Tag Archives: TerraPower

Ulstein’s Nuclear-powered Thor and its All-electric Companion Vessel Are a Zero-Carbon Solution for Marine Tourism

Peter Lobner

1. Introduction

In June 2022, the Norwegian firm Ulstein (https://ulstein.com) announced their conceptual design of a Replenishment, Research and Rescue (3R) vessel named Thor that will be powered by a thorium molten salt reactor (MSR). This vessel can function as a seaborne mobile charging station for a small fleet of electrically-powered expedition / cruise ships that are designed to operate in environmentally sensitive areas such as the Arctic and Antarctic. Other environmentally sensitive areas include the West Norwegian Fjords, which are UNESCO World Heritage sites that will be closed in 2026 to all ships that are not zero-emission. In the future, similar regulations could be in place to protect other environmentally sensitive regions of the world, thereby reinforcing Ulstein’s business case behind Thor and its all-electric companion vessels.

Ulstein’s Thor MSR-powered vessel (left) and 
Sif electrically-powered expedition / cruise vessel (right). 
Source: Ulstein

2. The MSR-powered Thor charging station

Thor is a 149-meter (500-foot) long, zero-emission, nuclear-powered vessel that features Ulstein’s striking, backwards-sloping X-bow, which is claimed to result in a smoother ride, higher speed while using less energy, and less mechanical wear than a ship with a conventional bow. 

For its R3 mission, Thor would be outfitted with work boats, cranes, a helicopter landing pad, unmanned aerial vehicles (UAVs), unmanned surface vessels, firefighting equipment, rescue booms, a lecture hall and laboratories.

As a charging station, Thor would be sized to recharge four all-electric vessels simultaneously.

Thor.  Source: Ulstein

Thor also could serve as a floating power station, replacing diesel power barges in some developing countries or in some disaster areas while the local electric power infrastructure is being repaired.

Ulstein projects that an operational Thor vessel could be launched in “10 to 15 years.” However, the development and licensing of a marine MSR is on the critical path for that schedule.  

Thor, starboard side views.  Source, both graphics: Ulstein

3. The all-electric Sif expedition / cruise ship

Sif, named after the goddess who was Thor’s wife, is a design concept for a 100-meter (330-foot) long, all-electric, zero-emission expedition / cruise ship designed to operate with minimal impact in environmentally sensitive areas. The ship will be powered by a new generation of solid batteries that are expected to offer greater capacity and resistance to fire than lithium-ion batteries used commonly today.  It will be periodically recharged at sea by Thor.

The ship can accommodate 80 passengers and 80 crew. 

Sif, starboard side view.  Source, both graphics: Ulstein

4. A marine MSR power plant

The pressurized water reactor (PWR) is the predominant marine nuclear power plant in use today, primarily in military vessels, but also in Russian icebreakers and a floating nuclear power plant in the Russian Arctic. 

Ulstein reported that it has been exploring MSR technology because of its favorable operating and safety characteristics. For example, an MSR operates at atmospheric pressure (unlike a PWR) and passive features and systems maintain safety in an emergency. If the core overheats, the molten salt fuel/coolant mixture automatically drains out of the reactor and into a containment vessel where it safely solidifies and can be reused.  You’ll find a good overview of MSR technology here: https://whatisnuclear.com/msr.html

While a few experimental MSRs have operated in the past, no MSR has been subject to a commercial nuclear licensing review, even for a land-based application. Ulstein favors a thorium-fueled MSR. The thorium-uranium-233 fuel cycle introduces additional technical and nuclear licensing uncertainties because of the lack of operational and nuclear regulatory precedents.

Several firms are developing MSR concepts. However, the combination of a marine MSR and a thorium fuel cycle remains elusive. Two uranium-fueled marine MSR design concepts are described below.

Seaborg Technologies

The Danish firm Seaborg Technologies (https://www.seaborg.com), founded in 2014, is developing a compact MSR (CMSR) with a rating of about 250 MWt / 100 MWe for use in power barges (floating nuclear power plants) of their own design (see my 16 May 2021 post). The thermal-spectrum CMSR uses uranium-235 fuel in a molten proprietary salt, with a separate sodium hydroxide (NaOH) moderator.  

A Seaborg Technologies CMSR module could generate 100 MWe. Dump tank shown below reactor. Source: Seaborg via NEI (2022)

Seaborg’s development time line calls for a commercial CMSR prototype to be built in 2024, with commercial production of power barges beginning in 2026. 

Source: Seaborg (2022)

In April 2022, Seaborg and the Korean shipbuilding firm Samsung Heavy Industries signed a partnership agreement for manufacturing and selling turnkey CMSR power barges. 

On 10 June 2022, Seaborg was selected by the European Innovation Council to receive a significant (potentially up to €17.5 million) innovation grant to help accelerate their work on the CMSR.

