Nuclear Reactors Are a Clean Energy Solution for Civil Maritime

Although nuclear power has been used successfully to power US military vessels since the 1950s, use for civilian maritime purposes has never evolved beyond a few experimental designs. High initial capital costs and concerns about safety kept nuclear power for the civilian maritime fleet from reaching criticality.

However, innovations in nuclear technology, combined with a push to decarbonize the civilian maritime industry, now offer the opportunity to revitalize the concept at commercially viable costs.

The US Navy has employed dozens of nuclear-powered warships without any significant reactor-related safety events. The US, however, has built only a single nuclear-powered merchant ship—the proof-of-concept N.S. Savannah. A hybrid cargo and passenger vessel, the Savannah operated successfully from 1959 through 1972 but its limited cargo and passenger capacity made continued operation uneconomical.

The intent behind the Savannah was merely to prove the concept. And it did. Several other countries successfully operated experimental nuclear-powered civilian vessels but, as was the case in the US, widespread adoption never occurred.

Advantages of Nuclear-Powered Vessels

Nuclear propulsion has always produced several key advantages over conventional fuel sources.

First, nuclear-powered vessels can go years without refueling. Even though conventional vessels can typically refuel concurrently with cargo operations, owners of nuclear vessels could worry less about fuel price volatility since uranium pricing is not as volatile as oil. Relatedly, the large up-front capital cost of a nuclear reactor may be outweighed by the steady cost of fuel consumption, which for a large container ship can exceed $3 million a month.

Second, the energy density of nuclear fuel eliminates the need to store millions of gallons of fuel oil. This benefit eliminates the traditional trade-off between fuel storage and cargo space. Nuclear vessels can repurpose the space occupied by fuel tanks for cargo.

Even taking the necessary shielding into account, compared to a conventionally powered large container vessel, a similarly sized nuclear-powered vessel could hold more standard shipping containers and operate at higher speeds.

Relatedly, on nuclear-powered ships there would be no fuel tanks to rupture in the event of a maritime casualty, preventing the discharge of thousands of barrels of fuel oil into sensitive littoral environments and the associated costs of remediation.

A July 2023 study by the American Bureau of Shipping confirmed these first two points. Based on one model, the study found that using two 30-MW fast reactors on a large container ship would increase cargo capacity and operating speed.

In another configuration, employing four 5-MW heat-pipe microreactors on a large tanker would decrease cargo capacity but increase operational speed. And, in both examples, the fuel could last for 25 years—the typical operational life of a commercial vessel.

Third, the conventional fuel is bunker oil, and it emits combustion byproducts such as carbon dioxide and particulate matter. As environmental regulations regarding emissions tighten globally, nuclear power offers a reliable source of clean, carbon-free energy.

Advancements in Reactor Technology

Recent advancements in nuclear reactor technology enhance the competitiveness of nuclear-powered vessels. The advent of micro- and small-modular reactors offers a standardized design that can achieve the economy of scale to make SMRs cost-effective. Although these designs were intended for onshore power generation, their size and standardization make them suited for use on commercial vessels.

The high number of large commercial vessels creates the potential for mass deployment, creating benefits from economies of scale, standardized operator training, and stable supply chains.

Several SMR designs in the licensing stage before regulatory authorities in Canada, Japan, the UK, and the US produce sufficient electricity to power the largest container ships, and several smaller SMR designs would suffice for smaller vessels.

New advanced reactor designs cooled by molten salts or liquid metal may offer a reactor type that could be well suited for maritime transportation applications. Because these reactors operate at ambient pressure and solidify if the reactor stops, there is little risk of environmental contamination in the event of a reactor emergency.

Competitive power markets and behind-the-meter generation programs, which exist in much of the US, offer a supplemental source of revenue for nuclear-powered vessels. While many ships would tie into shore power to save fuel when docked, the nuclear reactor can continue to operate.

These vessels would not only avoid having to consume electricity in port, but they could look to export power to the grid or facilitate net energy billing for energy-intensive port facilities.

The next generation of advanced nuclear reactors is already being developed for onshore electricity production. These reactors can be readily adapted to civilian maritime uses, offering a safe, reliable, clean, and cost-effective source of energy.

This article does not necessarily reflect the opinion of Bloomberg Industry Group, Inc., the publisher of Bloomberg Law and Bloomberg Tax, or its owners.

Author Information

Patrick R. Pennella is an associate at Morgan, Lewis & Bockius.

Alex Polonsky is a partner at Morgan, Lewis & Bockius and a member of the Civil Nuclear Trade Advisory Committee.

Jane Accomando is a partner at Morgan, Lewis & Bockius and a co-leader of the firm’s global energy industry team.

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