Problems with fusion ITER means to solve

2007-10-27

in Geek stuff, Science, The environment

Building in Old Montreal

The fundamental problem with nuclear fusion as a mode of energy production is establishing a system that produces more power than it consumes. Heating and containing large volumes of tritium-deuterium plasma is an energy intensive business. As such, the sheer size of the planned International Thermonuclear Experimental Reactor is a big advantage. Just like it is easier to keep a huge cooler full of drinks cold than to keep a single can that way, a larger volume of plasma has less surface area relative to its total energy. As such, bigger reactors have a better chance of producing net power.

The other big problems that scientists and engineers anticipate are as follows:

  1. No previous reactor has sustained fusion for very long. The JT-60 reactors in Japan holds the record, at 24 seconds. Because ITER is meant to operate for between 7 and fifteen minutes, it will produce a higher volume of very hot hydrogen (the product of the tritium-deuterium fusion). That hydrogen could interfere with the fusing plasma. As such, it needs to be removed from the reactor somehow. ITER plans to use a carbon-coated structure called a diverter, at the bottom of the reactor, to try to do this. It is not known how problematic the helium will be, nor how effective the diverter will prove.
  2. Both the diverter and the blanket that surrounds the reactor will need to be able to resist temperatures of 100 million degrees centigrade. They will also need to be able to survive the presence of large amount of radiation. It is uncertain whether the planned beryllium coatings will be adequate to deal with the latter. Prior to ITER’s construction, there are plans to test the planned materials using a specially built particle accelerator at a new facility, probably to be built in Japan. THis test facility could cost about $2.6 billion – one quarter of the total planned cost of ITER itself.
  3. Probably the least significant problem is converting the heat energy from the fusion reaction into electrical power. This is presumably just a matter of putting pipes carrying a fluid into the blanket, then using the expansion of that fluid to drive turbines. While this should be a relatively basic change, it is worth noting that ITER will have no capacity to generate power, and will thus need to dissipate its planned output of about 500 megawatts by other means.

None of these issues undermine the case for building ITER. Indeed, they are the primary justification for building the facility. If we already knew how to deal with these problems, we could proceed directly to building DEMO: the planned electricity-generating demonstration plant that is intended to be ITER’s successor.

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{ 17 comments… read them below or add one }

Litty October 28, 2007 at 12:30 am

Both the diverter and the blanket that surrounds the reactor will need to be able to resist temperatures of 100 million degrees centigrade. They will also need to be able to survive the presence of large amount of radiation.

Will these materials become horribly radioactive?

. July 21, 2008 at 1:53 pm

Helium is only found in useful concentrations in the ‘fossil’ gases emitted by relatively a small number of oil and natural gas wells with especially impermeable caps (in the US, mainly in Texas). The helium was trapped and concentrated there after it was generated by radioactive decay of uranium and thorium in the crust and mantle. Helium is on a depletion curve closely related to that of natural gas (data here and here). In 1996, the US helium reserve was privatised and is now in the process of being sold off (The Impact of the Selling of the Federal Helium Reserve, 2000, Openbook here). Helium production appears to have already peaked in the US. After helium boils out of the huge refrigerated thermos bottles around a superconducting magnet, it escapes into the atmosphere and then diffuses into space, where it is lost forever. Helium is an element and cannot be synthesized. The amount generated by a hypothetical working fusion reactor is negligible. After 20 years of high temperature superconductors, no one has come up with one that is both strong enough and capable of carrying enough current. Such a thing may not exist.

Tokamak-style fusion is predicted to become practical in a few decades. But by then, we may near to past the world peak in helium. Helium demand will soar and helium price will soar, too, but it will be too late. Perhaps it really is true that fusion is the power source of the future, and it always will be, as the joke goes.

. November 18, 2009 at 5:35 pm

Problems related to tritium supply and self-sufficient tritium breeding will be discussed in detail in Section 5.2, but first, it will be useful to describe qualitatively two problems that seem to require simultaneous miracles, if they are to be solved.

