Researchers at the UK Atomic Energy Authority's Culham Science Centre have achieved a new world record for fusion energy output from the Joint European Torus (JET) tokamak. In a late 2021 experiment, the device produced a total of 59 megajoules of heat energy from a sustained fusion reaction lasting five seconds. This result, announced by the EUROfusion consortium, surpasses the previous 21.7 megajoule record set by JET in 1997. The experiment operated with an average power output of approximately 11 megawatts (thermal) over the five-second pulse, demonstrating stable plasma confinement and sustained reaction kinetics in a machine environment designed to inform its larger successor, ITER. Source: Channel 4 News
The experiment, part of JET's final deuterium-tritium (D-T) campaign before its scheduled decommissioning, was designed specifically to test operational scenarios for the ITER project under construction in France. A critical aspect of the test was the use of a beryllium and tungsten inner wall for the vacuum vessel, mirroring the materials chosen for ITER. The ability to maintain a stable, high-performance plasma for five seconds without significant material degradation or plasma contamination validates these material choices and provides critical data for ITER's operational playbook. According to UKAEA CEO Ian Chapman, the results are a strong confirmation that the design and physics basis for the next-step device are sound. Source: Channel 4 News
A critical aspect of the test was the use of a beryllium and tungsten inner wall for the vacuum vessel, mirroring the materials chosen for ITER.
While the 59 megajoule output represents a significant scientific achievement, the experiment did not achieve net energy gain. Dr. Joe Milnes, Head of Operations at the Culham Centre for Fusion Energy, stated that approximately 50 megawatts of heating power were required to produce the 11 megawatt fusion power output, yielding a Q_plasma value of approximately 0.22. This is consistent with the design limitations of JET, which was never intended to reach breakeven (Q=1) or ignition. The primary goal was to sustain a D-T plasma at high power for as long as possible to study plasma-wall interactions, alpha particle heating, and control schemes under reactor-relevant conditions. Source: Channel 4 News
This milestone at the Joint European Torus concludes over two decades of research and upgrades since its last D-T experiments. The data gathered from this final campaign will be analyzed for years, directly influencing the research plan for ITER, which is designed to produce 500 MW of fusion power from 50 MW of input power, targeting a Q value of 10. The successful demonstration at JET provides confidence that ITER can achieve its goals and serves as a capstone achievement for the European fusion research program and its international collaborators. The results from this record-setting pulse will inform the operational strategies for bringing ITER online and navigating its own D-T campaigns later this decade. Source: Channel 4 News