power part is toned down. Instead, the proposed thorium-powered Molten-Salt reactor is referred to as a “heat battery”.
“We basically consider the Molten-Salt reactor as a heat battery in an electric driveline. It can deliver 750 degrees of heat over a period of at least 20 years, which in a independent system can turn water into steam, which can then drive a turbine-generator”, explains Øyvind Gjerde Kamsvåg.
From here on in the powertrain, the Thor Project works no differently from any other all-electric ship. There will thus also be large conventional maritime battery packs on board, which will balance the power-consumption and the power-production. The only difference is that a “Thor ship” never has to charge ashore – and never need to bunker fossil fuel.
Full-electric expedition cruise ships
In addition to the perhaps controversial part with the nuclear reactor as power source, the Thor Project relates to the infrastructural challenges, both in relation to a future rollout of nuclear power in civil shipping, and in relation to the general electrification of short-haul shipping.
Thus, only a small number of thorium-powered ships are thought to be positioned strategically, eg. close to the poles in Arctic and Antarctic waters respectively. The ship must therefore only a small number of times throughout its operational lifespan call a port, only to be docked or overhauled. Thus omits the problem that some ports may not want to receive nuclear-powered ships.
In the actual “polar case”, which Ulstein uses to present the Thor Project, the mothership THOR is firmly positioned in a polar sea area where there is a lot of activity with expedition cruise ships. The Thor Project uses a future fully electric Ulstein X-Bow expedition cruise ship, called SIF, i.e., wife of the god Thor, to illustrate the next stage of the concept, which has to do with the infrastructural electrification part. THOR is thus a charging station for non-nuclear fully electric ships in an area where it is not possible to charge from land-based facilities.
This will facilitate completely emission-free cruises around the poles with a fleet of 100% electric expedition cruise ships that would be able to charge locally in the area from THOR. This also removes the risk that expedition cruise customers may not want to sail on board a nuclear-powered ship in a not-so-distant zero-carbon future.
Ulstein has also in the case equipped THOR with a remotely controlled or perhaps even autonomous drone vessel that transfers the power cable from THOR to the full-electric ships to be charged. In the concept vision shown, THOR is also a permanently stationed ship at the Arctic or Antarctic equipped as a base for oceanographic or for example climate-related research.
But according to Øyvind Gjerde Kamsvåg, the concept must also be seen in a wider geographical perspective. That is, rolled out in other places where there may be a need for charging fully electric ships, but where there is no realistic possibility of charging ashore. That could be in certain remote sea areas, where the fishing industry in a zero-carbon future will operate full-electric trawlers and factory vessels.
DISCLAIMER: The above article is based on a visit and interviews at the Ulstein shipyard in Ulsteinvik (Norway) in autumn 2022 as part of a press tour organized by Blue-C. This is an edited English version of the original Danish article that appeared in Søfart in October 2022.
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