Nuclear power has been used at sea since the US Navy launched the Nautilus in 1955 (pictured above*). In the meantime, there have been many thousands of safe reactor operating years achieved in the maritime environment. Today, there are approximately 100 reactors in maritime use. Russia has operated nuclear-powered icebreakers since 1957 and has a floating nuclear power plant operating, China is also expected to build 20 floating nuclear power plants.

It’s quite clear that nuclear power in the maritime environment is a proven technology, it is also completely zero-emission. So, is power from the atom an option to help the industry meet the IMO GHG 2050 requirements? Public perception is an important factor to consider when looking at nuclear power, some say, ‘it’s too expensive’ or ‘it’s not safe’ and ‘we do not understand it’. LR’s Global Head of Technology, Risk Management, Vince Jenkins takes a closer look at these challenges and determines whether they are true or false.


The power source is often labelled ‘expensive’ – this is true as nuclear front-loads the CAPEX costs. The OPEX costs, however, are relatively low since the fuel is a small part of the cost. A nuclear build typically looks at total life costs, which is different to how ships are currently built and operated, which is CAPEX costs and then OPEX. Decommissioning and storage of used fuel is a cost which is included in nuclear builds, this is a contrast to how the waste from fossil fuel is treated, which is emitted into the atmosphere and has contributed to shipping’s CO2 emissions.

With all future fuels, the industry needs to consider the total externalities of their use which will have to be controlled and costed. A matter which is currently being debated by the IMO – specifically the market-based measures, a pricing mechanism for emissions.

Volume production, by which we mean the total amount a company can produce over time, is not something that the nuclear industry has focused on in the past, it tends to be one-off plants. Now, there are companies designing small modular reactors (SMRs). Unlike the GW power station plants, SMRs are in the 10’s – 100’s MW size, which focus on volume production and significantly reduced costs. There are also new reactor designs, such as molten salt reactors (MSRs), being developed which target the maritime sector, with some claiming that costs are competitive with the expected zero-emission fuels, a compelling argument.

Nuclear locks in future fuel costs so fuel price variability is removed, this is because reactors require at most refuelling every 3-5 years. MRSs, currently being developed by TerraPower and CorePower, can fuel a ship for up to 25-30 years, the lifetime of most ships. This means the global production and supply chain is massively reduced when compared to more conventional liquid fuels. For ammonia and hydrogen, the logistics chain has yet to be established.

Safety implications

Surprising to some, the nuclear industry has an enviable safety record. Our World in Data, part of Oxford University, produced a graphic in February about the ‘Safest and cleanest source of energy’, which examined coal, oil, natural gas, biomass, hydropower, nuclear, wind and solar. Just behind wind, hydropower and solar, nuclear was the safest in terms of lowest death rates and emitted the lowest amount of GHG emissions compared to all other fuel types. Although, let’s be clear, the inherent hazards of any of the new powering technologies, whether that’s ammonia, hydrogen or nuclear, will have to meet the maritime safety standards established.

There are existing regulations in place for nuclear power such as SOLAS Chapter VIII, written in the 1970s, which refers to nuclear propulsion. This was developed around the safety of pressurised water reactors (PWRs) and focused on safety standards at that time. With more than just PWR technology available today and safety and security challenges evolving with each piece of technology, the statutory regulation would require an extensive review and upgrade. Furthermore, it’s likely that UNCLOS, the piece of UN legislation which allows ships to move from one country to another unimpeded, irrespective of propulsion type or cargo, will need to be adapted to allow free global movement of nuclear powered vessels. Point to point operation, however, would just require the agreement of the countries involved. LR produced a high level framework of rules for nuclear propulsion in 2010, with the key focus of safely integrating a licence reactor into a ship, and can be considered a ‘strawman’ for the industry when considering nuclear power.

Lack of understanding

It’s true that the physics of liberating energy from the atom are different from burning a liquid fuel in an internal combustion engine or using batteries, for instance. Nuclear technology also introduces significant changes in terms of how the industry would operate. For example, there is little, or no bunkering required, depending on the reactor, which raises questions around how the fuel paid is for, particularly as charterers normally pay for it. There are many other changes which would need to be addressed.

Monumental structural changes like these are always challenging. The maritime industry has been here before however, when we moved from sail to steam and then to the internal combustion engine, or the move from break bulk cargo to containers. The next structural change of zero emission ships will be just as challenging.

Of course, there’s no ‘silver bullet’ or single solution to shipping’s zero carbon transition and it’s likely that a group of fuels will be selected, particularly as each owner and ship type varies in terms of operational needs. Each fuel option brings its own inherent hazards which must be managed, which will incur substantial investment. The significant cost of establishing a global supply chain and port infrastructure for the bunkering of liquid fuels should not be underestimated.