French fusion reactor’s 22-minute plasma record boosts energy hopes

Scientists at the CEA’s WEST facility (operated at the Cadarache center in southern France) have reached a milestone in magnetic confinement fusion research, sustaining a superheated plasma for 1,337 seconds—just over 22 minutes. Achieved on February 12, this feat outstrips the previous record set a few weeks ago by China’s EAST tokamak and marks a 25% improvement in sustained plasma duration, according to a CEA press release.

The plasma, which reached temperatures of 50 million degrees Celsius, highlights the growing maturity of long-duration plasma control. Farther out, future machines, including the international ITER project under construction nearby, may be able to sustain fusion reactions for the extended timescales needed to produce net energy gain.

“WEST has achieved a new key technological milestone by maintaining hydrogen plasma for more than twenty minutes through the injection of 2 MW of heating power. Experiments will continue with increased power. This excellent result allows both WEST and the French community to lead the way for the future use of ITER.”

Why plasma duration matters

Magnetic confinement fusion involves heating hydrogen isotopes inside a torus-shaped device (tokamak) using magnetic fields to confine the ionized gas, or plasma. The longer and more stably the plasma can be held, the closer researchers get to demonstrating the conditions necessary for energy-producing fusion reactions. Although fusion does not generate long-lived radioactive waste like nuclear fission, the challenges are considerable: confining plasma at tens of millions of degrees, preventing damage to internal reactor walls and maintaining the cleanliness of the plasma environment.

WEST—short for “W Environment in Steady-state Tokamak”—serves as a testbed for ITER technologies and operating scenarios. ITER will require plasma durations on the order of several minutes or more to prove the scientific and technological feasibility of fusion power. By pushing plasma durations beyond 20 minutes, WEST researchers aim to refine components such as superconducting magnets and actively cooled walls, providing data for ITER’s eventual operations.

Up next, higher power and longer durations

The WEST team eventually aims to push plasma discharges to even higher temperatures and potentially longer durations, targeting hours-long experiments in the future. The goal is to gain knowledge on how to stabilize plasma and manage heat loads on reactor components.

Fusion research is heating up with a string of milestones in recent years. In December 2022, the U.S. National Ignition Facility (NIF) made headlines by achieving net energy gain—producing more fusion energy than the laser energy used to initiate the reaction. That advances was successfully repeated with higher yields in July 2023. Meanwhile, the UK’s Joint European Torus (JET) set a new energy record in February 2024, generating 59 megajoules over five seconds via magnetic confinement. On the commercial front, Commonwealth Fusion Systems announced plans in late 2024 to build a grid-scale fusion power plant in Virginia, slated to be operational in the early 2030s at around 400 megawatts of capacity. Also in 2024, separate groups reported fusion performance advances. We also profiled the R&D 100 winning team at General Atomics that contributed to the 2022 NIF breakthrough.