COLUMN | Going nuclear: Allseas and modular reactors via K-19; Nauru and the Metals Company; Core Power and US shipbuilding [Offshore Accounts]

This year marks the seventieth anniversary of the launch of the world’s first nuclear-powered submarine, the US Navy's USS Nautilus, which entered service in 1955. For submarines, which require great endurance, the longest possible time hidden safely underwater and stealth, the benefits of nuclear power are obvious.

Not so much in offshore, surely?

Wrong!

Allseas seizes the technological moment

Last week, Swiss-headquartered, Heerema family-owned offshore construction company Allseas announced it was going nuclear. Allseas says it has launched an ambitious five-year plan to design, develop and deploy a small modular reactor (SMR) tailored for integration into offshore vessels and for onshore use.

This has the potential to be a game-changer in two key areas – offshore construction, where Allseas operates its power-hungry flagship Pioneering Spirit, capable of the installation or removal of platform topsides weighing up to 60,000 tonnes and jackets of up to 20,000 tonnes, but also in deepwater subsea mining, where Allseas is the world leader with its converted drillship, now a subsea mining mothership and polymetallic nodule collection vessel, Hidden Gem.

Hidden Gem is the only vessel with a proven track record of the commercial-scale extraction of manganese- and nickel rich nodules after successful pilot tests in the Clarion Clipperton Zone (CCZ) in the Pacific Ocean in 2022, safely collecting 3,000 tonnes of polymetallic nodules and transporting them to the surface from over 4,000 metres of water depth.

More hope than results so far

Unfortunately, the successful deployment of nuclear power in civilian vessels on a wide scale is rather like England winning the football World Cup, the release of the full Jeffrey Epstein files in the US, or Vladimir Putin being bumped off.

You think it could happen, you don’t know when it will happen exactly, and every time it seems close to happening, it spectacularly fails to occur, and everyone who predicted that it would occur looks rather foolish.

Why nuclear?

Before the advent of nuclear power, submarines relied on large banks of lead-acid batteries that required nearly constant attention from crews, and which required charging by returning to the surface to run the vessel’s diesel generators. On the surface, a submarine was extremely vulnerable, as it was not intended to remain exposed above the water for extended periods.

Hydrogen was generated both when the batteries charged and were discharging, creating an explosion risk. The gas had to be vented through the hull, and if the ventilation system failed, then the submarine would be lost.

Oh, and the battery cells would generate toxic chlorine gas if seawater leaked into them, potentially killing everyone onboard.

The loss of the German submarine U-1206 off the coast of Peterhead, Scotland in April 1945 is a case in point. The untrained captain used the Nazi high-tech toilet incorrectly and a wrongly opened sanitary valve led to seawater and sewage contacting the batteries below, filling the sub with chlorine and forcing it to the surface, where it was attacked by British planes.

Four sailors died and U-1206 was forced to surrender by its excrement-soaked captain, Karl-Adolf Schlitt, who lived to the ripe old age of 90, but probably avoided all unfamiliar toilets thereafter.

Anyone who thinks nuclear power is dangerous should spend some time at sea in a First or Second World War-era sub.

Six nuclear-powered navies

USS Nautilus was followed by the Skate-class of submarines, which were powered by single pressurised water reactors (PWRs), and then in 1960, the US Navy launched its first nuclear-powered aircraft carrier, USS Enterprise, which was powered by eight Westinghouse reactor units.

A cruiser, USS Long Beach, followed in 1961, powered by two of these early reactors.

Remarkably, Enterprise remained in service to the end of 2012 with an impeccable nuclear safety record. Today, the US Navy has ten Nimitz-class aircraft carriers and one Gerald R. Ford-class carrier in service, along with 68 other nuclear vessels, mainly submarines.

France is the only other power with a nuclear-powered aircraft carrier, as then-Russian President Boris Yeltsin cancelled Russia’s plans for one in 1992, but Russia does have one nuclear-powered cruiser in operation.

