On 20 May, the world will witness a welcome staging post in the quest to develop nuclear fusion, when Germany’s Max Planck Institute for Plasma Physics switches on the Wendelstein 7-X, an earth-bound machine built to mimic the way in which stars generate energy.
The project is part of the German national fusion research programme but has received significant support at nearly 30 per cent of the total cost from the EU’s Euratom programme.
Despite its schedule slipping eight years, from 2006 to 2014, and the cost doubling from an original €500 million to more than €1 billion, the anticipation among fusion scientists is palpable.
Eventually, it is hoped, the Wendelstein 7-X will provide a baseline for a future commercial power plant that like the sun and the stars derives energy from the fusion of atomic nuclei.
Encased in a chamber and surrounded by high-precision equipment, the Wendelstein 7-X will try to produce a searing hot cloud of hydrogen that will be lashed with electricity and radiation.
The result will be the tremendous heat and energy of a synthetic star – more than ten times hotter than the sun’s core – and controlled by superconducting magnets, because no physical item could hold such a thing.
“It’s the culmination of a fascinating physics story,” said Andreas Dinklage, scientist at Max Planck and project leader for Europe’s fusion association (EUROfusion).
It’s also something of a comeback: the Wendelstein 7-X belongs to a class of fusion devices called stellarators which reigned supreme from the 1950s to the 70s. They fell out of favour as a result of the remarkable success of a reactor type called the tokamak, used today in the world’s largest fusion experiment, the International Thermonuclear Experimental Reactor (ITER).
Why is the stellarator back? The scientific director of Wendelstein 7-X, Thomas Klinger, once described both machines as, "terrible beasts.”
“Ours is a beast to build; [the tokamak] is a beast to operate," he said.
While there are different routes to nuclear fusion there is one common difficulty: how to master the extremely punishing conditions needed for it to work.
Whether you’re working with a tokamak or a stellarator, learning the long list of do’s and don’t’s from the Wendelstein 7-X experience will be invaluable for the fusion community, says ITER’s chief physicist, David Campbell.
“There’s a lot of cross-fertilisation. Testing the software they developed for simulating plasma behavior against what we’ve got will be interesting and useful,” he said. “On the engineering side, it’s going to be interesting to learn from their operational experience too.”
The Max Planck Institute of Plasma Physics named its machine Wendelstein after a 1,838-metre high mountain in the Bavarian Alps. For many, the association with an uphill climb is apt: fusion has remained stubbornly elusive.
The most audacious fusion reactor, ITER, currently under construction in Southern France, has been falling behind schedule and running over budget almost since it began.
After decades of preparation, it’s due to clock in as the most expensive scientific instrument ever assembled, with some €15 billion already spent. In March, Stefano Chiocchio, ITER’s head of design integration, told the New Yorker magazine that even a delay of a day costs close to €1 million.
Complicated physics and engineering is one thing but then there’s the effort of coordinating it all. Organising big science is a big challenge.
With ITER, especially so. None of the thirty five partners has full control of the complex jigsaw, and there is no overall central budget. As a model for future scientific cooperation, many suggest ITER’s makeshift structure is best avoided. It even requires its own currency – the ITER unit of account.
“We have a pretty established framework in Europe for international research,” says Campbell. “When you take it and extend it, it’s more complex. With ITER, we’re implementing a large scale project under a novel organisational structure.”
Despite its difficulties, the painstaking work of ITER’s scientific installation continues. Construction is being geared towards 2020 – when experiments are due to start. Fusion fuels will be added in 2027 after years of testing.
“The whole manufacturing experience can throw up some issues – assembly is quite a challenge when components are coming in from all over the world,” admits Campbell, “but we have a lot of design under our belts already.”
The supporters of ITER take a different view on costs and delays in nuclear fusion’s research.
Some commentators note that fusion’s ballooning costs are dwarfed by global subsidies to renewables, of $45 billion dollars, and subsidies to fossil fuels, of some $500 billion.
There will also be environmental benefits. Fusion is a clean energy, generating no carbon dioxide and only small amounts of radioactive waste.
There’s also a built-in negative effect of a public support that waxes and wanes on ITER and this can affect the whole fusion enterprise, says Dinklage.
“Fusion is frequently accused of taking too long – this may become a self-fulfilling prophecy with policymakers delaying funding decisions,” he said.
But overall, scientists appear happy with the level of planning and money the EU is bringing to the table.
“EU funding is at a pretty healthy level,” said Campbell. He’s particularly happy that Europe is already laying the basis for life after ITER. “There’s a very forward looking perspective. They’re even looking beyond ITER to DEMO [DEMOnstration power plant] in 2040,” he adds.
“Funding from the EU is adequate,” agrees Duarte Borba, senior adviser in the widely-praised JET (Joint European Torus) tokamak project. “For the longer term, my opinion is that fusion coming to the market will obviously require a step-up in funding and investment from industry though.”
In Horizon 2020, the EU’s largest research programme, €636 million is set aside for nuclear fusion research. A separate pot of €2.5 billion is earmarked for ITER.
The newly created EUROfusion consortium, the umbrella organisation of Europe’s fusion research laboratories, is charged with manning the EU’s fusion research coffers: the so-called Euratom funding.
The European Commission says the rationale for creating EUROfusion is to bring about an, “even more effective pooling of national research efforts” for, “increasingly complex and large-scale projects” like ITER.