Fusion Power Megathread - always just X number of years in the future!

[KRonn]

Well, it's about time that this tech is perfected! What's been the hold up anyway? How hard could it be!   

[Eddie Teach]

Looks like the University of Washington is also on the fusion train!

Huskies are only good for filming reality shows. 

[Tonitrus]

So what happens if the magnetic containment field fails during one of the reoccurring reactions?  Kiss everything in a 50-mile radius goodbye?

[frunk]

So what happens if the magnetic containment field fails during one of the reoccurring reactions?  Kiss everything in a 50-mile radius goodbye?

The magnetic containment field is so that it can maintain criticality.  If that fails it just means it'll go sub-nuclear very quickly.  It might cause damage in the immediate area but shouldn't go much beyond that.

[jimmy olsen]

A very long, very detailed and very dishearening article on ITER (International Thermonuclear Experimental Reactor).

www.newyorker.com/reporting/2014/03/03/140303fa_fact_khatchadourian?printable=true&currentPage=all

Much more optomistic news can be found here!
http://online.wsj.com/news/articles/SB10001424052702304888404579378920296615030

A Star Is Born: U.S. Scores Fusion-Power Breakthrough
Experimental Reaction Yields Energy, but Sustainability Still Proves Elusive

U.S. scientists replicated the power of the sun, if only for a fleeting moment, creating a miniature star that has rekindled hopes that nuclear fusion could one day offer a source of cheap and boundless energy on Earth.

In experiments done at a U.S. Department of Energy laboratory last fall and published in a scientific journal Wednesday, researchers blasted the world's most powerful laser at a target the size of a small pea. It triggered a fusion reaction that unleashed a vast amount of energy—for a fraction of a second.

"For the first time anywhere, we've gotten more energy out of the fuel than what was put into the fuel" when using this technique, said Omar Hurricane, physicist at the Lawrence Livermore National Laboratory and lead author of the study in the journal Nature.

The research is a long way from achieving what's known as ignition, where the overall setup generates more energy than it consumes in a self-sustaining chain reaction and without which fusion power wouldn't be practical. In the experiments, much of the energy from the laser was dissipated and didn't reach the fuel.

But the latest result marks a step forward for the U.S. project after years of setbacks and false promise. And it offers a concrete model for what a commercially viable nuclear-fusion reactor might look like.

"This experiment suggests that it is possible to get to ignition with the scale" of the laser at the Lawrence Livermore lab, said Steven Cowley, director of the Culham Centre for Fusion Energy in the U.K., who wasn't involved in the study.

Today's nuclear-power plants generate electricity with fission, which involves splitting atoms. In fusion, atomic nuclei are squashed together under intense heat and pressure to release energy.

The power of fusion became known in the 1950s when the first hydrogen bomb was detonated. Harnessing that energy for peaceful purposes has been a lot more difficult—many scientists would use far stronger words—though there are good reasons to keep trying.

Fusion is the most efficient of any known energy-creating process. The fuel is easy to obtain from natural sources, and there are almost no risks of toxic byproducts or nuclear meltdown.

The latest experiment was done at Lawrence Livermore's National Ignition Facility, or NIF. The California facility—a 10-story building the size of three football fields—was built at a cost of $3.5 billion and became operational in 2009. It has since cost hundreds of millions of dollars to operate.

The NIF originally hoped to achieve ignition by September 2013, but didn't come close. Critics have long assailed the NIF for being overbudget, behind schedule and overambitious in its key scientific goal. Even with the latest advance, it is unclear whether it will ever get there.

"It's very hard. We're sort of pushing ourselves to the limit to make this happen," Dr. Hurricane said.

The main rival technique for achieving fusion uses powerful magnets instead of lasers. The U.K.'s Culham Centre used this magnet approach in 1997 to extract 16 megawatts of power by injecting 24 megawatts of power—not too far off from the sought-after "net gain" in energy.