“The neutrons produced in the fusion reaction will be emitted essentially isotropically in all directions around the fusion zone. These neutrons must somehow be convinced to escape without further interactions through the first wall surrounding the few 1000 m3 plasma zone. Next, the neutrons have to interact with a “neutron multiplier” material like beryllium in such a manner that the neutron flux is increased without transferring too much energy to the remaining nucleons. The neutrons then must transfer their energy without being absorbed (e.g. by elastic scattering) to some kind of gas or liquid, like high pressure helium gas, within the lithium blanket. This heated gas has to be collected somehow from the gigantic blanket volume and must flow to the outside. This heat can be used as in any existing power plant to power a generator turbine. This liquid should be as hot as possible, in order to achieve reasonable efficiency for electricity production. However, it is known that the lithium blanket temperature cannot be too high. This limits the efficiency to values well below those from today’s nuclear fission reactors, which also do not have a very high efficiency.

Once the heat is extracted and the neutrons are slowed sufficiently, they must make the inelastic interaction with the Li6 isotope, which makes up about 7.5% of the natural lithium. The minimal thickness of the lithium blanket that surrounds the entire plasma zone has been estimated to be at least 1 meter. Unfortunately, lithium like hydrogen (tritium atoms are chemically identical to hydrogen) in its pure form is chemically highly reactive. If used in a chemical bound state with oxygen, for example, the oxygen itself could interact and absorb neutrons, something that must be avoided. In addition, lithium and the produced tritium will react chemically -which is certainly not included in any present computer modeling- and some tritium atoms will be blocked within the blanket. Unfortunately, additional neutron and tritium losses cannot be allowed, as will be described in more detail in Section 5.2.

Next, an efficient way has to be found to extract the tritium quickly, and without loss, from this lithium blanket before it decays. We are talking about a huge blanket here, one that surrounds the few 1000 m3 plasma volume. Extracting and collecting the tritium from this huge lithium blanket will be very tricky indeed, since tritium penetrates thin walls relatively easily, and since accumulations of tritium are highly explosive. An interesting description of some of these difficulties that have already been encountered in a small-scale experiment can be found in reference [38].

Finally assuming we get that far, the extracted and collected tritium and deuterium, which both need to be extremely clean, need to be transported, without losses, back to the reactor zone.

Each of the unsolved problems described above is by itself serious enough to raise doubts about the success of commercial fusion reactors.”

. July 13, 2010 at 10:43 am

EU agrees Iter fusion construction shortfall funds

European Union member states have agreed the additional funds needed to construct Iter (the International Thermonuclear Experimental Reactor).

The French-based machine will prove the concept of harvesting energy from the fusion of hydrogen nuclei – the same process at the heart of the Sun.

Iter has seen its baseline price tag rise dramatically since a consortium of nations green lit the project in 2006.

The extra 1.4bn euros will cover a shortfall in building costs in 2012-13.

After months of protracted negotiations, the monies were finally sanctioned at an Agriculture and Fish Council meeting on 12 July.

. July 26, 2010 at 1:59 pm

Cold fusion is also improbable (at least as an energy source) because it would produce loads of deadly radioactivity. Any scientists near enough to their instruments to get a good reading would almost certainly be fried by radiation. Indeed, one wag has suggested that if a scientist lived long enough to show up for the inevitable press conference announcing his results, that’s almost ipso facto proof that, whatever interesting thing he might have done, he didn’t induce nuclear fusion.”

. April 16, 2012 at 12:12 pm

http://hardware.slashdot.org/story/12/04/11/0435231/mit-fusion-researchers-answer-your-questions

Not to raise any fears — rather out of genuine curiosity — what happens when the magnetic fields that hold the 90,000,000 degrees Celsius plasma in place fail or loser power on the Alcator C-Mod? I understand it’s probably in prototype mode, but what sort of safety advantages or disadvantages do Alcator C-Mod designs offer over conventional, large-scale designs? Does the plasma come into contact with the toroidal superconducting coil? Then what?

