Nuclear Fusion: New World Record at Cadarache

On February 12, the WEST tokamak at the CEA successfully sustained a plasma for over 22 minutes. This new world record surpasses the previous one set in January by the EAST experimental fusion reactor in China.

After setting a record in mid-2024, the experimental fusion reactor WEST has now pushed the limits further by achieving the longest plasma confinement time on February 12. Researchers at the CEA in Cadarache managed to sustain this plasma within the tokamak for just over 22 minutes—precisely 1,337 seconds. These results are promising for nuclear fusion research, as this latest test campaign improved the plasma confinement duration by 25% compared to the previous record set by the EAST fusion reactor in China.

Plasma Confinement Time and Fusion Power

In the field of magnetic confinement fusion, two key factors determine the “health” of the plasma—the environment that sustains nuclear fusion reactions. The first is plasma confinement time, which this record has extended. The second is fusion power output, which must exceed the input power required to heat and sustain the plasma.

Thanks to superconducting coils, actively cooled plasma-facing components, and, most importantly, decades of CEA expertise in operating tokamaks, the WEST reactor was able to sustain a hot plasma (reaching several tens of millions of degrees Celsius) for an extended period, with 2.6 gigajoules of input energy. “WEST has reached a significant technological milestone by sustaining a hydrogen plasma for over twenty minutes using 2 MW of heating power. Experiments will continue with increased power input,” explains Anne-Isabelle Étienvre, Director of Fundamental Research at the CEA.

#Fusion🔥| 1ère mondiale pour l’énergie de fusion !

👀Nouveau record obtenu dans le tokamak WEST, opéré sur le centre CEA de Cadarache : il a maintenu un plasma de fusion chaud de plusieurs dizaines de millions de degrés pendant 22 minutes avec 2,6 gigajoules d’énergie injectée. pic.twitter.com/mZgk2HTlb1

— CEA (@CEA_Officiel) February 18, 2025

Nuclear Fusion Research Worldwide

Several fusion research reactors exist around the world. In addition to WEST, notable examples include JET in the United Kingdom, a tokamak shut down at the end of 2023 that still holds the record for fusion power output. Other major reactors include JT-60SA in Japan, EAST in China, and KSTAR in South Korea.

All of these reactors contribute to the global effort in fusion research, primarily benefiting ITER, the most ambitious nuclear fusion project, also located in Cadarache and involving over 35 countries. ITER is the world’s largest experimental fusion reactor, aiming for its first plasma by 2034.■