The magnet-based approach has inspired 35 countries, including the U.S., to join forces and embark one of the biggest science projects in recent years: the $20 billion ITER fusion reactor being built in France, which is expected to become operational by 2020.

Most labs have preferred to try the laser approach. The NIF experiment used 192 laser beams and aimed them at a tiny gold can about the size of a dime.

Inside the can was a pea-size capsule containing the fuel, a mixture of two hydrogen isotopes, deuterium and tritium. When laser beams entered the gold can, they struck the inside walls and unleashed a swath of X-rays. Those X-rays smashed into the capsule with tremendous pressure and crushed the fuel capsule to 1/35 of its radial size.

As the capsule shrank, the fuel rapidly converged around the hollow center, but it had nowhere to go. That generated even higher pressures and a temperature higher than what's seen at the center of the sun, triggering fusion.

In essence, the scientists created a miniature star that existed for a fraction of a second—and then blew itself apart.

The energy released was 10 times as great as that achieved in any previous such experiment.

In a striking finding, the data also showed that the nuclear material was self-heating, a crucial condition for ignition.

But ignition remains a long way off. To get there, scientists need to compress the fuel into a nearly perfect spherical implosion, and that's not easy to do. It's one of the reasons past efforts have been fruitless.

"It's like putting your fingers around a balloon and trying to squeeze it until it's a thousand times smaller" without distorting it too much, said Dr. Cowley.

The researchers created about 150 gigabars of pressure in their experiment, and expect that 300 gigabars or more will yield ignition. A gigabar is roughly one billion atmospheres of pressure.

They hope to improve the shape and speed of the implosion. One way, is to alter the shape of the gold container to the shape of a rugby ball.

"Mother Nature doesn't like putting a lot of energy in small volumes, so she fights you on it," Dr. Hurricane said. "This is a way of fighting back."

[Capetan Mihali]

Opened this thread from the beginning and had a disappointment: where's Mongers been hiding out all this time? 

[Siege]

Hey Timmay, you forgot to "Singularity Alert" in the name of this thread.

[jimmy olsen]

Opened this thread from the beginning and had a disappointment: where's Mongers been hiding out all this time? 

Hasn't he always come and gone?

[Eddie Teach]

I'm disappointed Katmai doesn't have more school spirit.

[Tonitrus]

The perpetual motion of fusion progress continues... 

http://www.washington.edu/news/2014/10/08/uw-fusion-reactor-concept-could-be-cheaper-than-coal/

[jimmy olsen]

The perpetual motion of fusion progress continues... 

http://www.washington.edu/news/2014/10/08/uw-fusion-reactor-concept-could-be-cheaper-than-coal/

Looks good, I can't wait to see where this goes.

[jimmy olsen]

Awesome. Lots of start ups working on fusion these days. Makes me hopefully we'll finally have a breakthrough.

http://news.sciencemag.org/physics/2015/06/mystery-company-blazes-trail-fusion-energy

SCIENCE


Mystery company blazes a trail in fusion energy

By
Daniel Clery
2 June 2015 2:30 pm
35 Comments

Of the handful of startup companies trying to achieve fusion energy via nontraditional methods, Tri Alpha Energy Inc. has always been the enigma. Publishing little and with no website, but apparently sitting on a cash pile in the hundreds of millions, the Foothill Ranch, California–based company has been the subject of intense curiosity and speculation. But last month Tri Alpha lifted the veil slightly with two papers revealing that its device, dubbed the colliding beam fusion reactor, has shown a 10-fold improvement in its ability to contain the hot particles needed for fusion over earlier devices at U.S. universities and national labs.

"They've improved things greatly and are moving in a direction that is quite promising," says plasma physicist John Santarius of the Fusion Technology Institute at the University of Wisconsin, Madison.

