Imagining a nuclear reactor humming beneath a container ship in the middle of the Pacific, surrounded by piled boxes of running shoes and smartphone parts, has a subtle surreal quality. It sounds like a plot point from a thriller about the Cold War. However, if you walk into the right conference room in Oslo or Seoul right now, engineers, insurers, and classification societies—all of whom deal with probability rather than fantasy—will be discussing that image with all seriousness.
It’s difficult to dispute the numbers that are driving this discussion. Approximately 350 million tonnes of fossil fuel are burned annually by the shipping sector, which contributes about 3% of the world’s carbon emissions. Shipping is the circulatory system of global trade; almost everything produced somewhere and consumed somewhere else travels by sea. This may not sound disastrous when compared to aviation or heavy industry. The cost of everything includes emissions, which are both enormous and invisible.
The International Maritime Organization set a net-zero goal for approximately 2050 in 2023. Although widely applauded, that ruling left shipowners facing an issue for which there was no clear solution. Short coastal routes can be powered by batteries. Although methanol and ammonia are promising alternative fuels, their supply chains are hardly operational at scale. Nuclear propulsion gradually moved from the periphery into the feasibility column as a larger solution was required.
The Norwegian classification society DNV, which is known for its methodical, conservative evaluations, recently released a white paper that delves deeply into the technical aspects of maritime nuclear propulsion. The change in language was apparent, but the tone wasn’t evangelical—it never is with DNV. According to the paper, nuclear propulsion is “now under active consideration as a real option for the commercial maritime fleet.” That phrase is significant for a company that spends the majority of its time managing risk.
Nuclear power itself has not changed. It’s the reactor. Fourth-generation SMRs, or small modular reactors, have passive safety features, are physically small, and may be produced in standard batches as opposed to custom construction projects. For shipping, where ships must be practically maintainable and economically replicable across dozens of ports in dozens of jurisdictions, this modularity is crucial.
DNV recently granted South Korean shipbuilder HD KSOE an Approval in Principle for a 15,000 TEU container ship based on SMR technology. That’s one of the biggest classes of container ships operating today. A supercritical CO2-based power system is incorporated into the design, which is said to increase thermal efficiency while lowering equipment footprint. Last year, Oslo hosted a HAZID workshop to formally map possible accident scenarios, such as collisions, groundings, and sinkings. The containment and shielding system was created especially to withstand all three. When it comes to public acceptance, it’s possible that the most important factor will be detail alone.
since it will turn into that conflict. Nuclear shipping regulations will be far more complicated than anything the maritime sector has ever faced. DNV is open about this. From fuel loading procedures to spent fuel storage and long-term waste disposal, the IMO and the International Atomic Energy Agency will have to coordinate standards that do not yet exist. The industry seems to recognize this and is starting to take action, but coordination at that level seldom proceeds smoothly or swiftly.
It’s difficult to ignore the concurrent conflict between caution and urgency as this develops. According to DNV’s own case studies, if complete decarbonization is accomplished by 2050, a reactor costing less than $18,000 per kilowatt might be commercially competitive. That threshold is not unachievable; rather, it is significant. The marine systems company ABB has been preparing for an anticipated market by developing nuclear-electric propulsion architecture for years.
It’s still genuinely unclear if that market will arrive on time. Technology is developing. They’re not the institutional frameworks. However, the fact that reactor designs are passing formal safety reviews is noteworthy in and of itself for a sector that has relied on diesel engines since the early 20th century.
