The nuclear-fusion project proving that multilateral collaboration still works

“In a few years this will be the hottest place in the known universe,” says Sabina Griffith, a communications officer for international research and engineering organisation Iter, gesturing at a huge metal pillar. monocle is in a cavernous assembly hall located about 30km north of Aix-en-Provence, staring at a partially constructed tokamak, a type of fusion reactor that might provide a panacea for the world’s energy problems. The heat inside tokamaks – which can reach about 150,000,000c, or 10 times as hot as the core of the sun – pushes atoms to fuse, which generates vast amounts of energy. Crucially, they produce negligible carbon emissions and almost no radioactive waste.

Iter, originally known as the International Thermonuclear Experimental Reactor, is developing one such device that has been described as “the sun in a bottle” because of its enormous power. Upon completion, it will be the largest tokamak ever made, weighing 23,000 tonnes, about twice as much as the Eiffel Tower, and generating 500 megawatts of power – enough to provide energy for as many as 500,000 homes. “We are challenging mother nature’s forces,” says Griffith.

For now, however, Iter’s tokamak remains a work in progress, crisscrossed with hundreds of pieces of scaffolding and attended to by 2,000 engineers and scientists, and more than 1,000 construction workers. The project is pushing the boundaries not just of science but also of multilateral co-operation: the workers here represent the brightest and best from 33 countries, including the US, China, Russia, the EU member states, Japan, South Korea and India. However, as a result of logistical, bureaucratic and scientific challenges, Iter is currently well behind schedule. Originally set to be turned on this year, the prototype is now due to come online in 2034.

At a time when there is an urgent need for large-scale carbon-free energy, the pace of Iter’s progress has been frustrating for those desperate for a technological fix to the climate crisis. In 2024 global emissions hit new heights and it was the warmest year since records began. Yet effective international co-operation to address the problem is almost non-existent. Last year the UN’s marquee climate conference, Cop29, yielded more controversy than concrete action, while countries such as the US and Germany are continuing to rely on highly polluting coal. Iter is a “moonshot” attempt to create an almost limitless, large-scale source of clean energy but it has always denied being a silver bullet. Is the problem that a fusion breakthrough is out of reach – or is Iter’s progress just slower than it could be?

A growing number of entrepreneurs think that it’s the latter. Since the advent of generative AI, fusion power has become something of a buzzword. Large language models such as Chatgpt depend on huge data centres to operate; the anticipated explosion of AI usage is expected to significantly increase the demand for electricity. As a result, technology companies have been scrambling to increase their supplies. In September 2024, Microsoft announced a 20-year-deal to restart the Three Mile Island nuclear power plant in Pennsylvania, the site of the US’s most infamous nuclear disaster. Meanwhile, several nuclear-fusion start-ups, such as Helion Energy, claim that they will be up and running within this decade.

When monocle asks Pietro Barabaschi, Iter’s director-general, about these start-ups, his face lights up. “I work in this field to make fusion a success,” he says. “If somebody succeeds, I’ll be very happy.” The Italian engineer took the helm in late 2022 after the death of his French predecessor, Bernard Bigot. Barabaschi inherited the difficult task of managing the world’s high expectations while encouraging further investment.

For now, the project resembles an expensive dream. Iter’s launch estimate of €5bn was revised up to €20bn in 2016; the US Department of Energy, a key partner, projects that its final price tag will be closer to €60bn. With the US pulling out of multilateral climate-related endeavours, Iter’s ballooning costs have caused dismay, as has its delayed completion date. And even when it’s finally activated, it won’t be plugged into the power grid, meaning that it will never provide energy to a single home. Iter’s aim, rather, is to demonstrate that it’s possible to build thermonuclear reactors that emit no carbon, create benign waste and can be turned off with the flick of a switch, making them much safer than conventional forms of nuclear power. “We have to prove that we can operate a fusion reactor safely on a large scale,” says Griffith.

Tokamaks are not a 21st-century invention. The first was built in the Soviet Union in 1951; indeed, Iter is a product of that long-dissolved nation. In 1985 the country’s final leader, Mikhail Gorbachev, proposed an international collaborative project to develop a huge thermonuclear reactor to then-US president Ronald Reagan, at a time of thawing relations between the two powers.

But 35 years after the end of the Cold War and the collapse of the Soviet Union, international co-operation is fraying to an extent that even a goal as noble as limitless clean energy seems under threat. US financial support for Iter has had its ups and downs over the years: during the Obama administration, for example, there was a stoppage of payments. Funding gradually returned during Donald Trump’s first presidency and, under Joe Biden, shortfalls from previous years were made current. Since then, however, Trump has returned to power, vowing to increase fossil-fuel extraction while rowing back on his country’s climate commitments. Is Barabaschi worried about Trump 2.0? “There are rough seas ahead,” he says. “We have to have evidence of progress. That’s really the substance.”

