Maritime Nuclear Power: A Technological Leap Toward “Zero Emissions”?

By Colomban Monnier - President of the Governing Board of the ENSM Foundation

Faced with the physical and economic limitations of e-fuels, a disruptive option is gaining ground in expert discussions: fourth-generation civilian onboard nuclear power. This is not an easy solution, but a high-level engineering challenge. For young engineers seeking to work at the cutting edge of innovation, it is likely one of the most promising sectors of the next twenty years, where many solutions remain to be invented.

The equation is simple yet uncompromising: large transoceanic vessels require an energy density that batteries cannot provide and that e-fuels may struggle to supply in sufficient volumes. Nuclear power appears to offer virtually unlimited autonomy and zero greenhouse gas emissions during operation. However, the goal is not to replicate the military nuclear propulsion systems of the 1970s.

SMRs and MSRs: The Revolution of Passive Safety

The major innovation lies in Small Modular Reactors (SMRs) and Molten Salt Reactors (MSRs). These technologies aim for “passive safety”: in the event of a malfunction, gravity and natural convection alone are sufficient to shut down and cool the core, without human intervention or external electricity. This represents a complete paradigm shift, making civilian applications conceivable, particularly for mobile and lightweight installations such as ships.

For engineers in nuclear engineering, thermodynamics, and materials science, the challenges are immense. These technologies must be adapted to the maritime environment: how does a molten salt reactor behave in heavy seas? How can systems be designed to withstand marine corrosion over a 30-year vessel lifespan? How can plug-and-play modules be integrated into the architecture of a giant container ship?

A New Model: The “Nuclear Battery”

New economic models must also be developed, in which the ship’s hull is purchased and its propulsion system leased. The concept no longer involves refueling uranium onboard. Instead, it envisions a sealed nuclear battery, loaded for 30 years, installed during construction and removed at end of life for dismantling in specialized facilities, or potentially transferred to another vessel as needed.

This opens up fascinating career prospects for deck and engineering officers. The role would not be to become nuclear physicists, but to supervise highly advanced energy systems. Expertise in managing onboard nuclear energy systems could become a strong asset in the maritime job market, offering unprecedented levels of responsibility and compensation.

Building the Framework of Tomorrow

Of course, regulatory and societal barriers remain significant. Port acceptance and insurance issues are central concerns. Yet this is precisely where opportunities arise for young graduates in maritime law, public affairs, and risk management. An entirely new international framework must be created to allow such vessels to operate. Securing raw material supply chains could also reshape diplomatic and geopolitical balances.

From a sustainability perspective, while nuclear propulsion could theoretically eliminate most of the 3% of global emissions attributable to maritime transport, waste management, though reduced with molten salt reactor technologies, remains a major issue. The environmental impact of developing the supply chain and its infrastructure, which is highly concrete-intensive, must also be considered. Furthermore, the rebound effect of maritime decarbonization could potentially drive a renewed surge in global relocation of industrial production.

Maritime nuclear power is not a utopia; it is an industrial roadmap emerging for the 2035–2050 horizon. For those training today, it represents the opportunity to take part in the greatest propulsion revolution since the transition from sail to steam. It is also a field that raises profound societal and environmental questions.

1. Large vessels are equipped with batteries for maneuvering operations, but not for open-sea navigation.

2. See the report Navigating Nuclear Energy in Maritime by Lloyd’s Register.

3. In English-language literature: Small Modular Reactors (SMR).

4. In English-language literature: Molten Salt Reactors (MSR).

5. According to the International Energy Agency, the cement production sector accounts for 7 - 8% of global carbon dioxide emissions.