What is nuclear fusion? JET reactor breakthrough, new energy power record and links to ITER facility explained

Fusion is a ‘huge step’ closer after an experiment produced world record results and demonstrated safe, low-carbon energy

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Fusion energy is a “huge step” closer after more than doubling the promising results of a successful test that took place over 30 years ago.

With no greenhouse gas emissions and abundant fuels, fusion can be a safe and sustainable part of the world’s future energy supply, scientists suggest.

If perfected, fusion energy has the potential to be a virtually unlimited supply of low-carbon energy, and would usher in an era of plentiful green energy at a time of worsening climate chaos.

But what exactly is fusion energy, how did the latest experiment work, and what does it mean for the planet?

Here is everything you need to know about it.

What is fusion energy?

Fusion energy is based on the same principle by which stars create heat and light; when light atoms merge to form heavier ones, a large amount of energy is released.

To do this on Earth, a few grams of hydrogen fuels are heated to temperatures 10 times hotter than the centre of the sun, forming a product – called plasma – in which fusion reactions take place.

Researchers say it is a power worth striving for, with one expert saying it is a source of energy that “helps protect the planet for future generations”.

What happened in the experiment?

Fusion energy is a ‘huge step' closer after a landmark experiment produced world record results and demonstrated its potential to deliver safe and sustainable low-carbon energy (Photo: EUROfusion/PA)Fusion energy is a ‘huge step' closer after a landmark experiment produced world record results and demonstrated its potential to deliver safe and sustainable low-carbon energy (Photo: EUROfusion/PA)
Fusion energy is a ‘huge step' closer after a landmark experiment produced world record results and demonstrated its potential to deliver safe and sustainable low-carbon energy (Photo: EUROfusion/PA)

On Wednesday (9 February) the UK Atomic Energy Authority (UKAEA) announced the world’s largest and most powerful operational reactor had produced a world record total of 59 megajoules of heat energy.

Over a five second period, the Joint European Torus (JET) at the UKAEA site in Oxford more than doubled previous power output records achieved in 1997.

It used the same fuel mixture that could theoretically be put to use in any future commercial fusion energy power plants.

However, the peak power of 16 megawatts achieved briefly in 1997 has not been achieved in recent experiments as the focus has been on sustained fusion power.

Tony Donne, EUROfusion programme manager, said: “If we can maintain fusion for five seconds, we can do it for five minutes and then five hours as we scale up our operations in future machines.”

Why is fusion important?

Scientists are keen to harness the power of fusion energy on Earth, as doing so has the potential to provide near limitless green energy for the planet.

Ian Chapman, the UKAEA’s CEO, said: “It’s clear we must make significant changes to address the effects of climate change, and fusion offers so much potential.

“These landmark results have taken us a huge step closer to conquering one of the biggest scientific and engineering challenges of them all.

The harnessing of fusion energy would deliver “a low carbon, sustainable source of baseload energy that helps protect the planet for future generations.

Our world needs fusion,” Chapman added.

A commercial fusion power station would use the energy produced by fusion reactions to generate electricity.

In order to produce JET’s record breaking energy levels, researchers used only 0.1 milligrams of two different forms of hydrogen – the most abundant element in the universe.

To produce the equivalent output using established fossil fuels, it would compare with burning one to two kilos of fuel.

When could fusion energy be commonplace?

Researchers say the achievement is a major step forward on fusion’s road map as a safe, efficient, low carbon means of tackling the global energy crisis.

But harnessing and reining in the forces involved is notoriously difficult, as at the heart of a fusion reactor is a super-hot cloud of electrically charged gas, or plasma, many times hotter than the sun’s core.

Following the landmark experiment, Professor Sue Ion, Fellow of the Royal Academy of Engineering, said: “Efforts must now concentrate on the very significant engineering and materials challenges which are still to be overcome before fusion can be considered a realistic and reliable energy source.”

Ian Fells, Emeritus Professor of energy conversion at the University of Newcastle, thinks fusion could be commonplace within just a couple of decades.

“10 to 20 years could see commercialisation,” he said. “Fusion was initiated with the explosion of the hydrogen bomb in 1952, its potential was realised but it has taken until now to achieve five seconds of fusion, a formidable success.

Chapman said researchers have a high confidence that Iter - a larger and more advanced fusion research project based in the south of France - will reach its goal to produce a 10-time power gain.

“That machine will turn on in a few years’ time,” he said, “so the progress is really impressive in our field.”

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