China’s ambitious plan to dramatically pull back from fossil fuels is perhaps most evident in the explosive growth of its nuclear energy program. The latest news suggests China may be tantalizingly close to bringing self-cooling reactors to practical use—a development with profound safety implications.
In a statement earlier this week, the China Institute of Atomic Energy (CIAE) announced that it had recently concluded tests for a residual heat removal system for integral fast reactors (IFRs). The statement did not specify a date but noted that the breakthrough would effectively make China’s radioactive waste-recycling power plants meltdown-proof.
Specifically, the new technique prevents the reactor core from overheating through a mechanism that naturally cycles the coolant to dissipate unwanted, leftover heat.
“Removing residual heat from the reactor core is inherently critical to the safety of the reactor,” explained the CIAE. “This is the first proof-of-principle test in China for a new passive residual heat removal technology for [integral] fast reactors.”
The merits of a self-cooling fast reactor
To be clear, this is a separate result from a 2024 experiment that successfully tested a self-cooling, high-temperature reactor using a pebble-bed module. The new result is the proof-of-principle test for a self-cooling mechanism implemented into an IFR, which uses high-energy “fast” neutrons to cause and maintain fission chain reactions.
Unlike conventional reactors cooled by water, IFR coolants are often liquid metals, such as sodium or lead. Overall, this scheme enables IFRs to extract 100 times more energy than conventional reactors with a higher fuel efficiency. IFRs often operate on a closed-loop fuel cycle, meaning spent fuel can be recycled, which the Department of Energy explains could reduce nuclear waste by up to 90%.
The first concept and deployment of an IFR began at Argonne National Laboratory in the U.S., although the project was later canceled. As of now, the United States does not have a commercially active IFR.
China, on the other hand, expressed strong interest in expanding the use of IFRs in its nuclear energy program during a presentation to the International Atomic Energy Agency.
Hot topic, cool implications
For the new result, researchers first simulated how their mechanism would unfold inside an actual reactor. Based on those simulations, they developed a test facility for “understanding the operating principles of the novel passive residual heat removal system for integral fast reactors,” according to the CIAE.
This technology has already been incorporated into the design of the CFR-1000, China’s next-generation gigawatt-level fast reactor, the agency said, adding, “Effectively implementing and verifying natural circulation in fast reactors is currently a hot topic and a challenge internationally.”