Classification society DNV has published a white paper claiming that nuclear propulsion could become a viable long-term solution for maritime decarbonisation, despite no civilian commercial nuclear-powered vessel having been commissioned in more than four decades.

The report, titled "Maritime Nuclear Propulsion: Technologies, Commercial Viability, and Regulatory Challenges for Nuclear-Powered Vessels," examines how maritime nuclear technologies differ from land-based reactors and addresses technological, regulatory, and commercial factors that would need to be resolved for nuclear propulsion to play a role in shipping's energy transition.

According to DNV, shifting environmental requirements are reigniting interest in nuclear propulsion as the industry seeks alternatives to fossil fuels. The last civilian commercial nuclear-powered vessel to be commissioned was the Russian cargo ship Sevmorput in 1988, which remains in operation today.

The paper addresses elements of the future maritime fuel cycle, including fuel management, waste handling, vessel construction and operation, and oversight of nuclear supply chains. It presents reactor technologies most likely to be adopted by shipowners and identifies advances in automation, digitalization, and modular design as enablers of safety, security, and non-proliferation.

Knut Ørbeck-Nilssen, maritime CEO at DNV, said: "Nuclear energy has the potential to play a role in the maritime energy transition. However, much work still needs to be done to overcome technical, regulatory, and societal challenges, including public perception. This will require coordinated global action, technological innovation, and closely aligned regulatory frameworks."

The white paper stresses the need for a predictable and harmonized regulatory framework at both national and international levels. According to DNV, regulators including the International Maritime Organization and International Atomic Energy Agency, along with flag states, national authorities, and classification societies, must play a coordinated role. The report outlines likely regulatory roadmaps for all relevant actors.

DNV says mass production, standardization, and modularization can strengthen the business case for nuclear-powered ships. The report includes a case study examining what cost levels marine nuclear reactors would need to reach for nuclear propulsion to become viable for the merchant fleet.

Ole Christen Reistad, senior principal researcher at DNV and lead author of the paper, commented: "For nuclear propulsion to become commercially viable in shipping, the business case must account for the full lifecycle costs, including fuel supply, reactor maintenance, and waste management. Modular and standardized reactor designs can significantly reduce capital and operational expenditures, while robust regulatory frameworks and predictable supply chains are essential for investor confidence and long-term competitiveness."

Previous attempts to develop civilian nuclear-powered merchant vessels have faced economic and operational challenges. The US-built NS Savannah operated from 1962 to 1972 but proved too expensive to run commercially. Germany's Otto Hahn cargo ship and Japan's Mutsu research vessel also failed to achieve commercial viability.