CORE-POWER and the Southern Company consortium

The UK firm CORE-POWER Ltd. (https://corepower.energy), founded in 2018, began with a concept for a compact uranium-235 fueled, molten chloride salt reactor named the m-MSR for marine applications. This modular, inherently safe, 15 MWe micro-reactor system was designed as a zero-carbon replacement power source for the fossil-fueled power plants in many existing commercial marine vessels.  It also was intended for use as the original power source for new vessels, as proposed for the Earth 300 Eco-Yacht design concept unveiled by entrepreneur Aaron Olivera in April 2021 (see my 17 April 2021 post). The power output of a modular CORE-POWER m-MSR installation could be scaled to meet operational needs by adding reactor modules in compact arrangements suitable for shipboard installation. 

A set of six small, compact CORE-POWER m-MSR modules
could generate 90 MWe. Dump tank not shown. Source: CORE-POWER

In November 2020, CORE-POWER announced that it had joined an international consortium to develop MSRs. This team includes the US nuclear utility company Southern Company (https://www.southerncompany.com), US small modular reactor developer TerraPower (https://www.terrapower.com) and nuclear technology company Orano USA (https://www.orano.group/usa/en). In the consortium, TerraPower is responsible for the fast-spectrum Molten Chloride Fast Reactor (MCFR). CORE-POWER is responsible for maritime readiness and regulatory approvals.

This consortium applied to the US Department of Energy (DOE) to participate in cost-share risk reduction awards under the Advanced Reactor Demonstration Program (ARDP), to develop a prototype MCFR as a proof-of-concept for a medium-scale commercial-grade reactor. In December 2020, the consortium was awarded $90.4 million, with the goal of demonstrating the first MCFR in 2024.  DOE reported, “They expect to begin testing in a $20 million integrated effects test facility starting in 2022. The team has successfully scaled up the salt manufacturing process to enable immediate testing. Data generated from the test facility will be used to validate thermal hydraulics and safety analysis codes for licensing of the reactor.”In February 2021, CORE-POWER presented the MCFR development schedule in the following chart, which shows the MCFR becoming available for deployment in marine propulsion in about 2035.  This is within the 10 to 15 year timescale projected by Ulstein for their first Thor vessel.

Source: CORE-POWER (2021)

5. In conclusion

A seaborne nuclear-powered “charging station” supporting a small fleet of all-electric marine vessels provides a zero-carbon solution for operating in protected, environmentally sensitive areas that otherwise would be off limits to visitors. Ulstein’s concept for the MSR-powered Thor R3 vessel and the Sif companion vessel is a clever approach for implementing that strategy.

It appears that a uranium-fueled marine MSR could be commercially available in the 10 to 15 year time frame Ulstein projects for deploying Thor and Sif.  The technical and nuclear regulatory uncertainties associated with a thorium-fueled marine MSR will require a considerably longer time frame. 

6. For additional information 

Ulstein Thor & Sif


Seaborg CMSR


The Earth 300 Eco-Yacht Could Serve as a Prototype for De-carbonizing the World’s Commercial Marine Transportation Fleets

Peter Lobner

In early April 2021, a flurry of articles described the beautiful, futuristic, nuclear-powered eco-yacht conceived by entrepreneur Aaron Olivera, CEO of Earth 300 (https://earth300.com), and introduced in Singapore as his concept for a signature vessel for conducting environmental research and raising environmental awareness around the world.

Aaron Olivera and the Earth 300 eco-yacht. Source: Archyde.com

This sleek yacht is almost 300 meters long with a prominent cantilevered observation deck near the bow and a 13-story glass “science sphere” amidships. Olivera describes this vessel as follows: 

“Earth 300 it is an extreme technology platform for science, exploration and innovation at sea. Its mission is to ring the ecological alarm on a global scale and combat climate change. Using technology it will quickly scale and deploy solutions to market. Its ultimate ambition is to inspire billions of people to contribute to the preservation of our shared planet, and becoming a sustainable and future worthy civilization.”

The ship’s design was developed by Ivan Salas Jefferson, founder of Iddes Yachts (https://iddesyachts.com), in collaboration with the Polish naval architecture firm NED (https://www.ned-project.eu). Mikal Bøe is the CEO of London-based Core Power (https://corepower.energy), which will supply the next-generation, inherently safe marine molten salt reactor (m-MSR) power plant, using MSR technology developed by the US nuclear company TerraPower (https://www.terrapower.com) that was co-founded by Bill Gates. 

The general arrangement of the ship’s inhabited spaces.
Source: Earth 300

The current design has taken six years and $5 million to develop.  Earth 300 reports that it is making good progress toward getting an Approval in Principle (AIP) from RINA (formerly Registro Italiano Navale). RINA is a founding member of the International Association of Classification Societies (IACS), which promotes safer and cleaner shipping worldwide.  The AIP is a framework used by RINA to review and approve innovative and novel concepts that are not covered by traditional classification prescriptive rules, so that a level of safety in line with the current marine industry practice is provided. The AIP process is a risk-based approach to classification that allows for new designs and novel concepts to be validated with safety equivalencies.

