Headwinds may scupper shipping’s nuclear ambitions

Powering maritime vessels with nuclear reactors will reduce emissions and remove the need for expensive bunkering, but regulatory and safety concerns may sink any projects before they are realized.

Nuclear-powered aircraft carrier USS Enterprise spells out E=MC2 x 40 to mark 40 years of nuclear naval ships in 2012 (Source: Reuters/Navy handout)

Related Articles

Nuclear-powered shipping has been posited as an option as reactors become safer and more compact for an industry striving to decarbonize.

But, regulating a vessel that sails international waters, passing from port to port, with a working nuclear reactor onboard will be one of the greatest challenges to commercial adoption.   

Today, there are approximately 160 ships and sea-faring vessels operating worldwide that are powered by more than 200 nuclear reactors, according to the World Nuclear Association, mostly military submarines but also aircraft carriers and icebreakers as well as research vessels.

The first nuclear-powered submarine, the USS Nautilus, went to sea in 1955, followed by the USS Enterprise aircraft carrier – powered by eight Westinghouse reactors – in 1960. By 1962, the U.S. Navy had 26 nuclear submarines operational and 30 under construction.

Unfortunately, current nuclear-powered vessels do not provide helpful examples for commercial roll out as they are primarily military or government applications.

While the military has used nuclear-powered vessels for decades, the technology and/or regulatory conditions surrounding their use is not transferrable to the commercial shipping sector, according to Domenic Carlucci, ABS Vice President, Global Government Services who, before his position at the ABS, served as Nuclear Surface Warfare Officer in the U.S. Navy.

“Many people say that we’ve done this before, but the nuclear Navy is a not a good commercial case study,” says Carlucci.

“The nuclear Navy is a very specific type of reactor with a specific type of fuel that has limited applicability and therefore will most likely not be used in the commercial sector. So, it doesn't really offer a blueprint. In many respects, maritime commercial nuclear applications will require new advanced reactor technology.”

Keeping it safe

Demonstrated safety is at the very heart of nuclear regulation, and installing a reactor in a pitching and rolling vessel in the middle of the ocean is a hard sell for regulators and, maybe more importantly, port authorities.

Concerns begin with the question of what happens when a nuclear-powered reactor sinks to the bottom of the ocean.

A total of six nuclear submarines have been lost to accidents since 1963, according to the International Atomic Energy Agency (IEAE) - four by the Soviet Union and two by the U.S. Navy.

While environmental agencies continuously monitor known sunken nuclear vessels to track potential long-term impacts, studies have found localized radionuclide contamination around the site but with minimal evidence of wider dispersal.

Despite evidence that suggests sunken nuclear-powered vessels release very little radiation into sea water, developers are looking at next generation reactors built to be less mechanically complex than previous generations, and inherently safe, fed with modern, accident tolerant fuels (ATFs) to ease concerns surrounding mobile, seafaring reactors.

The Norwegian project NuProShip 1 (Nuclear Propulsion of Merchant Ships) is studying the feasibility of all known small modular reactor (SMR) designs and, after applying 37 selection criteria, the project ended up with three Gen IV reactor designs, two of which are based on TRISO fuel.

TRISO (TRi-structural ISOtropic particle fuel) is made up of a uranium, carbon, and oxygen fuel kernel (each about the size of a poppy seed) encapsulated by three layers of carbon- and ceramic-based materials that protect against the release of radioactive elements.

Such particles cannot melt in a commercial high-temperature reactor, and would be stable if scattered on the ocean floor.

“The reason we go all the way to TRISO fuel is simply to kill the politics before it starts,” says NuProShip 1 project manager Jan Emblemsvåg, professor at NTNU Department of Ocean Operations and Civil Engineering.

“TRISO is encased in ceramic and insoluble, and while radioactive substances in seawater have been shown to have very little impact, in the public mind it is a very different story.”

Licensing and Regulatory Challenges for Nuclear Powered Shipping *

(Click to enlarge)

* Participants were asked to score each specific topic associated with licensing and regulatory requirements based on how large a barrier they perceived it to be for commercializing Commercial Maritime surface vessel Nuclear Propulsion

Source: NRIC and Idaho National Laboratory (INL) study: Opportunities for the Development of Commercial Maritime Surface Vessel Nuclear Propulsion

A regulator in every port

Regulation must also be seen to be strict enough to protect from accidents, especially when considering port access.

Nuclear-powered naval vessels are not permitted to travel to every port due to tight restrictions on how closely a functioning nuclear reactor can be to civilian infrastructure.

“The way to get a nuclear submarine or an aircraft carrier, or even other nuclear powered warships, into any commercial port around the world is after lengthy negotiations between the port authorities and the Navy operating the warship,” says Chairman and CEO of Core Power Mikal Bøe.

At least, if there is an accident with a military ship in port, the military is not expected to just walk away or claim no responsibility and the associated government will be on the hook.

For a commercial vessel, the question of liability is more complicated.

“The reason we don't have (commercial) nuclear ships on the water today is because with current nuclear technology, they can't be insured and without insurance, port calls are off the table," says Bøe. 

"Since there will be no net-zero without nuclear, we need new nuclear technologies that are suited to a marine environment and that are commercially insurable. Then, and only then, can we make serious strides to decarbonize ocean transportation."  

Strong regulation would go a long way toward promoting an insurable nuclear-powered shipping sector while harmonizing a myriad of sovereign regulatory regimes for the global shipping industry is vital for public acceptance at each port the ship visits and key for insurance purposes.

Few in the industry are betting on short-term globally accepted, unified regulations governing nuclear power, and developers are pragmatic on how to approach this challenge.

At NuProShip 1, Emblemsvåg hopes the move away from traditional light water reactors will help the public understand that the technology is fundamentally different and, meanwhile, expects governments to be insurers of last resort for the first few commercial ships.

Cross-border, harmonized licensing would be a major development for nuclear in general, but nuclear shipping in particular, and work on that is ongoing via bodies such as the International Atomic Energy Agency (IAEA) and the World Nuclear Association.

NuProShip 1, meanwhile, is starting operations with an eye on a couple of fixed terminals, reducing the number of necessary licensing authorities to two.

“From a realistic point of view, we need to start with terminal-to-terminal ships first, and then terminal- or industrial port-to-industrial port, and then later on general port-to-general port,” says Emblemsvåg.

By Paul Day