The Joint European Torus (JET) has set a new world record for fusion energy production, generating 69.26 megajoules in a single pulse during its third and final deuterium-tritium experimental campaign (DTE3). The record-setting discharge, sustained for 5.2 seconds, was achieved on October 3, 2023, just prior to the facility's formal decommissioning at the end of the year. Operated by the EUROfusion consortium at the UK Atomic Energy Authority (UKAEA) site in Culham, JET's final experiments were designed to validate operational scenarios and physics models critical for the next-generation ITER tokamak. This result surpasses JET's previous record of 59 megajoules set in 2021, demonstrating reproducible, high-fusion-power performance. Source: EUROfusion

The achievement is significant not only for the total energy produced but for the demonstration of stable plasma control under conditions approaching those of a burning plasma. The 69.26 MJ output was achieved with an average power of 12.5 MW over the 5.2-second flat-top portion of the pulse, consuming just 0.21 milligrams of D-T fuel. A key objective of the DTE3 campaign was to manage the transition from externally heated plasmas to those significantly self-heated by alpha particles, a core requirement for future power plants. Researchers successfully demonstrated techniques to mitigate plasma instabilities and manage heat exhaust using the device's ITER-like wall, which is composed of beryllium and tungsten. These experiments provide a direct operational playbook for the ITER project. Source: EUROfusion

The achievement is significant not only for the total energy produced but for the demonstration of stable plasma control under conditions approaching those of a burning plasma.

JET's four decades of operation have been instrumental in advancing the tokamak concept, culminating in these final high-performance D-T runs. As the only operational tokamak capable of handling a D-T fuel mix with an ITER-like wall configuration, its data is irreplaceable for benchmarking the complex physics models that underpin ITER's design and operational strategy. According to EUROfusion Programme Manager Ambrogio Fasoli, the sustained power production demonstrates the advanced understanding developed over the facility's lifetime. The experiments confirmed predictions from sophisticated models, increasing confidence in ITER's ability to achieve its target of Q=10. The results from over 300 scientists and engineers involved in the campaign are now being analyzed and will be published in forthcoming peer-reviewed papers. Source: EUROfusion

The legacy of JET extends beyond a single energy record. The facility has served as a critical training ground for generations of plasma physicists and engineers, many of whom are now leading efforts at ITER and in the growing private fusion sector. The operational experience gained, particularly in handling tritium and managing neutron-activated components via remote handling, provides a unique and invaluable knowledge base. Tim Luce, Chief Scientist for the ITER Organization, noted that the DTE3 experiments directly impact ITER's research plan by demonstrating essential plasma control schemes and validating heat-load management strategies. With JET's shutdown, the global fusion community's focus now shifts entirely to the construction and eventual operation of ITER in France as the next major step in public-sector tokamak research. Source: EUROfusion