JET: An ITER-like wall and experiments with tritium
The Joint European Torus (JET), located at Culham Centre for Fusion Energy in the UK was the world's largest and most powerful tokamak between 1983 and 2023, and the focal point of European fusion research.
Designed to study fusion in conditions approaching those needed for a power plant, it was the only device capable of handling the deuterium-tritium fuel mix that will be used in ITER and in later fusion power plants. Since first plasma in 1983, milestones at JET have included the world's first controlled release of deuterium-tritium fusion power (1991) and the world record for fusion power (16 megawatts in 1997).
In more recent years, the program's primary task was to prepare for the construction and operation of ITER by acting as a test bed for ITER technologies and plasma operating scenarios:
* upgraded with an ITER-like beryllium and tungsten wall and additional heating power, JET enabled scientists to develop plasma scenarios that resembled as closely as possible those planned for ITER, investigate the interaction of the plasma with wall materials, and study the accumulation of tungsten from the wall in the plasma core;
* experiments to characterize the melting behaviour of tungsten run on the JET divertor provided valuable physics data input for the ITER divertor strategy (the choice to install a tungsten divertor from the start) and informed divertor physics in advance of ITER operation;
* with ITER-like regimes of plasma operation, scientists had the opportunity to study plasma instabilities such as ELMs (see DIII-D) and develop methods to predict and mitigate these instabilities;
In 2021, JET kicked off its planned scientific campaign with deuterium-tritium (D-T) plasmas and obtained excellent results (see all information here and here). These experiments (the first to use tritium at JET since 2003) were an important "dress rehearsal" in preparation for ITER's operation with tritium. After a final campaign in autumn 2023, JET moved to repurposing and decomissioning in 2024.
Read more about JET here.