The WEST tokamak operated by France’s Atomic Energy Commission (CEA – Commissariat à l’énergie Atomique et aux énergies Alternatives) at its Cadarache site was able to maintain a plasma for 1,337 seconds at a temperature of 50m degrees Celsius. This was a 25% improvement on the previous record achieved in January by EAST, in China which maintained plasma for 1,066 seconds at a temperature close to 70m degrees Celsius.
“WEST has achieved a new key technological milestone by maintaining hydrogen plasma for more than 20 minutes through the injection of 2 MW of heating power,” said Anne-Isabelle Etienvre, Director of Fundamental Research at CEA. “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.”
The purpose of the experiment was not only to extend the duration of the plasma but also to ensure its stability without damaging or polluting the reactor’s components. Achieving such a long plasma duration demonstrates improved control over fusion reactions, which is crucial for developing practical fusion energy systems. According to Etienvre, this indicates progress in controlling both the production and maintenance of fusion plasma.
WEST (previously Tore Supra) produced its first plasmas at the end of 2016. WEST is unique among European tokamaks thanks to its superconducting magnets, which allow for long fusion experiments. Phase 1 of WEST operation was limited to shots of tens of seconds because the lower divertor, where the hot plasma directly touches the wall of the machine, was not actively cooled. That means that the shots are limited to the time it takes for the divertor to heat up (called inertial cooling), with shot durations around tens of seconds.
In September 2021, the WEST lower divertor was fully equipped with actively cooled components, with the same technology as the ITER divertor (tungsten monoblocks) paving the way for true exploration of long-discharge operation. The WEST facility – “W (tungsten) Environment in Steady state Tokamak” – is an all-tungsten machine with long-pulse plasma capacity.