Fusion energy seeks to replicate the power source of the sun and stars: heating atoms to enormous temperatures so that their nuclei slam together with enough force to overcome their mutual repulsion and fuse, releasing energy. The challenge on Earth is to confine plasma—an ionized gas, with electrons and nuclei separated—at high temperatures (greater than 150 million degrees Celsius) long enough for fusion reactions to occur. Most effort over the past 60 years of fusion research has focused on tokamaks—huge doughnut-shaped vessels that confine plasma with powerful magnets—and laser fusion, which uses high-energy laser pulses to squeeze tiny capsules of fuel. But between these low-density and high-density extremes there is a range of other approaches that have received little government funding. Now, startup companies are moving into that vacuum.

Tri Alpha's device relies on a plasma phenomenon called a field-reversed configuration (FRC), akin to a smoke ring of plasma. Because plasma is made of charged particles (electrons and nuclei), the swirling particles in the FRC create a magnetic field that acts to hold the ring together, potentially long enough for fusion to get going. Tri Alpha's 23-meter-long device has at its heart a long tube with numerous ring-shaped magnets and other devices along its length. It creates a plasma smoke ring close to each end and fires them toward the middle at 250 kilometers per second. At the center they merge, converting their kinetic energy into heat to produce a high-temperature FRC.

In earlier attempts to create long-lived FRCs, turbulence in the plasma caused heat to leak away as hot particles migrated to the edge and escaped, causing the smoke ring to shrink and fade away. And although FRCs proved more stable than other ways of confining plasma, the ring-shaped plasma did tend to tilt or lose shape, causing it hit the tube wall and disintegrate. As a result, researchers couldn't push the lifetime of high-temperature FRCs beyond about 0.3 milliseconds. "They had trouble getting parameters to what was needed," says Santarius, who in the past has worked with Tri Alpha researchers and received funding from the company.

Researchers had theorized that an FRC could be made to live longer by firing high-speed ions into the plasma. Michl Binderbauer, Tri Alpha's chief technology officer, says that once the ions are inside the FRC, its magnetic field curves them into wide orbits that both stiffen the plasma against instability and suppress the turbulence that allows heat to escape. "Adding fast ions does good things for you," says Glen Wurden of the Plasma Physics Group at Los Alamos National Laboratory in New Mexico. Tri Alpha collaborated with Russia's Budker Institute of Nuclear Physics in Akademgorodok, which provided beam sources to test this approach. But they soon learned that "[ion] beams alone don't do the trick. Conditions in the FRC need to be right," Binderbauer says, or the beams can pass straight through. So Tri Alpha developed a technique called "edge biasing": controlling the conditions around the FRC using electrodes at the very ends of the reactor tube.

In papers published last month in Physics of Plasmas and Nature Communications, the Tri Alpha team reveals how fast ions, edge biasing, and other improvements have enabled them to produce FRCs lasting 5 milliseconds, a more than 10-fold improvement in lifetime, and reduced heat loss. "They're employing all known techniques on a big, good-quality plasma," Wurden says. "It shows what you can do with several hundred million dollars." Tri Alpha is supported by "a very diverse group of investors," Binderbauer says, including venture capital companies, billionaire individuals, and the government-owned Russian Nanotechnology Corp.

To achieve fusion gain—more energy out than heating pumped in—researchers will have to make FRCs last for at least a second. Although that feat seems a long way off, Santarius says Tri Alpha has shown a way forward. "If they scale up size, energy confinement should go up," he says. Tri Alpha researchers are already working with an upgraded device, which has differently oriented ion beams and more beam power.

[jimmy olsen]

Woo! With this many different avenues of research one is sure to succeed.

http://gizmodo.com/worlds-most-insane-fusion-reactor-is-about-to-switch-on-1741199892

World's Largest Fusion Reactor is About to Switch On

11/07/15 4:00pm

If "The Stellarator" sounds like an energy source of comic book legend to you, you're not that far off. It's the largest nuclear fusion reactor in the world, and it's set to turn on later this month.

Housed at the Max Planck Institute in Germany, the Wendelstein 7-X (W7-X) stellarator looks more like a psychotic giant's art project than the future of energy. Especially when you compare it with the reactor's symmetrical, donut-shaped cousin, the tokamak. But stellarators and tokamaks work according to similar principles: In both cases, coiled superconductors are used to create a powerful magnetic cage, which serves to contain a gas as it's heated to the ungodly temperatures needed for hydrogen atoms to fuse.

