2025 was a challenging year for the maritime industry’s decarbonization efforts. Despite an acceleration in the industry’s engagement in low-carbon clean technologies, international shipping emissions largely returned to 2008 levels. However, the year also saw significant regulatory developments and technological advancements that could shape the future of maritime decarbonization.
Early in January, the introduction of FuelEU Maritime (FEUM) marked one of the most comprehensive pieces of regional emissions legislation to date. FEUM aims to incentivize the integration of low-carbon alternative fuels, setting a positive tone for the year. This was quickly followed by the unveiling of the International Maritime Organization’s (IMO) proposed Net Zero Framework, which sought to unify fragmented regional emissions regulations into a single global framework. However, the framework’s delay following the Marine Environment Protection Committee’s (MEPC) extraordinary meeting in October left the industry grappling with regulatory uncertainty and a patchwork of regional regulations.
Despite these challenges, the maritime industry remains steadfast in its commitment to achieving the IMO’s 2050 net-zero target. It is within this context that the potential of nuclear technologies has gained significant traction for marine deployment.
In a recent technical report titled “Maritime Nuclear Development,” Bureau Veritas Marine & Offshore (BV) details how technical viability and significant technological improvements in the new generation of reactors (Gen.IV) could lead to the first Small Modular Reactors (SMRs) being deployed in maritime applications from as early as the mid-2030s. These reactors, which include high-temperature gas reactors, molten-salt reactors, and liquid-metal reactors, are described as small (between 15 and 300 MWe per unit) and intended to be built in series in dedicated manufacturing plants. They are then transported (unfueled) to shipyards ready for integration into assets.
One of the most notable features of Advanced Modular Reactors (AMRs) is their inherent safety characteristics. These reactors use natural phenomena to protect the reactor’s core integrity, allowing the systems to shut down without the need for external power or human intervention, ensuring a “walk-away-safe” state during emergencies. This passive safety design addresses widespread market skepticism and public concerns about the risks of nuclear technology.
However, the regulatory landscape governing nuclear propulsion technology remains significantly fragmented. Nuclear regulation is at the national level/jurisdiction, while maritime regulation is at the international level. This fragmentation has led to a need to align various regulatory frameworks to allow for civil applications, resolving the issue of multiple conflicting jurisdictions that nuclear vessels will have to cross.
To secure the significant potential that modern nuclear propulsion technology represents, clear liability provisions must be established, supported by coherent and codified regulatory structures. The 1962 Brussels Conventions, which sought to establish a liability framework for nuclear-powered ships, never entered into force due to the lack of ratifying countries. Existing nuclear guides from the International Atomic Energy Agency (IAEA) do not provide for the transportation of nuclear reactors once they have been fueled, establishing a clear regulatory gap.
The IMO’s 1981 Nuclear Ship Code, the key instrument governing the deployment of nuclear civil propulsion, needs to be drastically updated to accommodate advances in modern nuclear propulsion technology. Greater collaboration and alignment between the IAEA and IMO to define a modern regulatory framework will accelerate the development of nuclear propulsion in commercial shipping, unlocking significant investment within the sector.
The IMO has implicitly acknowledged the need to address these regulatory inconsistencies and has directed its Sub-Committee on Ship Design and Construction (SDC) to prepare a roadmap for the revision of the Nuclear Ship Code to be presented for a vote at the Maritime Safety Committee 111. As regulatory clarity develops, industry bodies remain committed to supporting the safe development of nuclear propulsion technologies.
As a leading classification society, BV has taken a central role in this effort through participation in the International Association of Classification Societies (IACS) working group on nuclear propulsion, as well as in the different initiatives of marine nuclear deployment at the IAEA, and as a founding member of the Nuclear Energy Maritime Organization (NEMO). More recently, in November 2025, BV co-headed the signing with more than 30 European companies from the French and international nuclear and maritime sectors, of the Declaration for Accelerating Nuclear for Maritime Applications during the World Nuclear Exhibition in Paris. The signing represents a landmark initiative that unites international stakeholders across the nuclear, maritime, research, financial, and regulatory communities in a shared commitment to promote a European initiative to advance the safe and sustainable use of nuclear technologies for maritime decarbonization.
The challenges facing the development of viable commercial applications of nuclear propulsion technology are multifaceted and complex. However, positive market signals from both regulatory and industry bodies mark a tipping point in the technology’s progression.