In response to increasing pressures for eco-friendly and emission-free maritime shipping, leaders in the shipping industry are taking action to transition from polluting ships to smart, green vessels. With around 90% of global trade transported by sea, shipping accounts for nearly 3% of worldwide emissions. The International Maritime Organization (IMO) has established a new greenhouse gas strategy aiming for zero emissions by 2050, which includes a target for sustainable fuels to represent 10% of energy usage in maritime transport by 2030.
This has spurred both nations and major corporations to develop ships that reduce carbon emissions. For instance, large retailers such as Amazon, IKEA, and Lidl plan to use only carbon-free fuel ships by 2040. This shift opens new horizons for innovation within shipbuilding and necessitates close collaboration among various stakeholders, from manufacturers to operators and regulatory institutions, to make emission-free shipping a reality.
Towards Nuclear-Powered Commercial Vessels
Building on the aforementioned goals and striving to reduce the shipping industry’s carbon footprint, nuclear energy emerges as a promising and reliable solution for significantly lowering emissions from maritime shipping. This is due to its ability to enable ships to undertake long voyages without the need for frequent refueling. This approach paves the way for cleaner shipping using more sustainable materials, alternative fuels, green propulsion solutions, and increased automation, alongside the use of autonomous and remotely operated vessels. This fundamentally rethinks how commercial ships are designed, built, operated, and maintained, which entails building and successfully integrating a wide array of complex technologies.
Unlike fossil fuel-powered ships, nuclear-powered vessels emit significantly lower amounts of greenhouse gases and air pollutants, making them a more sustainable option. Furthermore, utilizing nuclear propulsion can also avoid frequent oil spill incidents, which occur regularly. Despite technical challenges in scaling up the production of green ammonia, methanol, and hydrogen, the shipping sector is increasingly interested in nuclear power, especially as nuclear fuel is well-suited for vessels that remain at sea for extended periods; it reduces the need for refueling and results in zero carbon emissions.
Nuclear-powered ships operate by having a nuclear reactor on board that heats water to generate electricity, which in turn powers generators and turbines to propel the ship. The first-ever nuclear-powered ship was the USS Nautilus submarine, launched in 1954, followed by the USS Enterprise aircraft carrier in 1961. Since then, nuclear energy has typically been used in military vessels such as submarines and aircraft carriers. However, under the “Atoms for Peace” program, the first commercial nuclear-powered ship, the NS Savannah, was launched in the early 1950s, although it was not developed for long-distance shipping. Only a handful of countries, most notably the U.S., Russia, Germany, and Japan, have utilized nuclear power in commercial vessels, and on a very limited scale since then.
In pursuit of establishing green commercial ships according to the IMO’s vision, some nations and public and private companies are focusing on supporting modern technologies such as high-fidelity modeling and advanced construction techniques to improve the design of small reactors for powering cargo ships. For example, the British company Core Power is independently working to develop an advanced molten salt-cooled reactor that uses liquid fuel instead of solid fuel, addressing common weaknesses in conventional nuclear reactors. Meanwhile, in Italy, the RINA group, a leading classification society, is exploring ways to utilize nuclear fuel in commercial vessels, stating that this will take between seven to ten years to become feasible for production and application.
South Korean and Chinese Initiatives
Within the global efforts to trial and develop nuclear-powered container ships for a more sustainable maritime industries, South Korea and China stand out as key players in Asia attempting to contribute to these efforts, which are replete with scientific, engineering, and technological challenges:
- South Korea: Recognized as a leader in shipbuilding, South Korea boasts extensive expertise in maritime engineering and nuclear technology, aiming to leverage this knowledge to develop nuclear-powered container ships as a core component of its strategy for achieving carbon neutrality in the shipping sector. In January 2023, Samsung Heavy Industries announced that it had completed the conceptual design for the CMSR energy ship, which operates through a floating nuclear power station based on molten salt reactors.