Stellarators are ridiculously hard to build, a fact which should be self-evident after one glance at the W7-X. Its 16 meter-wide ring is bristling with devices and cables of all shapes and sizes, including 250 access ports. The guts of the beast are no less chaotic: Fifty 6-ton magnetic coils, twisted and contorted like clocks in a Dalí. By comparison, the tokamak is an engineer's dream.

But complexity aside, stellarators have certain qualities that make them better suited for commercial applications. Tokamaks can only be turned on for short bursts, and they're prone to magnetic disruptions that can destabilize the entire reactor. As Science News explains in a great long-read on fusion, differences in how the magnetic fields are imposed render stellarators immune to these issues.

It took 19 full years to build W7-X. By the end of the month, approval to turn the reactor on is expected to come from Germany's nuclear regulators. If all goes well and the stellarator is able to hold onto its heat, this crazy device could steer a new course for fusion power. Humanity's energy future: Solar panels, wind turbines, and 300-ton miniature star cores that look like giant katamari. I kinda like it.

And the science

http://www.sciencemag.org/content/350/6259/369.full

Twisted logic

Daniel Clery

If you've heard of fusion energy, you've probably heard of tokamaks. These doughnut-shaped devices are meant to cage ionized gases called plasmas in magnetic fields while heating them to the outlandish temperatures needed for hydrogen nuclei to fuse. Tokamaks are the workhorses of fusion—solid, symmetrical, and relatively straightforward to engineer—but progress with them has been plodding.

Now, tokamaks' rebellious cousin is stepping out of the shadows. In a gleaming research lab in Germany's northeastern corner, researchers are preparing to switch on a fusion device called a stellarator, the largest ever built. The €1 billion machine, known as Wendelstein 7-X (W7-X), appears now as a 16-meter-wide ring of gleaming metal bristling with devices of all shapes and sizes, innumerable cables trailing off to unknown destinations, and technicians tinkering with it here and there. It looks a bit like Han Solo's Millennium Falcon, towed in for repairs after a run-in with the Imperial fleet. Inside are 50 6-tonne magnet coils, strangely twisted as if trampled by an angry giant.

Although stellarators are similar in principle to tokamaks, they have long been dark horses in fusion energy research because tokamaks are better at keeping gas trapped and holding on to the heat needed to keep reactions ticking along. But the Daliesque devices have many attributes that could make them much better prospects for a commercial fusion power plant: Once started, stellarators naturally purr along in a steady state, and they don't spawn the potentially metal-bending magnetic disruptions that plague tokamaks. Unfortunately, they are devilishly hard to build, making them perhaps even more prone to cost overruns and delays than other fusion projects. "No one imagined what it means" to build one, says Thomas Klinger, leader of the German effort.

W7-X could mark a turning point. The machine, housed at a branch of the Max Planck Institute for Plasma Physics (IPP) that Klinger directs, is awaiting regulatory approval for a startup in November. It is the first large-scale example of a new breed of supercomputer-designed stellarators that have had most of their containment problems computed out. If W7-X matches or beats the performance of a similarly sized tokamak, fusion researchers may have to reassess the future course of their field. "Tokamak people are waiting to see what happens. There's an excitement around the world about W7-X," says engineer David Anderson of the University of Wisconsin (UW), Madison.


STELLARATORS FACE THE SAME challenge as all fusion devices: They must heat and hold on to a gas at more than 100 million degrees Celsius—seven times the temperature of the sun's core. Such heat strips electrons from atoms, leaving a plasma of electrons and ions, and it makes the ions travel fast enough to overcome their mutual repulsion and fuse. But it also makes the gas impossible to contain in a normal vessel.