Following the AIP, Earth 300 should be able to request construction quotes from one or more shipyards, likely in Europe and/or South Korea. The ship will be equipped with 22 laboratories for about 160 scientists, cutting-edge artificial intelligence (AI) and robotics systems, and facilities for operating helicopters and submersible and semi-submersible vehicles.  Earth 300 executives reportedly estimated that the total construction cost will be between $500 million and $700 million.

The observation deck is located atop the bow section of the ship.
Source: Earth 300
Foredeck helipad and hangar for a helicopter. Source: Earth 300
The sphere houses a “science city” where most of the shipboard research facilities are located.  Source: Earth 300

Once in operation, the ship is certain to command attention wherever it goes, as a recognizable symbol for environmental protection.  This notoriety may be enough to attract wealthy tourists willing to pay $3 million for a 10-day cruise in the 10 luxury suites with private balconies and accommodations for personal staff in a separate set of cabins.  That sort of money will buy a lot of selfies, instagrams and some durable bragging rights. 

The ship is designed to accommodate 425 people, including the ship’s crew, scientists, and the group of wealthy tourists paying full price. In addition, it has been reported that Olivera envisages inviting groups of other people to travel at a lower price or even for free. For example, 10 suites would be made available to what Olivera calls Very Interesting Persons – people from all walks of life who would bring unique experience or knowledge to the voyage. In addition, some lucky artists, explorers and students may travel for free.

While I’m impressed with the general concept of this ship, I feel that the primary benefit of this grand vessel can’t be to serve as a mobile marine “mixer” for a few very wealthy individuals to associate with scientists, some elite Very Interesting Persons, and a patchwork of others interested in environmental protection.

Like the 3 AM infomercial says, “But wait, there’s more.” Research performed aboard the ship would be “open source” and shared with other research efforts around the world.  That’s great, but more information is needed on the meaningful research programs that would be conducted on the Earth 300 vessel in segments that match the schedule and route of what is essentially a cruise ship.  It seems that a much less expensive dedicated vessel could accomplish the same research while not serving as an environmental sideshow on a cruise ship.

With the ship scheduled to launch in 2025, the vessel itself will be ready many years before the planned marine molten salt reactors (m-MSRs) have been developed and approved by the appropriate nuclear and marine regulatory agencies.  Therefore, it is likely that the vessel will be designed to operate initially with a conventional marine power plant running on synthetic “renewable” fuels.  This isn’t exactly a big step in the right direction for helping to reduce the carbon emissions from worldwide commercial marine transportation.

Like the 3 AM infomercial says, “But wait, there’s more,” or at least, there should be.

Core Power, the developer of the m-MSR planned for the Earth 300 vessel, is designing their 15 MWe inherently safe micro-reactor system as a zero-carbon replacement power source for the fossil-fueled power plants in many commercial marine vessels. On their website, Core Power presents the following business case:

“Over the next few decades as many as 60,000 ships must transition from combustion of fossil fuels to zero-emission propulsion. The UN’s maritime agency IMO has mandated with unanimous approval from 197 countries that shipping must reduce emissions by 50% of the 2008 total, before 2050. This means an actual emission reduction of almost 90%, by 2050. MSR technology being developed by the consortium could achieve that goal, by powering production of green sustainable fuels for smaller ships and providing onboard electric power for large ships, with zero emissions as standard.”

A set of six small, compact Core Power m-MSRs could generate
90 MWe (about 120,000 hp). Source: Core Power

I think it is actually fortuitous that the Earth 300 vessel will start its life as a fossil-fueled vessel.  From this starting point, Earth 300 will be at the vanguard of a new generation of inherently safe marine nuclear power system development and deployment.

Converting the Earth 300 vessel to nuclear power will move the discussions on commercial marine nuclear power from the academic domain, where it has languished for many decades, to the commercial marine nuclear safety regulatory domain, which has been inactive for decades and likely is not prepared for this new applicant.  By being first in line, Earth 300 and Core Power take on substantial licensing risk that certainly will add to the time and cost of their nuclear licensing efforts.  However, they are in unique positions as a reactor supplier and a vessel operator to help shape the licensing dialogue pertaining to the use of inherently safe micro-reactors in marine vessels, and the worldwide operation of vessels using such reactors.

The experience gained from converting Earth 300 from fossil to nuclear power will de-risk the nuclear power conversion process for the entire marine transportation industry.  

  • Regulatory precedents will have been established for the reactor designer and the vessel operator. 
  • The conversion experience will yield many metrics and lessons learned that will help in planning and executing subsequent conversions. 
  • Ports around the world will be on notice that commercial nuclear-powered vessels once again are a reality and appropriate port-specific nuclear safety plans may be required

In this role alone, Earth 300 will create a path for the commercial marine transportation industry to meet the IMO’s 2050 emission goal.  This would be a truly substantive accomplishment that will far outweigh the ship’s public relations accomplishments as a symbol of environmental protection and showcase for environmental research.

I hope Aaron Olivera gets the support he needs to build the Earth 300 ship and subsequently convert it to nuclear power.  At one level, the ship is a grand gesture.  On another level, the nuclear powered ship is a substantive step toward a future with zero-carbon commercial marine transportation.

For more information