American nuclear submarine power technology was shared with Britain, which currently has 12 nuclear-powered submarines. Royal Navy subs were first fitted with Rolls-Royce built variants of Westinghouse reactors, but now feature reactors of Rolls-Royce’s own design.

The company has been trying to sell its SMRs for civilian use under the slogan, “Clean, affordable energy for all.”

The French, Russian and Chinese navies developed their own reactors, and India launched its first nuclear submarine in 2009, the 6,000DWT INS Arihant, which was finally commissioned in 2016.

K-19: the "widowmaker"

The Soviet Union is the main reason nuclear power developed such a terrible reputation in the 1980s. The USSR developed both PWR and lead bismuth-cooled reactor designs.

With typical Soviet disregard for safety and human life, efforts to build nuclear submarines in the USSR resulted in five incidents where reactors were irreparably damaged and many others resulting in radiation leaks and radiation sickness for crew.

Overcoming the perception that all nuclear reactors at sea are like Soviet reactors is the biggest struggle Allseas, along with other maritime nuclear players like Core Power, will have to overcome.

There were more than 20 radiation fatalities in the Russian nuclear submarine fleet, including the horrible events on the submarine K-19 in an accident at sea in 1961 caused by a cooling failure in the PWR. This catastrophe was immortalised/fictionalised in the Harrison Ford and Liam Neeson film of the same name and resulted in at least eight deaths from acute radiation syndrome (ARS) whilst the crew tried to recover the situation.

Nine Soviet submariners died of ARS aboard K-27 in 1968 in another reactor coolant failure at sea, this time in an experimental lead bismuth-cooled reactor.

Then, in 1985, K-431 was being refuelled with enriched uranium at a base near Vladivostok when a major steam explosion occurred, due to incompetent removal of the reactor lid and control rods. This blast killed ten naval personnel and led to many more crew and firefighters being exposed to dangerously high levels of radiation, with ten suffering ARS.

Eight months later, the reactor in the Soviet power station in Chernobyl melted down, capping the USSR’s nuclear notoriety.

Apart from reactor accidents, fires and other incidents have resulted in the loss of two American and four Soviet nuclear-powered submarines, another four of which also had fires resulting in loss of life.

In the US, UK, French and Indian navies, there has never been a nuclear plant accident on a nuclear-powered warship, and for China, statistics are not available. Strange that.

The loss of the Russian Navy nuclear-powered submarine Kursk on August 12, 2000 in the Barents Sea, during the first major Russian naval exercise in more than 10 years, resulted in the death of all 118 personnel on board.

President Putin’s staff forcibly sedated a crewmember’s grieving mother at the press conference, setting the tone for the following quarter century of his rule.

Any company putting nuclear reactors at sea has first to overcome the Soviet safety concerns, and fears about the completely unrelated Fukushima disaster, even though the contemporary nuclear track record is actually now much better.

Icebreaking in the Arctic

The second category of vessel where nuclear power has been used is icebreaking, where the power requirements for breaking three-metre thick, multi-year ice are best solved by nuclear, and where the availability of fuel in the unpopulated and extremely cold Siberian coast has been a major issue.

The nuclear-powered fleet of Russian energy company and ship operator Rosatom consists of six icebreakers and one freighter, and it has increased the Arctic navigation season from two months to ten months.

Subsea mining in the Pacific

Similar logistics challenges will exist in the Pacific for subsea mining, if and when pioneer the Metals Company finally receives regulatory approval for its plans to hoover up polymetallic nodules from the CCZ using Hidden Gem.

As Philip Gales has highlighted, the remote location of the nodule fields of the CCZ makes for a logistical nightmare. Puerto Vallarta in Mexico is the closest international airport, 910 nautical miles from the Metals Company’s NORI-D licence zone, and just under four days sailing in a supply vessel at 10 knots.

I would expect a drillship like Hidden Gem will typically use fifty or more tons of marine gas oil a day operating in DP. Thus, large quantities of fuel will be burnt simply carrying fuel to the mothership, raising support costs.

