The EUROfusion consortium has announced a new world record for fusion energy output from a single pulse at the Joint European Torus (JET) facility. In its final deuterium-tritium (D-T) experiments before decommissioning, the tokamak produced 69 megajoules of thermal energy over a five-second period. This achievement surpasses the previous record of 59 MJ, also set at JET in 1997. The experiment, conducted at the UK Atomic Energy Authority's Culham campus, required only 0.2 milligrams of D-T fuel and demonstrated stable plasma confinement under high-power conditions. The result serves as a critical validation of plasma physics models and operational scenarios developed for the next generation of fusion devices. Source: EUROfusion

The record-setting pulse sustained an average fusion power of 13.8 megawatts for its five-second duration. While this represents a significant scientific milestone, the JET device, like most contemporary magnetic confinement experiments, operates with a net energy loss. The energy required to heat the plasma and operate the machine's systems substantially exceeds the thermal energy produced by the fusion reactions, resulting in a Q_plasma value well below unity. JET's primary mission was not to achieve net energy gain but to investigate plasma behavior under reactor-relevant conditions, specifically testing materials, heating schemes, and control systems. This final campaign focused on replicating and optimizing scenarios for its larger successor, ITER. Source: EUROfusion

The record-setting pulse sustained an average fusion power of 13.8 megawatts for its five-second duration.

This achievement is the culmination of JET's DTE3 experimental campaign, which utilized an ITER-like wall composed of beryllium and tungsten. This configuration minimizes plasma contamination and fuel retention compared to the carbon wall used in earlier high-performance shots, including the 1997 record. Operating with a metallic wall presents significant plasma control challenges, and successfully sustaining a high-power D-T plasma for several energy confinement times under these conditions is a key demonstration for ITER. The data gathered from these final experiments will inform plasma start-up, heating, and control strategies, directly reducing operational risks for the multi-billion-dollar international project under construction in France. Source: EUROfusion

With the conclusion of its operational phase in December 2023, JET will now undergo a multi-year decommissioning and repurposing process. The facility's contributions span four decades, providing the fusion community with invaluable data on alpha particle heating, plasma-wall interactions, and tritium handling. The successful and repeatable performance during its final run reinforces confidence in the tokamak design as the leading concept for a commercial fusion power plant. The validation of predictive models against these experimental results is perhaps the most critical legacy for future machines aiming to achieve a burning plasma and significant net energy gain. Researchers from across the EUROfusion consortium will analyze the comprehensive dataset from this campaign for years to come. Source: EUROfusion