Instead, it is held in a magnetic cage. A current-carrying wire wound around a tube creates a straight magnetic field down the center of the tube that draws the plasma away from the walls. To keep particles from escaping at the ends, many early fusion researchers bent the tube into a doughnut-shaped ring, or torus, creating an endless track.

But the torus shape creates another problem: Because the windings of the wire are closer together inside the hole of the doughnut, the magnetic field is stronger there and weaker toward the doughnut's outer rim. The imbalance causes particles to drift off course and hit the wall. The solution is to add a twist that forces particles through regions of high and low magnetic fields, so the effects of the two cancel each other out.

Stellarators impose the twist from outside. The first stellarator, invented by astrophysicist Lyman Spitzer at Princeton University in 1951, did it by bending the tube into a figure-eight shape. But the lab he set up—the Princeton Plasma Physics Laboratory (PPPL) in New Jersey—switched to a simpler method for later stellarators: winding more coils of wire around a conventional torus tube like stripes on a candy cane to create a twisting magnetic field inside.

In a tokamak, a design invented in the Soviet Union in the 1950s, the twist comes from within. Tokamaks use a setup like an electrical transformer to induce the electrons and ions to flow around the tube as an electric current. This current produces a vertical looping magnetic field that, when added to the field already running the length of the tube, creates the required spiraling field lines.

Both methods work, but the tokamak is better at holding on to a plasma. In part that's because a tokamak's symmetry gives particles smoother paths to follow. In stellarators, Anderson says, "particles see lots of ripples and wiggles" that cause many of them to be lost. As a result, most fusion research since the 1970s has focused on tokamaks—culminating in the huge ITER reactor project in France, a €16 billion international effort to build a tokamak that produces more energy than it consumes, paving the way for commercial power reactors.

But tokamaks have serious drawbacks. A transformer can drive a current in the plasma only in short pulses that would not suit a commercial fusion reactor. Current in the plasma can also falter unexpectedly, resulting in "disruptions": sudden losses of plasma confinement that can unleash magnetic forces powerful enough to damage the reactor. Such problems plague even up-and-coming designs such as the spherical tokamak (Science, 22 May, p. 854).

Stellarators, however, are immune. Their fields come entirely from external coils, which don't need to be pulsed, and there is no plasma current to suffer disruptions. Those two factors have kept some teams pursuing the concept.

The largest working stellarator is the Large Helical Device (LHD) in Toki, Japan, which began operating in 1998. Lyman Spitzer would recognize the design, a variation on the classic stellarator with two helical coils to twist the plasma and other coils to add further control. The LHD holds all major records for stellarator performance, shows good steady-state operation, and is approaching the performance of a similarly sized tokamak.

Two researchers—IPP's Jürgen Nührenberg and Allen Boozer of PPPL (now at Columbia University)—calculated that they could do better with a different design that would confine plasma with a magnetic field of constant strength but changing direction. Such a "quasi-symmetric" field wouldn't be a perfect particle trap, says IPP theorist Per Helander, "but you can get arbitrarily close and get losses to a satisfactory level." In principle, it could make a stellarator perform as well as a tokamak.

The design strategy, known as optimization, involves defining the shape of magnetic field that best confines the plasma, then designing a set of magnets to produce the field. That takes considerable computing power, and supercomputers weren't up to the job until the 1980s.

The first attempt at a partially optimized stellarator, dubbed Wendelstein 7-AS, was built at the IPP branch in Garching near Munich and operated between 1988 and 2002. It broke all stellarator records for machines of its size. Researchers at UW Madison set out to build the first fully optimized device in 1993. The result, a small machine called the Helically Symmetric Experiment (HSX), began operating in 1999. "W7-AS and HSX showed the idea works," says David Gates, head of stellarator physics at PPPL.

That success gave U.S. researchers confidence to try something bigger. PPPL began building the National Compact Stellarator Experiment (NCSX) in 2004 using an optimization strategy different from IPP's. But the difficulty of assembling the intricately shaped parts with millimeter accuracy led to cost hikes and schedule slips. In 2008, with 80% of the major components either built or purchased, the Department of Energy pulled the plug on the project (Science, 30 May 2008, p. 1142). "We flat out underestimated the cost and the schedule," says PPPL's George "Hutch" Neilson, manager of NCSX.

