JET’s final tritium experiments yield new energy record

See press release from United Kingdom Atomic Energy Authority here.

See press release from the EUROfusion Consortium here.

GARCHING and OXFORD (8 February 2024) – 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.

Three phases of the plasma pulse of JET that produced 69 megajoules of fusion energy. Credit United Kingdom Atomic Energy Authority / EUROfusion.

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 Antti Hakola, EUROfusion Tokamak Exploitation Deputy Task Force Leader from VTT: “We demonstrated how to tame the intense heat flowing from the plasma to the exhaust but also showed how to stabilize the plasma edge to prevent bursts of energy reaching the wall. All this is vital in protecting 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. In addition, in this series of experiments, JET successfully commissioned a novel method to monitor the tritium inventory in the device. This is an instrumental safety issue when progressing towards ITER and fusion power plants.”

Divertor is the plasma-facing component that receives the highest heat load in a fusion reactor. Photograph of a JET divertor tile after it had the letters JET and a heart engraved into it using LID-QMS. With the help of optimized laser pulses, LID-QMS can reveal the tritium content of the surface layers of wall components inside fusion reactors. © United Kingdom Atomic Energy Authority.

Over 300 scientists and engineers from EUROfusion – a consortium of researchers across Europe – contributed to these landmark experiments at the UK Atomic Energy Authority (UKAEA) site in Oxford, showcasing the unparalleled dedication and effectiveness of the international team at JET.

The JET control room on the day of final plasma experiments. Credit United Kingdom Atomic Energy Authority / EUROfusion.

Research Professor Tuomas Tala from VTT: “It is really great that many FinnFusion scientists participated in JET’s final deuterium-tritium experiments (DTE3), where high fusion power was consistently produced for 5 seconds, resulting in a ground-breaking record of 69 megajoules of fusion energy. using a mere 0.2 milligrams of fuel. The role of FinnFusion scientists in JET, beyond setting a new record, was on understanding of fusion physics and Deuterium-Tritium isotope scaling. The analysis and modelling efforts of the JET DT experiments will continue in 2024 by the FinnFusion scientists.”

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

JET concluded its scientific operations at the end of December 2023.

Dr Pietro Barabaschi, ITER Director-General: “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.”

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. As it transitions into the next phase of its life cycle for repurposing and decommissioning, a celebration in late February 2024 will honour its founding vision and the collaborative spirit that has driven its 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.