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Cranes lift ITER’s cryostat base into the tokamak pit to begin reactor assembly.

ITER Organization

‘Got my fingers crossed.’ As ITER fusion project marks milestone, chief ponders pandemic impact

The $25 billion ITER project, which aims to build the world’s largest fusion reactor and finally demonstrate that melding together hydrogen nuclei is a viable energy source, passed a major milestone today as construction crews lifted the first major piece of the reactor, known as a tokamak, into place.

Over 2 days, a crew of about 200 carefully lifted the cryostat base, a steel dish big enough to fill a baseball diamond and weighing as much as a giant redwood tree, into the tokamak pit near Cadarache in France. The cryostat base—the single largest and heaviest tokamak component—is the bottom section of a huge metal can that will eventually contain the rest of the reactor, including the vacuum vessel, huge superconducting magnets, and cooling systems. The ITER team is racing to have all of ITER’s major components on site by the end of 2021, in order to meet a December 2025 deadline for switching on the massive machine.

ITER has been a long time in gestation. Originally dreamt up in the 1980s, it was inaugurated as an international project based in France in 2007 and now has seven partners: China, the European Union, India, Japan, South Korea, Russia, and the United States. Projected at the time to be complete in 2016 at a cost of $11 billion, a thorough review in 2016 under then-new Director-General Bernard Bigot pushed the deadline back and the budget up. But members stuck with it and Bigot has kept the project on track.

Then, as the project neared the 70% complete mark this year, the COVID-19 pandemic struck. Unlike at most major science facilities worldwide, the decision was made to push ahead. The construction process, which involves hundreds of suppliers in member states across the globe who are required to deliver components at exactly the right time, would fall apart if forced to stop and restart. Most of the 2000 office-based staff were sent home to telework and those on the work site trimmed from 2500 to 700 essential workers.

Although construction has continued, delays have compounded on the already tight schedule. Next month, the ITER Council, which represents the member states, will meet—most likely remotely—and Bigot will ask it to make some tough decisions.

ScienceInsider spoke with Bigot this week as the cryostat base still hovered over the tokamak pit on the end of a crane. The interview has been edited for clarity and brevity.

Q: What’s the status of the cryostat base installation?

A: We started at 7 a.m. and checked everything was under control. The base was lifted above the top floor of the tokamak building to lower inside. I expect it to be in position tonight. It was an amazing exercise with very high precision and has gone smoothly so far.

Q: How does it feel to finally be at the start of tokamak assembly?

A: When you’ve been working for years and years on something and see it start to become real, you do feel a little bit of excitement. You also feel your responsibility: With the trust of so many people you feel very responsible.

Things are progressing as expected. With the welcoming of toroidal field coils [17-meter-tall superconducting magnets], we feel more and more confident that our strategy was the right one. But there’s still a lot to do.

Q: What’s the next step in assembly?

A: Next is the lower [cryostat] cylinder. It’s a can and it must be welded to the base, which will be very challenging and [will] finish in July. Then we will receive components to start vacuum vessel installation. Sector six [a 40° slice like an orange segment] arrives from [South] Korea at the end of July and toroidal field coils 12 and 13 from Japan are now at sea and will arrive in mid-June. We must assemble these three pieces together with their thermal shielding. That’s the main objective in the coming months.

Q: How has ITER managed to keep working during the COVID-19 lockdown?

A: We faced this quite early. China is a major partner and we saw the propagation of the virus there. China nearly stopped. We thought about how to continue. To stop and start again would be a nightmare. We decided to continue, but slowed down. We put barrier measures in place: physical distancing, hand washing, masks. We implemented this very early and members were supportive of the strategy.

Q: Have there been many COVID-19 cases among the staff?

A: We were lucky not to have a single coronavirus infection. Visitors were arriving continuously but we took precautionary measures. Some have shown symptoms but none were confirmed cases.

Q: Which parts of the project have been worst affected by the lockdown?

A: The part most affected is the delivery by Europe of five vacuum vessel sectors. It’s a large consortium, much of it in Italy, and components need to be moved from Italy to Germany or Spain and back to Italy. Some workshops in Italy had to stop. The companies have been keen to find recovery measures, but it’s too early to estimate the impact.

Q: When the ITER Council meets next month, what will you tell them about the project’s ability to meet the deadline?

A: I will provide a note to the council on coronavirus impact, which I’ll prepare a month from now. I feel the impact will be difficult to recover from if the vacuum vessel is delayed beyond the end of 2021. The toroidal field coils, and eight of the nine vacuum vessel sectors, have not been impacted; [South] Korea did not shut down but continued working with no delay. But in Europe there has been some delay.

So the ITER Council will decide: Keep going with extra cost, or extend by around 1 year with little cost impact.

Q: What would be the cost of extending the schedule by 1 year?

A: It’s too early to say, but we are now [spending] at around €1 million per day minimum, so 1 year would be very significant.

Q: And what would be the impact if there is a resurgence of COVID-19?

A: The impact would be very severe. I’ve got my fingers crossed that we never see another coronavirus wave.