To the east, another of Iter’s founding nations is also at odds with its collaborators. The invasion of Ukraine has made Russia an international pariah state and the Ukrainian Academy of Sciences has called for any scientific collaboration with Moscow to stop. So, how has the war affected the project? “There has been no change,” says Barabaschi. Indeed, kicking Russia out was never on the table. The country is making crucial reactor components and, besides, there is no mechanism that allows for such a banishment. “There have been some indirect effects on execution,” says the director-general. “But this project maintains strong cohesion between all members.”

Russia has been under restrictive EU sanctions since 2022 and the additional paperwork and diplomacy required to ship components to and from the country have caused long delays. But this has not deterred Barabaschi or his colleagues. Even at the best of times, Iter’s multilateral nature means that it must contend with not only scientific but also operational and bureaucratic complexity. The participating governments are individually responsible for commissioning specific components of the reactor. Each nation must then ship these often gargantuan parts to France.

The elaborate choreography of hi-tech manufacturing and convoluted shipping is overseen by Iter’s council, within which representatives from every member government seek proof that their nation’s money is being put to good use. monocle’s visit coincides with one of their meetings. At Iter’s headquarters, a two-minute drive from the tokamak assembly hall, the red carpet has been rolled out and delegates pose for photos in front of a row of neatly arranged flags. Behind the closed doors of the council chamber, the 2025 budget is being debated. While Barabaschi makes his pitch the cafeteria line is abuzz with anxious gossip. After lunch we overhear one scientist whispering to another, in Latin, “Habemus budgetum” (“We have a budget”).

Later, at an all-staff meeting, Barabaschi announces to a relieved crowd that the necessary funding has been secured to keep the lights on for another year. After his speech he sits down with monocle in the council chamber beneath a large, atom-shaped chandelier. “I don’t have much hair left but I must have lost another few hundred today,” says the director-general, leaning back in his chair. “When I joined two years ago the situation was quite difficult.”

At the time, parts of the tokamak that had been painstakingly installed had to be removed and the project was sliding backwards. “We had to stop the assembly phase and do some important repair activities,” he says. “So 2024 was the year when we had to show that the project was back on track.”

Iter has undergone a reorganisation under Barabaschi’s leadership and, after a staff reshuffle, it was able to meet all of its spending targets for the first time last year. That was enough to seal the deal for 2025 but soon Barabaschi will need to persuade his funders all over again. “What helps,” he says, “is that everybody agrees on the importance of the goal.” Griffith chimes in, “Some very senior scientists come to our meetings. They’re more than 90 years old but they don’t give up.”

Ahead of a ceremony celebrating the arrival onsite of South Korean and European segments of the vacuum vessel – sections of the future “bottle” that will hold unimaginable heat – Barabaschi congratulates his troops on their perseverance. “Part of this vessel came from Russia and part came from India,” he says. “The Iter project was [full of] ideas on how to complicate [already] complicated affairs.” The crowd responds with knowing chuckles.

Next, we head over to the storage facility for a cake-cutting in front of the gigantic, glimmering modules. The dessert is topped with rice-paper replicas of the new components. Under the bright warehouse lights, Kijung Jung and his staff tuck in. Jung is the head of Koda, the agency that co-ordinates South Korea’s contributions to Iter, which was responsible for the delivery of four new sections. “The celebration today is really emotional for me because the manufacturing of our vacuum vessel sectors took almost 14 years,” he tells monocle. “You cannot imagine how difficult it was.”

Later, as Griffith drives us down a road that snakes through the Iter complex’s 39 buildings, she gestures towards the giant assembly hall behind us. “Less than 20 years ago this was nothing,” she says. In a speech, Reagan once praised the kind of individual “who plants trees in whose shade he will never sit”. That’s the spirit in which he teamed up with his arch-rival, Gorbachev, to launch a programme from which he knew he could never directly benefit either politically or personally. Will Iter’s tokamak be switched on in a decade as planned? How much higher will its costs climb? Barabaschi and his colleagues can only take educated guesses as they are butting up against the upper limits of human knowledge.

“This is research,” says Griffith. “It’s not like you think of something, hand it over to the industry, plug it in and then it just works.” Since Iter isn’t designed to run continuously for decades, far more research and development on factors such as the durability of materials is needed before fusion power stations can become practical. Realistically, this project won’t fix the climate crisis on its own. It might even be left in the Provençal dust by a new generation of streamlined private start-ups.

But, in important ways, Iter has already succeeded. The agency’s name isn’t just an acronym: it’s also the Latin word for “the way” and the project has charted a path for others to build on its progress and learn from its mistakes. Perhaps as importantly, at a time of darkening geopolitical clouds, it is demonstrating every day that international co-operation to address the existential threat of climate change is possible in a fractured world. To isolationists who say that multilateralism is dead, Iter offers a red-hot retort. — L
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