Energy

Wendelstein 7-X fusion reactor keeps its cool en route to record-breaking results

Wendelstein 7-X fusion reactor...
Inside the contorted chamber of the Wendelstein 7-X nuclear reactor
Inside the contorted chamber of the Wendelstein 7-X nuclear reactor
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Inside the contorted chamber of the Wendelstein 7-X nuclear reactor
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Inside the contorted chamber of the Wendelstein 7-X nuclear reactor
Record-breaking hydrogen plasma has been produced inside the Wendelstein 7-X fusion reactor
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Record-breaking hydrogen plasma has been produced inside the Wendelstein 7-X fusion reactor
Though more than a million assembly hours went into the initial construction of the Wendelstein 7-X, the stellarator remains a constant work in progress
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Though more than a million assembly hours went into the initial construction of the Wendelstein 7-X, the stellarator remains a constant work in progress

Scientists toiling away on the cutting edge Wendelstein 7-X nuclear fusion reactor in Germany have pulled together results from their latest round of testing, with a few records to be found amongst them. Following a series of upgrades, the team is reporting the experimental device has achieved its highest energy density and the longest plasma discharge times for device of this type, marking another step forward in the quest for clean fusion power.

Can something like the Wendelstein 7-X someday be used as part of a zero-emission power plant? Like other experimental nuclear fusion reactors, it is designed to recreate the reaction that takes place in stars, just like our own Sun. The idea is to use magnetic fields to suspend a heated stream of plasma long enough for atomic nuclei within it to fuse together, releasing tremendous amounts of energy in the process.

But holding a stream of plasma in place with magnetic fields isn't easy, especially when it needs to reach temperatures hotter than the Sun. For some time, scientists pursued this through what are known as tokamak fusion reactors, simpler devices built to suspend the plasma stream inside a chamber in nicely rounded doughnut-like shape.

By contrast, Wendelstein 7-X is what is known as a stellarator nuclear reactor. Rather than a clean doughnut shape, it takes a highly complex form using 50 superconductive magnetic coils to hold plasma inside a containment field that twists and turns through an irregular loop. It is hoped this approach can prevent the plasma streams drifting into the outer walls of the reactor and collapsing.

Though the idea of a stellarator first bobbed up at Princeton way back in 1951, the calculations they require were seen as too complex to realistically entertain until the arrival of the supercomputer. Even then the Wendelstein 7-X took 15 years to put together, but the result is the largest and most sophisticated stellarator device the world has ever seen.

Scientists at the Max Planck Institute for Plasma Physics first fired it up in December 2015, and have made regular strides forward since then. That initial flash of helium plasma lasting one tenth of a second was followed up months later with the first burst of hydrogen plasma, lasting all of a quarter of a second.

Record-breaking hydrogen plasma has been produced inside the Wendelstein 7-X fusion reactor
Record-breaking hydrogen plasma has been produced inside the Wendelstein 7-X fusion reactor

Now the team says its latest round of experiments have achieved long-lasting plasmas of more than 100 seconds for the first time, a record for this kind of stellarator. What's more, they are also reporting unprecedented energy yields, brought on by newly installed components that inject fast hydrogen atoms into the plasma stream.

This resulted in high plasma densities of 2 x 1020 particles per cubic meter, which according to the scientists, are values sufficient for a future power station. The energy content of the plasma exceeded 1 megajoule for the first time ever, without the vessel walls becoming too hot. The plasma temperature, meanwhile, hit 20 million °C (36 million °F), exceeding the Sun's temperature of 15 million °C ( 27 million °F).

"Congratulations to the Wendelstein 7-X team on the new world record," said Germany's Federal Research Minister, Anja Karliczek. "The approach is the right one – in this way, important new findings have been made for the future use of fusion power stations. Alongside renewables, fusion energy could be the energy source of the future. The researchers in Greifswald have taken an important step in this direction with their work. I wish the team every success with their future work."

Though more than a million assembly hours went into the initial construction of the Wendelstein 7-X, the stellarator remains a constant work in progress
Though more than a million assembly hours went into the initial construction of the Wendelstein 7-X, the stellarator remains a constant work in progress

Though more than a million assembly hours went into the initial construction of the Wendelstein 7-X, the stellarator remains a constant work in progress. In September 2017, the interior walls of the container were fitted with graphite tiles, allowing for higher internal temperatures and longer plasma discharges. Though these proved pivotal in the team's latest success, they are already due to be replaced with water-cooled elements made from carbon fiber.

