Almost unlimited clean energy has been brought a step closer with the setting of a new world record for the sustained running of a nuclear fusion reactor.
China's "artificial sun"—formally known as the Experimental Advanced Superconducting Tokamak (EAST), and based in Hefei—maintained steady-state, high-confinement plasma operation for 17 minutes and 46 seconds. That's nearly triple the previous world record of 6 minutes and 43 seconds, which was also set by EAST, back in 2023.
Fusion reactors—which replicate the energy-producing processes that power the stars themselves—have the potential to revolutionize the energy sector.
"We hope to expand international collaboration via EAST and bring fusion energy into practical use for humanity," Professor Yuntao Song, director of the Chinese Academy of Science's Institute of Plasma Physics, said in a statement.
Unlike traditional fission-based nuclear reactors, which release energy through the splitting of large atoms, fusion reactors smash light atoms together to make heavier ones at temperatures exceeding 180 million degrees Fahrenheit.
This process releases a staggering amount of energy—many times more than achieved during nuclear fission—but at the same time produces no harmful byproducts.
EAST belongs to a type of fusion reactor known as a "tokamak." These are doughnut-shaped machines in which hydrogen fuel is transformed under intense pressures and temperatures into plasma—a hot, electrically charged cloud—and contained in a ring-shape, circling around inside the reactor, by powerful magnets.
It is within this plasma that atomic nuclei are forced to combine; with the heat energy released in the process harnessed by the walls of the tokamak.
Before nuclear fusion can become a commercial reality, however, a number of challenges must be overcome in experimental reactors like EAST.
"A fusion device must achieve stable operation at high efficiency for thousands of seconds to enable the self-sustaining circulation of plasma," said Song.
This, he explained, "is essential for the continuous power generation of future fusion plants."
EAST—which began experimental operations in 2006—has received a number of upgrades since its previous record-breaking run in 2023, Xianzu Gong, head of EAST's Physics and Experimental Operations division, explained in a statement.
For example, refinements to the reactor's heating system have seen its stable power output doubled; it now operates at the level equivalent to some 140,000 microwave ovens.
The Chinese reactor is one of a number of fusion experiments currently operating or being developed around the globe. In the U.S., for example, there are the DIII-D tokamak in San Diego, California, and the National Spherical Torus Experiment in Princeton, New Jersey.
Both of these experiments will feed into the International Thermonuclear Experimental Reactor (ITER), which is currently being constructed in the south of France.
When ITER is complete, it will become the world's largest experimental tokamak; its already-planned successor, "DEMO", is expected to be one of the first ever fusion reactors to actually produce electricity.
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