Your browser is out of date. Some of the content on this site will not work properly as a result.
Upgrade your browser for a faster, better, and safer web experience.

The power and the glory

ITER’s tokamak fusion reactor will ultimately weigh 23,000 tonnes

ITER’s tokamak fusion reactor will ultimately weigh 23,000 tonnes. Photo: Matjaž Krivic

The village of Culham outside Oxford (population 453) is an unlikely place to find the planet’s future energy source. But on the outskirts of this charming spot is the Joint European Torus, known as JET, the world’s oldest and largest functioning fusion nuclear reactor, which is at the heart of a project to create limitless, continuous, cheap green energy. The compound in which JET sits has also become a hub for tech start-ups: as you make your way round the site you occasionally cross paths with a driverless vehicle that pauses to allow you to cross the road.

Having made your way past one pioneering technology you arrive in the huge hall containing another, JET’s ‘tokamak’. The tokamak is the apparatus in which scientists have been attempting to mimic the process of fusion which takes place within the sun by fusing deuterium and tritium, both isotopes of hydrogen. “Right now, we are undertaking some of the most important experiments in JET’s history,” JET operations department manager Joe Milnes told me as we chatted in his office, located right next to the reactor. If these experiments help JET unlock fusion power then the implications for combatting climate change could be immense.

To trigger fusion in Culham, Milnes and his team create a temperature of 150 million degrees Celsius – ten times hotter than that at the centre of the sun – using electric currents, particle beams and radio waves. This is used to turn the isotopes into super-heated, electrically-charged plasma. Milnes and his colleagues keep this plasma suspended in a magnetic field, as there’s no material on Earth that could withstand the heat of coming into contact with it directly.

When this extraordinarily demanding set of steps is carried out correctly, deuterium and tritium can fuse together to create helium. This releases neutrons, whose energy can then be converted to electricity. It is a highly complex, technically challenging process, and one which is being observed avidly around the world. JET, which opened in 1983 and became the first to deliver deuterium-tritium power in 1991, last set the record for fusion power in 1997 when it produced 21.7 megajoules. When we spoke in October 2021, Milnes and his team were hoping to eclipse this record in a series of crucial tests. “You could say the entire international fusion community is now on the edge of their seats,” said Milnes. As well as aiming to create more power than in 1997, he wanted to sustain it for a longer period. “We are seeking to create stability,” he said.

The JET Torus Hall was completed in January 1982 and opened a year later. Its walls are three metres thick

The JET Torus Hall was completed in January 1982 and opened a year later. Its walls are three metres thick. Photo: UKAEA / EUROfusion

To Milnes’ delight, his new experiments at JET culminated in a jubilant announcement in February 2022. The tokamak set a new record for sustained fusion power: over the course of five seconds, it produced 59 megajoules of energy, a more than twofold increase from the 1997 record. In terms of output, this was not much – reportedly just enough to boil around 60 kettles, and less than the energy that was put into the experiment to create the superheated plasma. In terms of a proof of concept, however, it was a significant breakthrough.

“We seem to be on the right track. We’re making swift progress according to a very clear plan. We know exactly what we wish to achieve,” said Dr Constanza Maggi, a plasma physicist and one of JET’s senior researchers. But the work carried out by JET is just the first step. “Our fusion plan has three chapters,” said Maggi. “JET for the testing. ITER as the experimental reactor creating more energy than was put in. And then a demo plant as the vanguard of the world’s first industrial-scale fusion plant.”

The ITER (International Thermonuclear Experimental Reactor) project, a joint venture by 35 countries that between them produce 85 percent of global GDP, is the world’s most ambitious single scientific project. Its broad outlines were put in place during the final stretches of the cold war, in November 1985 at a superpower summit in Geneva. The contract regulating the implementation of the international research project was signed a year later.

Finding the right location for the reactor took a long time, and reaching a logistical and geopolitical consensus took even longer. More than a decade of technical studies, political bargaining and diplomatic fine-tuning was required before Saint-Paul-lès-Durance in Provence was finally agreed upon.

Data screens monitor progress during JET’s record-setting experiment, which produced 59 megajoules of energy, more than double the previous record produced by a nuclear fusion reaction

Data screens monitor progress during JET’s record-setting experiment, which produced 59 megajoules of energy, more than double the previous record produced by a nuclear fusion reaction. Photo: UKAEA / EUROfusion

The choice of location was finalised at the end of 2005 in Moscow at a summit of all participating countries. On 21st November 2006, the Elysée palace in Paris hosted the signing of the agreement on the construction of the world’s largest experimental fusion reactor. Six months later, the 181-hectare site saw the first construction machines swing into action.

ITER’s design has been shaped by lessons learned, components developed and materials tested at JET, while data gleaned from the experiments that concluded there in February 2022 will be used to plan its operations. “Estimates suggest ITER should cost about a million euros per day to function,” Milnes told me. “Our experiments [at JET] could significantly lower this figure, as well as shorten the period until the first plasma is produced.” ITER’s objectives are clear: to prove nuclear fusion can be used on Earth to produce cheap, carbon-free electrical energy at scale, helping mankind break its suicidal dependence on fossil fuels. The key challenge is to prove that its tokamak can deliver ten times more energy than is used to create the plasma. Once that is achieved the way is open for the creation of fusion power stations across the globe.

 ITER tokamak assembly coordinator Robert Shaw. The project employs a construction workforce of over 3,000 people

ITER tokamak assembly coordinator Robert Shaw. The project employs a construction workforce of over 3,000 people. Photo: Matjaž Krivic

Such a development can’t come soon enough: since 1973, global energy usage has doubled. Seventy percent of all carbon dioxide emissions into the atmosphere are created through energy consumption and 80 percent of all the energy we consume is derived from fossil fuels. Fusion energy holds the prospect of ending these emissions forever – along with political dependence on oil and gas-producing states.

