Red Herring July 1, 2016
Located a ten-minute drive outside the pretty German town of Greifswald, the Max Planck Institute for Plasma Physics has a gray-and-glass front and gently waving roof that scream ‘Science Stuff Here.’
Inside, it’s not much different: bare walls, throngs of scientists drinking coffee and an Escher-pleasing warren of corridors and offices. It’s in the bowels of the giant building, however, that the Institute is protecting, updating and perfecting its greatest asset. It’s one that might, years from now, change the world.
The Wendelstein X-7 might not, at first sight, appear the likeliest candidate for global energy savior. It’s messy: pipes and platforms and wires surround it like scaffold on a car production line, something Germany has become rather more known for.
But the people here believe their contraption is a real step towards sustainable nuclear fusion power, something yearned ever more in an age of global climate change and withering fossil fuel deposits.
The history behind the Wendelstein project, is almost as radical as the machine itself.
‘STELLARATOR’ is surely one of science’s sexiest project names. But for most of the 20th century it was fusion’s poorer cousin. To begin with, the idea, first developed by Princeton University’s Lyman Spitzer in the 1951, was simple: to keep plasma from cooling and losing its energy, one could create a racetrack of magnetic coils that was twisted, to keep the plasma from hitting the sides.
“It’s like when you sit in a sailing boat,” Thomas Klinger, leader of the Wendelstein project, told Red Herring. “You have a wind blowing from the side but you also have an underground drift, and you have to steer against that drift. Only then will you arrive where you want to arrive.”
Spitzer and his acolytes believed the stellarator was the answer to Earth’s energy problems. Trouble was, the machine was an engineering and budgetary nightmare. Each part had to be bespoke, and the slightest issue spelt the end of a test.
At the same time, Soviet pioneers Andrei Sakharov and Igor Tamm had a different idea: they would run a current through a simple, donut-shaped coil that was relatively cheap to build. They called their machine the tokamak. Both devices were built in secrecy, of course. But in both camps, a Cold War race began to solve the problem of nuclear fusion.
It was a race in which the USSR quickly established a lead. Tokamaks weren’t just outperforming their western counterparts – the Stellarator was terrible. “You couldn’t get the plasma hot in there,” said Klinger, who has a debonair look combining a sharp suit and hat. “Something was really wrong.”
Research groups worldwide began switching to tokamaks in the 1970s and it was widely thought the stellarator project was dead. Even at Princeton, the stellarator’s spiritual home, the idea was largely scrapped. Tokamak evolution recently culminated in the giant ITER project in France, a €16 billion ($17.8 billion) effort to build a tokamak that can produce more energy that is put in.
But throughout that period, two countries remained, as Klinger puts it, “stubborn.” Since 1998 Japan has housed the Large Helical Device (LHD) in the city of Gifu, while Germany pressed on with Wendelstein. Before, stellarator coils were a figure-eight shape. The LHD has kept faith in that design, and has produced results on par with the latest tokamaks.
The Germans went down another, key route.
“If you take the first set of coils, and you create the twist not by doing a figure-eight, but by adding an additional set of coils – the most common approach is to have a double-helix,” said Klinger. “If you run counter-directed currents around this double-helix, you are creating a quadropole field, which creates the twist.”
In reality that gives the Wendelstein 7-X the appearance of a mad, Dadaist quoit. “With a tokamak you can make a vertical cut at any position and the cross-section always looks the same,” Klinger said. “If you do the same to a stellarator, depending on where you cut, you will get very different shapes. And this symmetry has a lot of mathematical implications, on the particles.
“In physics we have one golden rule: symmetry creates conserved quantities,” he added. “And so this lack of symmetry turned out to be one very, very big problem with stellarators.” A taskforce was thrown together to find some kind of stellarator symmetry. Soon enough, they found it: a quasi-symmetry, but symmetry nonetheless.
But there was another problem. The designs the Wendelstein required were far too complex for ordinary pen and paper drawings. Fortunately, the project coincided with the development of supercomputers that could do the job. Klinger pointed at his iPhone. “I mean, this thing is much faster than those supercomputers,” he told me, laughing. “But with the generation before it would have been impossible to run these codes.”
Nuclear fusion, the reaction that occurs in our sun, has become one of 20th century science’s hottest topics. Its commercial use has remained energetically unviable – that is, a way to produce more energy than is put into a reactor has not been discovered.
Politics has also played its role. From fusion’s theorizing in the 1920s and 30s, governments focuses have rested on fusion as a weapon of war. Ivy Mike, the first bomb using fusion, was exploded by the United States in 1952, with the Cold War ramping up.
For the 7-X team, however, politics has helped, in the form of the Berlin Wall – or rather its fall and Germany’s reunification in 1990. With the Wiedervereinigung came a pledge from the German government to pump funding into the economically weak east. Paul Krüger, then a member of Helmut Kohl’s cabinet as minister of research and technology, was enthused at the prospect of a grand project that could unite the country. He agreed to reignite Wendestein, under one proviso: it would take place in the former east.
Just outside Greifswald sat Lubmin Nuclear Power Station, which has shut shortly before reunification. The town also had a university and a research reputation stretching back centuries. By 1994 the decision was made for Greifswald to be the home of the 7-X. The staff would be 400 strong, the budget would be €550 million ($611 million) and work would be completed in 2007. The future of stellarators had just taken a huge turn for the better.
Almost immediately, things began going wrong. Cooling the magnets, which must operate at almost absolute zero, was a “nightmare,” Klinger admitted. When asked if anything was tougher than the rest, he laughs. “It’s an interesting mix between a science machine, which is very, very much advanced compared to any predecessor – and an industrial project, because all the components were placed within contracts in industry, and correct specifications, drawings, models, you have to work together with industry to solve problems and solve simple delivery milestones.”
When each component is utterly bespoke, the scope for disaster is huge. The 7-X has 70 coils, all of which must be tested for nine weeks. If there is the tiniest of problems, a superconducting coil can switch to a normal conductor. That can be deadly. So some had to be sent via truck from Leipzig, four hours south of Greifswald, nine hours to Paris. They can take two years to disassemble.
One magnet supplier went out of business. One assistant showed me a section of the coil that sits in a display case in the institute foyer. “That nearly sent a company out of business too,” she said.
By 2002 it became apparent the 7-X was never going to be finished by 2007. Project managers revised it up to 2011. “If your completion date moves four years in a couple of months, that’s a strong indicator that something’s wrong,” Klinger said.
The budget had become mayhem, too. Today 7-X has cost Germany just over a billion euros, something for which Klinger, who has led the project since 2007, is hugely grateful: “It shows great vision, and without that we would not be here.”
Last May the machine was finally completed, after 1.1 million man-hours. In December it was switched on. In February this year German premiere Angela Merkel switched on the 7-X for its first full run, heating hydrogen to 80 million degrees for a quarter-second.
The results, Klinger told me, have been encouraging. In 2019 the project will enter its second phase – during which deuterium as well as hydrogen – though even then experts don’t expect to get out more energy than they put in. For now, a goal of 30 minutes sustained power has been targeted.
Safe and usable nuclear fusion energy is the dream of almost everyone on earth, though Klinger stressed that it’s “a long way off yet.” But Wendelstein 7-X is, more than a marvel of engineering, politics and endeavour, a chance to bring that reality closer.
“It has certainly been an incredible journey up until now,” he said.