China’s Bold Leap Toward Nuclear-Powered Shipping: Inside the Thorium Revolution at Sea

China is developing a revolutionary cargo ship powered by a thorium molten salt reactor, offering safer, more efficient, and eco‑friendly nuclear propulsion. The 200‑megawatt system drives a supercritical CO₂ generator, supplying 50 MW of power for long voyages without refueling. With inherent safety, modular design, and up to 50% efficiency, the project could transform global shipping—though high costs mean government support may be essential for widespread adoption.

China has unveiled a major stride in maritime technology with the development of a next-generation container ship powered by a thorium molten salt reactor (TMSR)—a breakthrough that could redefine global commercial shipping. The vessel, capable of carrying 14,000 standard containers, will run on a 200-megawatt thermal nuclear system, rivaling the power capacities of the U.S. Navy’s advanced Seawolf-class submarines.

What makes this project particularly trailblazing is its reliance on thorium, a safer and more abundant alternative to uranium. Unlike conventional reactors that operate under high pressure and require vast cooling systems, the molten salt reactor uses thorium fuel that functions safely at atmospheric pressure without the need for water cooling. This design not only reduces size and noise but significantly boosts safety, addressing long-standing concerns about nuclear propulsion at sea.

A New Era in Maritime Engineering

According to Hu Keyi, a senior engineer at Jiangnan Shipbuilding Group, who disclosed the technical details in Ship & Boat on October 15, the ship’s thorium reactor does not directly power its engines. Instead, it supplies energy to a supercritical carbon dioxide (sCO₂) generator operating on the Brayton cycle—a high-efficiency thermal process converting heat into electricity more effectively than traditional steam turbines.

Through this closed-loop system, heated CO₂ expands through turbines, generating 50 megawatts of electrical output, enough to sustain long voyages across oceans without refueling. For redundancy, the design includes a 10-megawatt diesel generator that serves as an auxiliary power source in case of emergencies.

Built for Safety and Longevity

Hu emphasized that the reactor’s architecture inherently minimizes the risk of a meltdown or radiation escape. Operating at about 700°C (1,292°F) and at normal atmospheric conditions, the thorium-fueled molten salt setup eliminates the risk of explosive pressure buildup. The reactor also features two passive cooling systems—a natural circulation loop and an emergency drainage system that can funnel molten salt into secure containment tanks for cooling and solidification.

If all cooling systems fail, the reactor’s fuel would automatically drain into a shielded chamber, hardening into stable material and trapping radiation. Furthermore, the reactor’s 10-year modular design allows for straightforward replacement rather than refueling, significantly reducing operational hazards and maintenance downtime.

These features make the thorium system not only more compact but also far more efficient—boasting a thermal-to-electric efficiency of up to 50 percent, compared to roughly 33 percent in conventional uranium-based reactors.

Expanding the Nuclear Fleet

China’s nuclear ambitions at sea extend beyond the TMSR cargo ship. Hu revealed concurrent projects that include a nuclear-powered Suezmax oil tanker using lead-bismuth-cooled fast reactors and a floating power platform equipped with high-temperature gas-cooled reactors. While these designs deliver lower overall power, they represent strategic diversification in maritime nuclear technology.

The Thorium Advantage—and Its Challenges

Thorium’s appeal lies in its safety, abundance, and proliferation resistance. China’s domestic reserves, particularly in Inner Mongolia, contain vast quantities—enough to sustain the nation’s energy needs for centuries. Though the U.S. experimented with thorium reactors at Oak Ridge National Laboratory in the 1960s, the project was shelved due to material corrosion challenges.

China has since taken the lead, achieving a major milestone in 2025 with the first long-term operating thorium molten salt reactor in the Gobi Desert. A larger demonstration reactor is already under construction, signaling Beijing’s determination to translate experimental success into commercial applications.

Despite its promise, scaling nuclear shipping remains an economic challenge. High upfront construction costs, specialized training requirements, limited insurance coverage, and costly safety infrastructure could hinder commercial adoption. “The financial burden is too heavy for private companies alone,” Hu noted, calling for state-backed initiatives or guarantees to encourage investment in nuclear maritime technology.

The Future of Ocean Transport

If successful, China’s thorium-powered cargo ship could mark a transformative moment in global shipping—ushering in cleaner, safer, and virtually limitless marine propulsion. However, with financial and regulatory hurdles yet to be resolved, the realization of nuclear-powered freight fleets remains a journey still underway.

As the world looks toward decarbonizing transport and securing energy independence, China’s bold experiment may chart the course for a new nuclear age on the high seas.