Creating a fusion reaction is different from creating a fission reaction, the technique deployed in all existing nuclear power stations. Fission creates energy by splitting atoms, releasing neutrons and triggering a chain reaction, which can get out of control if not carefully monitored. The challenge of fusion is sustaining reactions, not containing them, and they create no radioactive waste. It is true that the idea of endless cheap energy from fusion in 30 years’ time has been doing the rounds among scientists for longer than 30 years, leading to scepticism it can ever be achieved. But the teams at JET and ITER are convinced it is now on the path to becoming a reality.

At the end of July 2020, the huge area formerly occupied by an ancient oak forest saw the beginning of the assembly of ITER’s own tokamak which, when it is complete, will have ten times the plasma capacity of JET and will weigh 23,000 tonnes. It will be surrounded by some of the largest magnets ever created. Their staggering proportions – some of them will be 17 metres tall – means they will be assembled on site, in a special hall, where you could comfortably park at least ten of the biggest cargo planes in existence.

The furious heat created by fusion will be contained inside the tokamak by the water circling the reactor and released with the help of gargantuan cooling towers. At the moment, ITER provides employment for over 3,000 construction workers, soon to increase to 4,000; housed inside the vast complex, they operate in shifts around the clock. The costs of the project have been revised up from an initial estimate of €6 billion to €20 billion, almost half of which is being funded by the EU.

What we are trying to do is like creating a small artificial sun on Earth”

Cooling towers on the roof of the ITER building, Saint-Paul-lès-Durance, France

Cooling towers on the roof of the ITER building, Saint-Paul-lès-Durance, France. Photo: Matjaž Krivic

Following the trail laid by JET, ITER will be fuelled by deuterium and tritium. Deuterium can be found in abundant quantities in both fresh and salt water – the amount found in a bathtub of water, when fused with tritium, could provide all the energy needed by one person for 60 years. In contrast very little tritium can be found in nature, so scientists are already producing it synthetically. It is an exceptionally pricey substance: a single gram currently costs around $30,000. Should nuclear fusion take off, the demand will go through the roof: it is estimated that a fusion plant with an 800 megawatt capacity will consume 300 grams per day. This is why an important part of the research conducted at ITER will be directed towards producing its own tritium, by allowing plasma neutrons created in the tokamak to react with lithium.

I met with ITER’s director general, Bernard Bigot, in late 2020. Bigot has been credited with reinvigorating the project when he took it over in 2015, at which stage it was mired in delays. “Energy is life: biologically, socially, economically,” he told me. “What we need is a sustainable energy supply. When the Earth was populated by less than a billion people, the renewable sources were sufficient for demand. Well, not any more. We embraced fossil fuels and did a lot of harm to our environment. And here we are now, eight billion strong and in the middle of a drastic climate crisis.”

“There is no alternative but to wean ourselves off our current main power source,” Bigot continued. “And the best option seems to be the one the universe has been utilising for billions of years. What we are trying to do here is like creating a small artificial sun on Earth. This fusion power plant will be in operation all the time. This sun, so to speak, will never set.”

The ITER network comprises around 4,500 companies with 15,000 employees from all over the globe

The ITER network comprises around 4,500 companies with 15,000 employees from all over the globe. Photo: Matjaž Krivic

Part of the director-general’s job is to coordinate the project’s seven senior partners – including the US and Russia – and their often differing views on the handling of political, ideological and economic issues. “Now that is truly no small feat, especially in these times,” Bigot told me with a smile. “I am tremendously lucky that all seven partners have grasped the unique opportunity provided by the construction of our reactor. All are acutely aware that fossil fuels cannot be utilised ad infinitum.”

Bigot will sadly not see his dreams become reality. On 14th May 2022 he died at the age of 72: his passing was met with an outpouring of tributes from the scientific community. Work continues apace on the manmade sun he spent years championing. If all goes to plan, a decade of testing (2025-2035) at ITER will be followed by the construction of power plants with capacities of up to four gigawatts, called ‘The DEMOnstration Power Stations’, or ‘DEMOs’ for short.

The moment when fusion-produced electrical energy starts coursing through the powerlines to supply our homes is still at least 30 years off. Given the timescales involved, none of the scientists at JET or ITER I spoke with believe that we can wait for fusion to save us from climate change and highlight the need to invest in renewables in the meantime. All, however, are motivated by the feeling of being part of something important. “We are standing on the cusp of proving once and for all that hydrogen fusion is a very real solution to the global energy crisis,” Bigot told me. “Should we prove successful it will be a remarkable feat for everyone involved.”

We hope you enjoyed this sample feature from issue #46 of Delayed Gratification

Buy issue Subscribe

More stories...

A slower, more reflective type of journalism”
Creative Review

Jam-packed with information... a counterpoint to the speedy news feeds we've grown accustomed to”
Creative Review

A leisurely (and contrary) look backwards over the previous three months”
The Telegraph

Quality, intelligence and inspiration: the trilogy that drives the makers of Delayed Gratification”
El Mundo

Refreshing... parries the rush of 24-hour news with 'slow journalism'”
The Telegraph

A very cool magazine... It's like if Greenland Sharks made a newspaper”
Qi podcast

The UK's second-best magazine” Ian Hislop
Editor, Private Eye
Private Eye Magazine

Perhaps we could all get used to this Delayed idea...”
BBC Radio 4 - Today Programme