Researchers at the Culham Centre for Fusion Energy in the UK have established a new world record for energy output from a controlled fusion reaction. In its final deuterium-tritium campaign, the Joint European Torus (JET) tokamak produced 69.26 megajoules of heat from a single 5.2-second plasma pulse, averaging a fusion power of 12.5 MW. The experiment, designated pulse #104522, required only 0.21 milligrams of D-T fuel. This result surpasses the previous record of 59 MJ set by JET in 2021 and demonstrates reproducible, high-power plasma performance under conditions relevant to future commercial fusion power plants. Source: EUROfusion

The achievement is a critical validation of the tokamak concept at scale and serves as a direct dress rehearsal for the operational scenarios planned for ITER, the larger successor to JET currently under construction in France. The JET device utilizes the same D-T fuel cycle and features a similar vessel shape and materials, including a tungsten and beryllium wall, as ITER. By sustaining a high-power plasma for several seconds, the JET team has demonstrated stable control over plasma instabilities and heat exhaust management, two of the most significant challenges in magnetic confinement fusion. These final experiments provide essential data for calibrating physics models that predict ITER's performance. Source: EUROfusion

The JET device utilizes the same D-T fuel cycle and features a similar vessel shape and materials, including a tungsten and beryllium wall, as ITER.

Operating with a deuterium-tritium fuel mix is a significant step beyond the more common deuterium-only or hydrogen plasma experiments. The D-T reaction releases approximately 450 times more energy than D-D fusion and is the primary reaction targeted by most leading fusion concepts. However, it also produces high-energy 14.1 MeV neutrons, which activate vessel components and require remote handling for maintenance, a capability extensively tested during JET's operational life. The successful and repeatable generation of power with a 50-50 D-T mix in JET's ITER-like wall confirms the viability of the materials and the overall design approach for future power-producing tokamaks. Source: EUROfusion

This record marks the culmination of JET's 40-year operational history and its final experimental campaign before its scheduled decommissioning. The facility has been a cornerstone of the European fusion research program, managed by the EUROfusion consortium. The data gathered from these last high-power pulses will be analyzed for years, informing the commissioning and operational phases of ITER and the design of the DEMO demonstration power plant. The successful execution of this final experimental run provides a robust foundation for the next generation of fusion devices aiming for a net energy gain, or a Q_plasma value significantly greater than 1. Source: EUROfusion