The Joint European Torus (JET), one of the world’s largest and most powerful fusion machines, has demonstrated the ability to reliably generate fusion energy, whilst simultaneously setting a world-record in energy output.

These notable accomplishments represent a significant milestone in the field of fusion science and engineering.

In JET's final deuterium-tritium experiments (DTE3), 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.

Comparison of fusion energy results in 1997 (DTE1), 2021 (DTE2) and 2023 (DTE3) on the JET tokamak.

JET is a tokamak, a design which uses powerful magnetic fields to confine a plasma in the shape of a doughnut. Most approaches to creating commercial fusion favour the use of two hydrogen variants – deuterium and tritium. When deuterium and tritium fuse together they produce helium and vast amounts of energy, a reaction that will form the basis of future fusion powerplants.

Dr Fernanda Rimini, JET Senior Exploitation Manager, said:

"We can reliably create fusion plasmas using the same fuel mixture to be used by commercial fusion energy powerplants, showcasing the advanced expertise developed over time."

Professor Ambrogio Fasoli, Programme Manager (CEO) at EUROfusion, said:

"Our successful demonstration of operational scenarios for future fusion machines like ITER and DEMO, validated by the new energy record, instil greater confidence in the development of fusion energy. Beyond setting a new record, we achieved things we’ve never done before and deepened our understanding of fusion physics."

Dr Emmanuel Joffrin, EUROfusion Tokamak Exploitation Task Force Leader from CEA, said:

"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."

Record JET discharge No. 104522 during the DTE3 experimental campaign. Credit: EUROfusion consortium

Involvement of Polish researchers

More than 300 researchers and engineers from EUROfusion, a research consortium that brings together scientists from all over Europe, including the Institute of Plasma Physics and Laser Microfusion (IPPLM) staff, took part in these groundbreaking experiments at the headquarters of the UK Atomic Energy Authority, UKAEA) in Oxford, showcasing the unparalleled dedication and effectiveness of the international team at JET.

Dr. Agata Chomiczewska, IPPLM professor, national coordinator of the JET tokamak research, said:

"Our determination and international cooperation have produced exceptional results that represent a milestone in fusion energy research. This success not only confirms the ability to control plasma in tokamaks, but also represents a key step towards achieving the goal of commercial-scale energy production using nuclear reaction. There are still many challenges and years of research ahead of us, but I am convinced that our hard work will bring even more innovative solutions that will shape the global energy industry."

Map of countries and research centers being part of the EUROfusion consortium. Credit: EUROfusion consortium

Unique significance of JET

The results solidify JET’s pivotal role in advancing safe, low-carbon, and sustainable fusion energy.

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. It has a critical role in bringing us closer to a safe and sustainable future."

Dr Pietro Barabaschi, ITER Director-General, said:

"Throughout its lifecycle, JET has been remarkably helpful as a precursor to ITER: in the testing of new materials, in the development of innovative new components, and nowhere more than in the generation of scientific data from Deuterium-Tritium fusion. The results obtained here will directly and positively impact ITER, validating the way forward and enabling us to progress faster toward our performance goals. On a personal note, it has been for me a great privilege having myself been at JET for a few years. There I had the opportunity to learn from many exceptional people."

The interior of the JET tokamak. Credit: UKAEA

40 years of innovative nuclear fusion research

JET has been instrumental in advancing fusion energy for over four decades, symbolising international scientific collaboration, engineering excellence, and the commitment to harness the power of fusion energy – the same reactions that fuel the Sun and stars.
JET demonstrated sustained fusion over five seconds at high power and set a world-record in 2021. JET’s first deuterium-tritium experiments took place in 1997.

In December 2023, JET ceased operations as a plasma generating device, moving to the next phase of its operational cycle, including repurposing and decommissioning. A celebration is planned for late February 2024 that will honor his founding vision and the collaborative spirit that ensures success.

The achievements at JET, from the major scientific milestones to the setting of energy records, underscores the facility’s enduring legacy in the evolution of fusion technology.

Its contributions to fusion science and engineering have played a crucial role in accelerating the development of fusion energy, which promises to be a safe, low carbon and sustainable part of the world’s future energy supply.

The February 8, 2024, press conference announcing the record results can be viewed at: www.youtube.com

Source: EUROfusion, UKAEA