In February 2023, the Korea Institute of Ship and Ocean Engineering signed a memorandum of understanding with eight other South Korean organizations to collaborate on developing a molten salt reactor suitable for marine use, agreeing to cooperate in developing and testing small nuclear reactors for generating electricity for marine applications and training experts to operate nuclear-powered vessels.
Furthermore, in February 2024, a major South Korean shipbuilding company signed a cooperation agreement with prominent nuclear energy firms Core Power and TerraPower for a project to construct the first fast molten salt reactor using chloride, with the goal of commercializing nuclear technology and utilizing it in commercial vessels by 2035.
Additionally, another consortium of organizations signed a memorandum of understanding in early 2024 to develop nuclear-powered container ships using standard small nuclear reactors. While specific details of this latter project have not been disclosed, these alliances intend to make nuclear energy commercially viable, focusing on using molten salt-cooled reactors that dissolve nuclear fuel in molten fluoride salts. The concept of these reactors is not new, as similar reactors operated briefly in the 1960s, but numerous technical challenges and financial costs have prevented their widespread deployment.
Through these multiple initiatives, the American Bureau of Shipping has collaborated with the Korea Institute of Ship and Ocean Engineering to develop small nuclear-powered commercial vessels and floating nuclear power generation platforms. The institute will handle foundational technical developments, including conceptual designs, nuclear propulsion systems, integrated safety analysis frameworks for nuclear ships, and the design of floating platforms for small nuclear power generation, alongside a business model that can provide stable energy for island areas.
- China: As one of the world’s leading shipbuilding nations, China is making significant strides in developing nuclear container ships, aiming to produce small, efficient nuclear reactors to power commercial vessels. On December 7, 2023, China unveiled the design for the world’s largest nuclear-powered container ship, indicating a major contribution to cost reduction and sustainability through nuclear fuel while maintaining a low environmental footprint. This was announced during the “China Maritime Transport Technology and Technology Exhibition” held in Shanghai, where Jiangnan Shipyard revealed a design for a ship that will accommodate 34,000 TEU (twenty-foot equivalent units).
Chinese reports indicate that this vessel will feature a range of advantages that make it an innovative and sustainable choice in green maritime shipping, notably a safe energy system and high efficiency. This system is designed based on the “double containment principle,” positioning the nuclear power unit at the ship’s core to ensure continuous energy supply. The ship will also be equipped with a hybrid and comprehensive propulsion system entirely reliant on an electrical system powered by dual engines and multiple propellers, with a power generation system based on supercritical CO2 generators, alongside a compact standardized nuclear design. Additionally, this ship is anticipated to be economically efficient; its battery will only need to be replaced every 15 to 20 years, reducing long-term operational costs.
The Chinese shipping sector has made a significant leap by designing a new ship powered by “molten salt” reactors, which received preliminary approval from the Norwegian Maritime Classification Society, marking an achievement toward developing ships that are free of carbon emissions. This comes alongside the commissioning of China’s first fourth-generation nuclear plant in Shidaowan, which utilizes high-temperature gas-cooled reactor technology, opening new avenues for safe and efficient nuclear power generation.
On another front, China announced in November 2024 the construction of a prototype ground-based nuclear reactor for a large warship, a clear indication of its progress toward producing its first nuclear aircraft carrier. According to recent analyses of satellite imagery and Chinese government documents published by the Associated Press, the Chinese navy is currently the largest in the world by number, and adding nuclear-powered aircraft carriers to its fleet will enhance its ambition to become a naval power capable of efficient operations in distant seas amid competition with the United States.
Finally, the efforts and experiments from China, South Korea, and other nations indicate that nuclear energy could play a crucial role in shaping the future of maritime shipping. With continuous advancements in small nuclear reactor technology, nuclear vessels may become a reality in the near future. However, achieving this goal requires substantial investments in research and development and the creation of innovative solutions to the technical challenges facing this technology and its applications within commercial ships. Additionally, should these challenges be overcome and such ships are constructed, a new array of regulatory and legal challenges will emerge regarding their passage and docking in ports worldwide, necessitating a comprehensive agreement to ensure the protection, regulation, and commercial insurance of nuclear vessels.
