Joint European Torus sets new fusion energy output record

The Joint European Torus (JET) has demonstrated the ability to reliably generate fusion energy, whilst simultaneously setting a world record in energy output.

A statement released by the UK Atomic Energy Agency's Culham Centre for Fusion Energy (CEA) explained that in JET’s final deuterium-tritium experiments "high fusion power was consistently produced for 5 seconds, resulting in a ground-breaking record of 69 megajoules using a mere 0.2 milligrams of fuel."

JET is a tokamak, which uses powerful magnetic fields to confine a plasma in the shape of a doughnut. The fusion reaction is created using deuterium and tritium fused together, the same fuel mixture to be used in future commercial fusion power plants.

Dr Emmanuel Joffrin, EUROfusion Tokamak Exploitation Task Force leader from CEA, commented on the announcement: “Not only did we demonstrate how to soften the intense heat flowing from the plasma to the exhaust, we also showed in JET how we can get the plasma edge into a stable state thus preventing bursts of energy reaching the wall.

"Both techniques are intended to protect the integrity of the walls of future machines. This is the first time that we’ve ever been able to test those scenarios in a deuterium-tritium environment.”

Decades of fusion development

Work began with the JET programme in 1983 with its first deuterium-tritium experiments taking place in 1997. The project demonstrated sustained fusion over five seconds at high power and set a world record in 2021 and in December 2023, officially concluded its scientific operations.

According to the CEA, JET’s research findings have critical implications not only for ITER in France – but also for the UK’s STEP prototype powerplant, Europe’s demonstration powerplant, DEMO, and other global fusion projects.

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UK Minister for Nuclear and Networks, Andrew Bowie, said: “JET’s final fusion experiment is a fitting swansong after all the groundbreaking work that has gone into the project since 1983. We are closer to fusion energy than ever before thanks to the international team of scientists and engineers in Oxfordshire."

Professor Sir Ian Chapman, UKAEA CEO, said: “JET has operated as close to powerplant conditions as is possible with today’s facilities, and its legacy will be pervasive in all future powerplants."

JET will now move into the next phase of its life cycle for repurposing and decommissioning. The CEO will host a celebration later this month to honour its success.

The plasma reaction can be viewed on the website of the UKAEA.