The EUROfusion consortium has announced a new world record for fusion energy output at the Joint European Torus (JET) facility located at the Culham Centre for Fusion Energy in the UK. In a late 2021 experiment, the tokamak produced 59 megajoules of total energy over a five-second plasma discharge. This performance corresponds to an average fusion power of approximately 11 MW during the pulse. The result more than doubles the previous record of 21.7 megajoules set at JET in 1997. These experiments serve as a critical validation of plasma physics models and operational scenarios planned for the next-generation ITER device, which is structurally a scaled-up version of JET and will use the same deuterium-tritium fuel cycle. Source: EUROfusion

Achieving this milestone required significant hardware and operational upgrades to the JET device. The original carbon-based plasma-facing components were replaced with a beryllium and tungsten 'ITER-like wall' in 2011. This change was crucial for managing the intense heat loads and minimizing plasma contamination, which are critical challenges in long-pulse, high-power D-T operations. The recent experiments were the first time JET had operated with a deuterium-tritium fuel mixture in nearly two decades. The successful management of tritium, a radioactive hydrogen isotope, and the validation of the new wall materials under reactor-relevant conditions provide essential data for the design and licensing of future fusion power plants. Source: EUROfusion

Achieving this milestone required significant hardware and operational upgrades to the JET device.

The energy gain, or Q value, for this record-setting pulse was approximately 0.33. This means the experiment produced about one-third of the energy required to heat the plasma, with the remainder supplied by external heating systems. While not achieving energy breakeven (Q_plasma > 1), the result aligns with the design limitations of the JET machine and meets the scientific objectives of the experimental campaign. The primary goal was not to achieve net energy gain, but to sustain a high-power fusion plasma for a multi-second duration, demonstrating the stability of the plasma and the performance of the upgraded machine components under conditions approaching those expected in a commercial fusion reactor. Source: EUROfusion

These results from the Joint European Torus provide the most direct experimental validation for the operational plans of ITER. As a larger device with a plasma volume roughly ten times that of JET, ITER is designed to produce 500 MW of fusion power from 50 MW of input heating power, targeting a Q value of 10. The JET experiments successfully tested high-confinement mode (H-mode) plasma scenarios and control techniques that are foundational to achieving ITER's performance goals. The data gathered on plasma stability, heat exhaust, and materials performance will be used to refine the predictive models that guide ITER's commissioning and operational phases, reducing the project's technical risks. Source: EUROfusion