Nuclear fusion: WEST beats the world record for plasma duration!

1,337 seconds: that was how long WEST, a tokamak run from the CEA Cadarache site in southern France and one of the EUROfusion consortium medium size Tokamak facilities, was able to maintain a plasma for on 12 February. This was a 25% improvement on the previous record time achieved with EAST, in China, a few weeks previously.

Reaching durations such as these is a crucial milestone for machines like Iter, which will need to maintain fusion plasmas for several minutes. The end goal is to control the plasma, which is naturally unstable, while ensuring that all plasma-facing components are able to withstand its radiation without malfunctioning or polluting it. 

This is what CEA researchers intend to achieve and what explains the current record. Over the coming months, the WEST team will double down on its efforts to achieve very long plasma durations – up to several hours combined – but also to eat the plasma to even higher temperatures with a view to approaching the conditions expected in fusion plasmas. 

WEST is a CEA facility that benefits from the commission’s decades of experience in the use of tokamaks to study plasmas. It welcomes researchers from around the world, who make use of its key characteristics that allow long-duration plasmas, particularly its superconducting coils and actively cooled components. WEST is one facet of an international movement comprising other major experiments in which CEA researchers are heavily involved, such as JET, the Joint European Torus tokamak in the United Kingdom (closed in late 2023), which holds the record for fusion energy, JT-60SA in Japan, EAST in China, and KSTAR in South Korea, not to mention the flagship machine that is ITER. 

For Anne-Isabelle Etienvre, Director of Fundamental Research at the CEA: “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.” 

What is fusion used for?
Nuclear fusion is a technology with the ultimate goal of controlling naturally unstable plasma. It uses even fewer resources and less fuel than fission, which was already very concentrated, and does not produce long-lived radioactive waste.  Of the various possible techniques for generating energy, the most advanced is magnetic confinement fusion1, where plasma is held in a torus by an intense magnetic field and heated until the hydrogen nuclei fuse. Confinement fusion has been shown by JET to produce fusion power of 15 MW for several seconds.

France, home to both WEST and ITER, is well-placed to house the first prototype nuclear fusion reactor. Nuclear fusion is a source of energy that exploits nuclear reactions, with many possible complementary aspects with nuclear fission energy and associated techniques relating to neutrons and matter, which are well understood.

Nevertheless, given the infrastructure needed to produce this energy on a large scale, it is unlikely that fusion technology will make a significant contribution to achieving net-zero carbon emissions by 2050. For this, several technological sticking points need to be overcome, and the economic feasibility of this form of energy production must still be demonstrated. 

About the CEA
The CEA is a unique public research body whose raison d’être is two-fold: it helps public policymakers to make informed decisions, and it gives French and European companies – as well as local authorities – the scientific and technological tools they need to face the major societal changes related to the digital and energy transitions, the future of health care, and global defence and security. Its action is based on three key values that drive the CEA teams in their daily work: curiosity, cooperation, and a keen sense of responsibility.  To find out more: www.cea.fr/english