This will help the team work toward its aims of continuously containing super-hot plasma in the Wendelstein 7-X's contorted magnetic fields for more than 30 minutes at a time. Though the device is not actually designed to produce energy, if it can be achieved, this highly elaborate proof-of-concept device would provide compelling evidence that stellarators, and nuclear fusion, can form part of an environmentally sustainable energy mix. Though, for now, that still remains a big if.

Source: Max Planck Institute for Plasma Physics

15 comments
VincentWolf
It's still 50 to 100 years off a commercial fusion power plant.
David Antoni
More like 5-10 years before we see one.
jeff15
Vincent, it was 30 years in the future when I was a teenager ( now in my 70s), I hope to see the estimate coming down before I'm pushing up daisies!
Mzungu_Mkubwa
I feel like this won't see functional success until it is scaled down. Just like many aircraft designs don't scale up well, it seems like they're building this too big (I'm sure for very practical reasons.) Until the tech is in place to miniaturize this appropriately, it seems as if the economies of scale are preventing crossing the threshold into energy generation. (Hmmm... I wonder if Zemeckis has the brand "Mr. Fusion" trademarked...)
guzmanchinky
Yes, I'm sure all these fusion reactors built for billions are just a farce, 50 years at least. C'mon people, science is advancing EXPONENTIALLY compared to even 10 years ago. Humans can't seem to grasp how fundamentally our world is going to change in the next two decades, even though it has changed fundamentally in the last two...
The Bishop of D
There isn't enough information in the article to provide any reasonable basis for estimating when stable break-even conditions will be achieved, much less positive output. Conspicuously missing from the article is any indication of how close the German team is to attaining the Lawson criteria. Controlled fusion in something smaller than a star has been 5 years away since the early 1970's. Plus ça change, plus c'est la meme chose.
PeakSpecies
This was pretty much a promotional article with no attempt to look into the criticisms of this technology. The history of this fusion energy quest goes back a half-century. The achievement of a practical fusion energy plant has always been claimed to be just a decade, or two, away. Most of the people now working in this field have little understanding of the string of failures of the past. The article starts by claiming such power production will involve 'zero-emission power plants.' The generation of the construction materials tend to not be zero CO2 emissions, especially for the generation of cement. No mention, was made in this article, of the necessity to use radioactive tritium which can be difficult to contain. The article didn't mention that temperatures of around 100 million Kelvin will need to be achieved and maintained. From the dense plasma an intense flux of fusion energy neutrons will be emitted in all directions. That will be in very close proximity to the superconducting plasma confinement magnets that must be maintained at very close to zero Kelvin. The construction materials are limited to those that will not be transmuted into other isotopes by the intense neutron flux. These articles are aimed at folks who do not have the technical backgrounds needed to think critically about such issues. The source information, for the writers, is aimed more at attracting continuing financial support. Those, who believe that we have 20 years to develop this technology, typically have not been closely following the predictions of those studying abrupt climate change effects. By the year 2040 industrial civilization will have collapsed and humans may have gone extinct.
Douglas Bennett Rogers
ITER and, possibly, it's Chinese cousin are the only fusion machines under construction that meet all of the fusion criteria. ITER is designed to have Q of 1.1, which means it will have a power gain of 10 %. It will run about a half hour a day and heat a small lake. If the collected data proves favorable after several years DEMO will be built. This will be the result of the data and have steam turbines and be grid connected.
bwana4swahili
Wow, a whole 100 seconds of operation! 30 minutes in 25-30 years. Commercial power in what... 100++ years? I've been hearing about fusion energy since I was in university 60 years ago, still spending billions and no commercial results. Not holding my breath on this boondoggle!!
guzmanchinky
The level of pessimistic and conspiratorial ignorance astonishes me. This is inevitable technology, and with how quickly supercomputers are chewing on this problem you will see it rise very quickly. The people who say "we've been trying this for ages" have zero concept as to the nature of technological advancement feeding itself. That is to say, we have computers now creating computers, interconnected systems of scientific breakthroughs instantly implemented across disciplines and countries. This has never happened before, and will propel us into an age of limitless clean power much sooner than anyone expects.