The location is beyond the 540-nautical-mile range of both Sikorsky and Airbus commercial helicopters and crew change will be hard, let alone the merry-go-round of bulk carriers taking the recovered nodules to the smelters.

The nodules from the experimental collection were refined by partner PAMCO in Hachinohe in Japan, 23 days sailing away from the NORI-D licence at 10 knots, another logistical nightmare.

Fitting a nuclear power plant to Hidden Gem would thus remove much of the logistical issues of supplying the vessel with fuel and would enable it to stay on location longer, even if the wider problems of crew change and nodule transportation to the smelter remain unresolved.

Nauru and the Metals Companies go nuclear

If Allseas is looking at going nuclear literally, its customer the Metals Company has also gone metaphorically nuclear with the International Seabed Authority (ISA) as we reported in March.

The ISA has currently failed to agree a mining code and so has not granted the Metals Company the authority to proceed with commercial mining activities. This is unsurprising given that the CCZ is home to more than 5,000 species that are new to science and have never been found anywhere else on Earth, according to Matthew Sparkes in New Scientist.

In March, the company decided to ditch its efforts to woo the ISA and turned to President Donald Trump in Washington. Erik Noble, principal deputy assistant secretary of commerce for oceans and atmosphere, reiterated the national security grounds for supporting the Metals Company in a statement released on April 25:

“The United States will lead the world in deep sea mineral extraction, and NOAA is the tip of the spear as we partner with federal agencies and private industry to support the discovery and collection of critical minerals on the sea floor.”

The Metals Company therefore applied for a commercial recovery permit under the US Deep Seabed Hard Rock Mineral Resource Act (DSHMRA), a 1980 law that allows American companies to seek seabed mining licenses.

In April, the company submitted an application to the National Oceanic and Atmospheric Administration (NOAA) for commercial recovery and exploration rights over a 25,160-square-kilometre area in the CCZ, even though the Metals Company is a Canadian company, albeit listed in the US on Nasdaq, although it did register a US-based subsidiary to apply for the permits.

Unfortunately, the NOAA has never actually issued a commercial recovery permit under the DSHMRA before. It has only issued two exploration licenses in its history, to Lockheed Martin, in 1984.

The ISA has stated that any attempt to bypass its process and start commercial operations under the auspices of the US Government and the NOAA would be a violation of international law.

Nauru press release claims breach

Last week, Nauru, the sponsoring state of the NORI-D licence, came a step closer to renouncing the ISA process and to accepting American regulatory approval for commercial activities on the NORI-D licence.

The Government of Nauru and the Metals Company’s subsidiary, Nauru Ocean Resources (NORI), signed a revised sponsorship agreement updating the terms of their agreement signed in 2017 and put out a curiously contradictory press release.

The statement reiterated Nauru‘s commitment to the ISA… but then continued that, “in breach of its obligations under UNCLOS, the ISA has failed to adopt the exploitation regulations and is continuing to unlawfully delay the adoption of these regulations.”

The claim of breach is one that obviously could have legal ramifications for the relationship between Nauru and the ISA.

The statement went on to say that the Government of Nauru and he Metals Company, “acknowledge that unexpected, continued and extended delays at the ISA in adopting the exploitation regulations have impeded NORI’s ability to proceed with its planned application for commercial exploitation activities in the NORI area and breached Nauru’s legitimate expectations as a small island developing state in enjoying its rights as a sponsoring State under UNCLOS.

"The Republic of Nauru acknowledges the recent executive order by US President Trump and the existing US seabed mining code under DSHMRA, which provides a stable, transparent and enforceable regulatory path for industry."

This threat was left hanging, and the language is deliberately opaque, but how long would it be before Nauru walks out of the ISA and accepts NOAA as having the power to permit commercial mining operations to commence?

That would see the non-nuclear Pacific microstate really going nuclear.