BACK IN GERMANY, the project to build W7-X was well underway. The government of the recently reunified country had given the green light in 1993 and 1994 and decided to establish a new branch institute at Greifswald, in former East Germany, to build the machine. Fifty staff members from IPP moved from Garching to Greifswald, 800 kilometers away, and others made frequent trips between the sites, says Klinger, director of the Greifswald branch. New hires brought staff numbers up to today's 400. W7-X was scheduled to start up in 2006 at a cost of .550 million.

But just like the ill-fated American NCSX, W7-X soon ran into problems. The machine has 425 tonnes of superconducting magnets and support structure that must be chilled close to absolute zero. Cooling the magnets with liquid helium is "hell on Earth," Klinger says. "All cold components must work, leaks are not possible, and access is poor" because of the twisted magnets. Among the weirdly shaped magnets, engineers must squeeze more than 250 ports to supply and remove fuel, heat the plasma, and give access for diagnostic instruments. Everything needs extremely complex 3D modeling. "It can only be done on computer," Klinger says. "You can't adapt anything on site."

By 2003, W7-X was in trouble. About a third of the magnets produced by industry failed in tests and had to be sent back. The forces acting on the reactor structure turned out to be greater than the team had calculated. "It would have broken apart," Klinger says. So construction of some major components had to be halted for redesigning. One magnet supplier went bankrupt. The years 2003 to 2007 were a "crisis time," Klinger says, and the project was "close to cancellation." But civil servants in the research ministry fought hard for the project; finally, the minister allowed it to go ahead with a cost ceiling of .1.06 billion and first plasma scheduled for 2015.

After 1.1 million construction hours, the Greifswald institute finished the machine in May 2014 and spent the past year carrying out commissioning checks, which W7-X passed without a hitch. Tests with electron beams show that the magnetic field in the still-empty reactor is the right shape. "Everything looks, to an extremely high accuracy, exactly as it should," IPP's Thomas Sunn Pedersen says.

Approval to go ahead is expected from Germany's nuclear regulators by the end of this month. The real test will come once W7-X is full of plasma and researchers finally see how it holds on to heat. The key measure is energy confinement time, the rate at which the plasma loses energy to the environment. "The world's waiting to see if we get the confinement time and then hold it for a long pulse," PPPL's Gates says.

Success could mean a course change for fusion. The next step after ITER is a yet-to-be-designed prototype power plant called DEMO. Most experts have assumed it would be some sort of tokamak, but now some are starting to speculate about a stellarator. "People are already talking about it," Gates says. "It depends how good the results are. If the results are positive, there'll be a lot of excitement."

[jimmy olsen]

Fusion power! Now "only six years away!"

https://www.newscientist.com/article/dn25581-complex-fusion-reactor-takes-shape-as-start-date-slips?full=true#.U4zR72eKDmg

Complex fusion reactor takes shape as start date slips

By Sumit Paul-Choudhury in La Seyne-sur-Mer, France

ITER is a massively complex project, both technically and logistically

Nobody said it was going to be easy. After years of delays, work has finally begun on key components of ITER, the ambitious international project to build a revolutionary nuclear fusion reactor. ITER remains dogged by its own complexity, however, and its director-general says that it may not now fire up until 2023 – three years later than the most recent official deadline.

ITER's ultimate aim is to generate energy in the same way that the sun does, by fusing hydrogen nuclei to form helium. It will do this by using a magnetic field to confine a superheated hydrogen plasma inside a doughnut-shaped reactor called a tokamak.

A collaboration between China, Russia, India, Japan Korea, the US and the EU, ITER's reactor will be larger and far more intricate than any previous tokamak. It will have as many as 10 million parts – its builders call it the puzzle with 10 million pieces – and will sit at the centre of a vast support system. The result will rival the Large Hadron Collider for the title of most complex machine on earth.

