Classification society DNV on Wednesday (21 January) outlined opportunities, challenges, and pathways for integrating nuclear technology into commercial shipping in a whitepaper:
Nuclear propulsion, dormant in commercial shipping for decades, is gaining renewed interest as the industry seeks scalable, zero-emission solutions. Apart from being an energy source which produces no emissions, nuclear propulsion offers other advantages, such as stable, predictable energy costs, enhanced operational flexibility (including the economic feasibility of higher speeds), and reduced reliance on traditional bunkering infrastructure.
DNV’s white paper describes the state of play of nuclear maritime propulsion today, and emphasizes the need for technological innovation, regulatory clarity, and economic pragmatism for the industry to become viable in the future.
A short history of maritime nuclear propulsion
Nuclear propulsion in shipping first came to prominence during the so-called nuclear age of the 1950s and 1960s. With the land-based nuclear industry growing strongly, several military vessels were commissioned, mainly in the US and Russia. This was accompanied by some exploratory civilian projects, such as the Savannah, which entered into service in the US in 1962, and the German Otto Hahn and Japanese Mutsu, which followed soon after. All of these operated using pressurized water reactors (PWRs), which required extensive monitoring and active safety systems to manage transients.
However, most of these projects were not commercially viable and, apart from continued exploratory tests in Russia, no civilian commercial maritime nuclear projects have been commissioned in over 40 years.
In recent years, the growing need to decarbonize shipping, combined with the wide range of difficulties associated with this – such as limited supply of low-greenhouse gas fuels – has led to many in the industry re-evaluating nuclear propulsion as a potential problem solver.
Building nuclear reactors for maritime use
While a future civilian maritime nuclear industry can draw on lessons learned from the more established land-based industry, shipping creates its own demands and the white paper outlines reactor concepts being developed specifically for maritime use.
“All reactors should take into account factors unique to shipping, such as mobility, exposure to harsh sea conditions, and operational profile, while also bearing in mind key considerations like cost, space, reliability, power availability and, most importantly, safety,” says Ole Christen Reistad, Senior Principal Researcher and lead author of the white paper.
“Smaller, standardized reactors with passive safety and minimal crew needs may benefit merchant shipping, while low-pressure systems and Generation IV or heat-pipe reactors could provide safer, simpler alternatives to PWRs.”
As explained in the white paper, marine reactors must be compact and designed for infrequent refuelling, ideally aligned with other required maintenance activities such as dry-docking to minimize impacts on ship availability. Issues around surveyance at sea and safety can be mitigated through remote monitoring and advanced communication capabilities. Several projects are already underway in different countries, with differing approaches to fuel, coolant and safety.
The maritime nuclear fuel cycle in perspective
Going beyond reactors, DNV’s white paper also identifies the need for a dedicated, cost-effective maritime fuel cycle. This should encompass all stages, from ‘front end’ to ‘back end’, including key aspects such as fuel qualification and fabrication, spent fuel storage, and disposition.
“Any future commercial maritime nuclear fuel industry should be centred around a specific nuclear fuel cycle for maritime use, with recognised roles and responsibilities across the supply chain, from fuel production and reactor integration to loading, exchange, and disposal,” says Reistad.
Storage and disposal of spent nuclear fuel will be fundamental to the functionality and credibility of the supply chain. This will also be crucial for advancing public acceptance of the maritime fuel cycle.
Note: The full whitepaper by DNV can be viewed here.
Photo credit: Venti Views on Unsplash
Published: 23 January, 2026
