Chinese scientists have completed a major breakthrough in clean energy by reloading fresh fuel into a working thorium molten salt reactor. They did this while the reactor continued running, marking a significant step forward in the global push to use thorium as a safer and more abundant alternative to uranium in nuclear power. The milestone was revealed at a closed-door meeting on April 8 at the Chinese Academy of Sciences (CAS), where project chief scientist Xu Hongjie shared the news with colleagues.
Thorium reactor begins real-world operation in China
According to Guangming Daily, the experimental unit is located in the Gobi Desert and generates 2 megawatts of thermal power. It uses molten salt to carry the fuel and manage heat, while thorium serves as the radioactive fuel source. Experts have long viewed thorium reactors as the next leap in energy innovation. Some scientists estimate that a single thorium-rich mine in Inner Mongolia could theoretically supply China’s energy needs for tens of thousands of years with far less radioactive waste than current uranium-based reactors. Xu declared that China had moved into the global lead. “We now lead the global frontier,” he said at the meeting. Comparing the international race to a classic fable, he added, “Rabbits sometimes make mistakes or grow lazy. That’s when the tortoise seizes its chance.”
Why thorium could change the future of nuclear energy
Thorium offers several advantages over uranium as a nuclear fuel. It is far more abundant in the Earth’s crust and produces less long-lived radioactive waste. Its byproducts are also less suitable for weaponization, which reduces security risks. When paired with molten salt technology, the reactor design operates at atmospheric pressure and naturally limits overheating, improving overall safety. These features make thorium reactors appealing in a world pushing for clean and secure energy sources.
China advances
In the 1960s, American researchers built and tested early molten salt reactors, but the United States eventually shelved the program in favor of uranium-based technology. “The US left its research publicly available, waiting for the right successor,” Xu said. “We were that successor.” Xu and his team at the CAS Shanghai Institute of Applied Physics studied declassified American documents, recreated the old experiments, and then developed the technology further. “We mastered every technique in the literature – then pushed further,” he said. The team’s efforts ramped up quickly. Construction on the current reactor began in 2018, and the team grew from a few dozen researchers to more than 400. Many skipped holidays and stayed on-site for most of the year. The reactor reached criticality in October 2023, achieved full-power operation by June 2024, and successfully completed in-operation thorium reloading just four months later.
Bigger thorium reactors already in progress
Xu said they chose the harder but more meaningful road by focusing on building a real-world solution rather than chasing only academic results. “We chose the hardest path, but the right one,” he said. He also pointed out the symbolic timing, noting that “57 years ago to the day – June 17 – China detonated its first hydrogen bomb.” Now, China is aiming for a similar disruptive effect in the global energy market. The country is already building a much larger thorium molten salt reactor that is scheduled to reach criticality by 2030 and generate 10 megawatts of electricity. Meanwhile, China’s shipbuilding industry has also unveiled blueprints for thorium-powered container ships that could enable zero-emission sea transport.