Progress on ITER has been slow – it was first conceived during diplomatic talks between US president Ronald Reagan and Soviet leader Mikhail Gorbachev in 1985. Now, at last, the pieces of the puzzle are falling into place, although most of the ITER site, at Cadarache in southern France, is still barren. That is because the real action is taking place elsewhere.

Sun, sea and steel

The French Riviera is more generally associated with sun and sea than with mega engineering projects. When I visit the facility in La Seyne-sur-Mer where some of ITER's biggest components are being prepared, a fierce mistral is blowing off the land to the Mediterranean. CNIM, the contractor that owns the facility, started out as a shipbuilder before turning to precision engineering. Its maritime location is an advantage: many of ITER's components are so heavy that they have to be transported by sea.

In one of the facility's climate-controlled warehouses, a huge drill is carving channels into a D-shaped loop of high-grade stainless steel- so large that it takes me nearly a minute to walk its circumference. The steel, chosen for its strength at low temperatures, is so tough that the carbide bits milling it must be replaced every eight minutes. It needs to be: seven of these loops will be stacked on top of each other to form one of the many magnets that will confine and direct hydrogen plasma at up to 100 million °C in the reactor vessel.

Before that, though, a complicated journey lies ahead. The loops' next stop will be La Spezia, Italy, where a contractor will fit up to 700 metres of superconducting cable to each one; then they will travel to Venice, where another firm, Simic, will complete their assembly into structures called toroidal field coils, each weighing about the same as a fully laden Boeing 747. Simic is also milling some of the loops, so those will have to make a round trip to La Spezia and back.

The coils will then voyage to a French port, where they will be loaded onto a 800-tonne, 352-wheeled crawler that inches through 104 kilometres of countryside, crossing specially strengthened bridges and squeezing through carefully widened roads, to Cadarache. If all goes to plan, the first coils will arrive at the ITER site in about three years' time.

Deadline implausible

Still, progress on the toroidal coils seems faster than on the second of the reactor's key magnetic arrays, the so-called poloidal field coils. The building specially built for their construction is impressively large but mostly empty, save for half a dozen crates and a circular crane that hangs from the roof like a vast yellow spider, as it has been since 2012 when New Scientist last visited.

Following mounting criticism of ITER's progress, director-general Osamu Motojima is striving to put the monumental project on "a more realistic schedule". He told New Scientist that the difficulty of integrating the parts supplied by ITER's myriad partners made the current deadline of 2020 for "first plasma" implausible; 2022 or 2023 are more likely.

Even once first plasma has been achieved, the reactor will spend years running experimentally before switching to the deuterium-tritium mix needed to generate substantial power. Motojima hopes this second milestone, scheduled for 2027, will still be achievable.

All this is taking its toll on morale. Several of the senior ITER figures I spoke to felt that ITER's politics – with member states jostling for contracts, and supposedly identical parts often made by different manufacturers on different continents – together with the technical challenges, made even Motojima's revised timeframe unworkable. They are quietly banking on 2025 or beyond. "I hope I see first plasma while I'm still on the project," says Neil Mitchell, head of ITER's magnets division.

Others are enjoying the ride. "ITER is not the first mega project: it's a great challenge, but it's also great fun," says Ken Blackler, who will have the job of fitting together the giant components inside the tightly confined wall of the reactor, Tetris-style.

The most impassioned advocate I hear from is Mark Henderson, who runs the microwave system that will help heat the plasma. He argues forcefully that fusion is the only adequate response to climate change. "Grasping the sun and bringing it to earth is greater than going to the moon and decoding DNA," he says. But he too agrees that the rate of development needs to accelerate, and the road to practical fusion power may be a long one.

Those working on ITER today may have to live in the knowledge that the fruit of their labours will be reaped by others.

The writer's accommodation, meals and travel within France were provided by Fusion For Energy

[jimmy olsen]

Looking good. 

http://www.sciencealert.com/tests-confirm-that-germany-s-massive-nuclear-fusion-machine-really-works

Tests Confirm That Germany's Massive Nuclear Fusion Machine Really Works

Harnessing the power of the Sun.

