Researchers at the Joint European Torus (JET) facility in Oxford, UK, have generated the highest sustained fusion energy pulse in history, producing 59 megajoules over a five-second period. The experiment, conducted in late 2021, utilized a deuterium-tritium (D-T) fuel mixture inside the machine's donut-shaped vacuum vessel. This result more than doubles the previous energy record of 21.7 megajoules set at the same facility in 1997. The UK Atomic Energy Authority (UKAEA) stated the achievement demonstrates the potential for fusion to provide a safe and sustainable low-carbon energy source. Source: Reuters

The experiment's primary significance lies in its direct applicability to the much larger International Thermonuclear Experimental Reactor (ITER), currently under construction in France. JET is a key testbed for ITER, featuring a similar vessel shape and constructed with the same plasma-facing materials, including beryllium and tungsten. According to Tony Donne, EUROfusion programme manager, the operational scenarios and physics models tested at JET can now be applied to ITER with greater confidence. The sustained five-second pulse is particularly relevant, as this duration is sufficient to test thermal equilibrium and plasma stability under conditions approaching those required for a power plant. Source: Reuters

JET is a key testbed for ITER, featuring a similar vessel shape and constructed with the same plasma-facing materials, including beryllium and tungsten.

Achieving this record required careful management of the plasma within the tokamak magnetic confinement device. The 59 megajoule output corresponds to an average fusion power of approximately 11 megawatts (MW) over the five-second discharge. While this is a record for total energy, it is not a record for peak power. The 1997 JET experiment achieved a higher peak power but could not sustain it. This new result demonstrates a critical advance in plasma control and heat exhaust management, which are essential for maintaining the high-temperature conditions necessary for fusion reactions without damaging the reactor's internal components. The EUROfusion consortium, which comprises 4,800 experts across Europe, coordinated the research campaign. Source: Reuters

The successful D-T campaign at JET provides a crucial dataset for the next stage of fusion development. Ian Chapman, CEO of the UKAEA, noted that the results are a clear demonstration that the scientific and engineering foundations for fusion power are solid. The data will be used to finalize the operational plans for ITER, which aims to be the first fusion device to produce a net energy gain, targeting 500 MW of fusion power from a 50 MW input. The JET experiments validate the choice of materials and the plasma physics models that predict ITER's performance, reducing the project's technical risk as it moves toward its own first plasma and eventual D-T operations. Source: Reuters