Allseas goes Dutch with Delft

Interestingly, Allseas has not chosen to partner with an existing player in the modular nuclear sector, like Rolls-Royce or Westinghouse, or Core Power.

Instead, Allseas has selected high-temperature gas-cooled reactors (HTGRs) in the 25MWe range, due to what the company describes as, “their inherently safe characteristics”:

"This fourth-generation reactor technology generates energy without combustion or emissions. HTGRs are powered by TRISO fuel particles, each representing a sphere with the size of a poppyseed. Each particle contains a uranium oxide core, coated with several advanced protective ceramic layers that securely contain fission products – even under extreme conditions.

"The technology results in passive safety: the reactor self-regulates and remains stable, keeping temperatures well below critical thresholds. In the unlikely event of malfunction, the system automatically cools down and shuts off without the need for active intervention or external cooling.”

The company will partner with Delft University of Technology, which has been working on an inherently safe microreactor based on HTGR technology for more than 10 years. This would seem to slow the process rather than fast tracking with existing technology.

Core Power and US shipbuilding

This Dutch choice must have come as a disappointment to Core Power, the leading proponent of Maritime modular nuclear reactors. Core Power claims to have developed an innovative and safe molten chloride fast reactor, which it says offers unparalleled advantages compared with conventional light water reactors and other advanced reactor concepts.

Unfortunately, despite being backed by some of the biggest names in the maritime world, it has yet to deploy any reactor on a ship.

Like the Metals Company, Core Power now sees Donald Trump's "America first" agenda as an opportunity to tip the competitive landscape in its favour. Nuclear-powered vessels are the one niche area of shipbuilding where American shipyards have a leading track record and where cost is less of an issue.

In a piece in American Journal of Transportation in May and on its website, the company asked, “Can building commercial nuclear-powered merchant ships revitalise the US maritime industry?”

Surprise! It thinks it can, and it made the following argument:

“There is a convergence of technological shifts in the shipping industry and political trends that have opened an opportunity for which a US-flagged nuclear-powered merchant ship is the logical solution.

"At its core, the ‘liberty' initiative is 'a maritime civil program, designed to build large US-flagged nuclear-powered merchant ships along with floating nuclear-power plants. This entails abiding by the complex regulatory approvals, technical requirements and personnel demands that come with a US flag program.”

There does indeed seem to be a convergence of political interests in Washington to use the US Government as a mechanism for companies to gain regulatory advantage over their foreign competitors and to gain access to government funds.

Core Power and the Metals Company are both companies with expensive and risky projects that have struggled commercially. It makes sense for them to seek state aid from the US to achieve their goals, but it also behooves voters, investors, legislators and the rest of the world to be sceptical about these companies' claims.

"Green" subsidies and state handouts for renewables were condemned by those who now seem to think that only new subsidies for American shipbuilding, nuclear power plants and/or critical deepsea mineral mining projects can turn around America’s strategic position relative to China.

Our position remains that adding nuclear to the mix will not help revive American shipbuilding.

Let’s see.

Background reading

One financial analyst on the Seeking Alpha website published a devastating critique of the Metals Company. Nor East Invest wrote that, “I rate TMC a strong sell based on uncertainty and poor future prospects,” and that:

“One of the most pressing concerns for TMC is the mismatch between its lofty billion dollar market valuation and weak balance sheet. As of Q1 2025, TMC reported US$13 million in tangible assets and US$2.3 million in cash, an insufficient number to support deep sea mining.

"The intangible assets of US$43 million are classified as exploration licenses and are just contractual rights issued by Tonga and Nauru to explore specific zones in the CCZ. These licenses do not guarantee commercial rights and cannot be sold off. Their value is entirely speculative.

"Last month, TMC announced a US$37 million dollar strategic investment through a direct stock offering, issuing 12.3 million shares for US$3 each, along with warrants.

"While this transaction boosts liquidity, it dilutes shareholders and allows for future dilution with more warrants. The investment does not address the long-term funding gap, and TMC has not shown positive progress on the commercial exploration permit."