FIONA MACDONALD

6 DEC 2016

Germany switched on a new type of massive nuclear fusion reactor for the first time, and it was successfully able to contain a scorching hot blob of helium plasma.

But since then, there's been a big question - is the device working the way it's supposed to? That's pretty crucial when you're talking about a machine that could potentially maintain controlled nuclear fusion reactions one day, and thankfully, the answer is yes.

A team of researchers from the US and Germany have now confirmed that the Wendelstein 7-X (W 7-X) stellerator is producing the super-strong, twisty, 3D magnetic fields that its design predicted, with "unprecedented accuracy". The researchers found an error rate less than one in 100,000.

"To our knowledge, this is an unprecedented accuracy, both in terms of the as-built engineering of a fusion device, as well as in the measurement of magnetic topology," the researchers write in Nature Communications.

That might not sound exciting, but it's crucial, because that magnetic field is the only thing that will trap hot balls of plasma long enough for nuclear fusion to occur.

Nuclear fusion is one of the most promising sources of clean energy out there - with little more than salt water, it offers limitless energy using the same reaction that powers our Sun.

Unlike nuclear fission, which is achieved by our current nuclear plants, and involves splitting the nucleus of an atom into smaller neutrons and nuclei, nuclear fusion generates huge amounts of energy when atoms are fused together at incredibly high temperatures. And it produces no radioactive waste or other byproducts.

Based on the longevity of our Sun, nuclear fusion also has the potential to supply humanity with energy for as long as we need it - if we can figure out how to harness the reaction, that is.

And that's a pretty big 'if', because scientists have been working on the problem for more than 60 years, and we're still a fair way off our goal.

The main challenge is that, in order to achieve controlled nuclear fusion, we have to actually recreate conditions inside the Sun. That means building a machine that's capable of producing and controlling a 100-million-degree-Celsius (180 million degree Fahrenheit) ball of plasma gas.

As you can imagine, that's easier said than done. But there are several nuclear fusion reactor designs in operation around the world right now that are trying their best, and the W 7-X is one of the most promising attemps.

Instead of trying to control plasma with just a 2D magnetic field, which is the approach used by the more common tokamak reactors, the stellerator works by generating twisted, 3D magnetic fields.

This allows stellerators to control plasma without the need for any electrical current - which tokamaks rely on - and as a result, it makes stellerators more stable, because they can keep going even if the internal current is interrupted.

Well, that was the idea of its design, at least.

Despite the fact that the machine successfully controlled helium plasma in December last year, and then the more challenging hydrogen plasma in February, no one had shown that the magnetic field was actually working as it should be.

To measure it, a team of researchers from the US Department of Energy and the Max Planck Institute of Plasma Physics in Germany sent an electron beam along the magnetic field lines in the reactor.

Using a fluorescent rod, they swept through those lines and created light in the shape of the fields. The result, which you can see in the image above, shows the exact type of twisted magnetic fields that it was supposed to make.

"We've confirmed that the magnetic cage that we've built works as designed," said one of the lead researchers, Sam Lazerson from the US Department of Energy's Princeton Plasma Physics Laboratory.

Despite this success, W 7-X isn't actually intended to generate electricity from nuclear fusion - it's simply a proof of concept to show that it could work.

In 2019, the reactor will begin to use deuterium instead of hydrogen to produce actual fusion reactions inside the machine, but it won't be capable of generating more energy than it current requires to run.

That's something that the next-generation of stellerators will hopefully overcome. "The task has just started," explain the researchers in a press release.

It's not something that will happen tomorrow, but it's an incredibly exciting time for nuclear fusion, with W 7-X officially competing with France's ITER tokamak reactor - both of which have been able to trap plasma for long enough for fusion to occur.

The real question now is, which of these machines will be the first to bring us efficient power from nuclear fusion? We can't wait to find out.