Geoff Olynyk answers: Actually, that’s exactly what my research is on! The event you describe is called a “disruption.” Holding a hot plasma stationary using magnetic fields without it ever touching material surfaces is very difficult – Richard Feynman once compared it to trying to “hold Jello with rubber bands.” For any number of reasons, like a magnetic coil losing power, the control system not being able to juggle the plasma position quickly enough, or the plasma hitting a stability limit (pressure or density goes too high), it’s possible for the plasma to hit the wall. The most important thing to know, though, is that when this occurs (and it does, frequently, in today’s experiments – although it’ll have to be a very rare occurrence in a real power reactor so it produces uninterrupted electricity), it is no risk to the environment or to safety.

To understand what happens, you have to realize that the plasma is very, very light. In the Alcator C-Mod tokamak, it has a mass of only about 0.001 grams – about one- fiftieth as much as the smallest drop of water you can get from an eyedropper. (This is with a plasma volume of about a cubic meter – a fusion plasma is actually a pretty good vacuum!) So even though it’s very hot, it doesn’t actually have a lot of thermal stored energy to flow into the wall if confinement is suddenly lost. There is actually more energy stored in the current flowing in the plasma (in C-Mod, about a million amperes), which also gets deposited on the wall. In C-Mod, thermal stored energy is about 50– 150 kJ and magnetic stored energy is almost 1000 kJ. The problem is that as we go to larger machines (like ITER, or a reactor), the amount of stored energy in the plasma scales like the cube of the size, and the wall area only scales like the square of the size. So the energy deposited per square meter of wall area gets worse (larger) as we go up in machine size.

The plasma doesn’t hit the superconducting coils – it hits (really, deposits its energy on) the “first wall” of the chamber closest to the plasma. So, we do two things to make sure that the walls can survive these disruption events. The first is making them out of materials that can take a blast of heat, like tungsten, or else materials that ablate away rather than melting, like carbon fiber composites. The second is to develop “disruption mitigation” systems which can cause the plasma to radiate all its energy evenly over the entire wall surface, spreading the heat out and lessening the chance of causing localized melting. But I want to stress again – disruptions are an operational problem, meaning they might cause a power plant to be offline for a while, but they’re not a safety problem. There is no chance of a runaway reaction or meltdown in a fusion reactor.

. April 16, 2012 at 12:13 pm

We know exactly what we need to do. Not everything has a solution yet – that’s why it’s still a research project! – but we generally know what the big challenges are to get to a working magnetic fusion reactor. Here is a non-exhaustive list:

1 – Non-inductive current drive. We can’t rely on inductors to drive the plasma current since they are inherently pulsed (not steady-state). We think that lower hybrid current drive might be the solution, and are actively researching this on Alcator C-Mod.

2 – Confining a ‘burning plasma.’ This is the big question that ITER will resolve – can we really confine a plasma that is dominantly self-heated – that is, most of its energy comes from fusion reactions rather than external heating. Will new instabilities appear? Or can we confine the plasma as we expect we can.

3 – Confining a steady-state burning plasma while avoiding off-normal events. We have to do both of the previous points at the same time! And we can’t have disruptions too often or else the power plant won’t have a high enough duty factor. The goal is to have disruptions (which require a shutdown) occur less than once per year.

4 – Validated predictive capability for fusion-grade plasmas. We have made great progress in this field already (see our answer to an earlier question), but it’s not at the point yet that, say, fluid mechanics codes are, where Boeing can design an entire plane in the computer before ever building a scale model. We need our models of fusion plasma behavior to be accurate and reliable enough to design first-of-a-kind machines that we are 100% sure will work the way we think they will.

5 – Diagnosing a burning plasma. It’s really hard to tell any of the properties of the plasma even today, when we use pure deuterium fuel (instead of ‘live’ deuterium–tritium fuel), and our plasmas are colder than they would be in a reactor! You can’t, for example, stick a thermometer in to tell the temperature! We have to use subtle effects like bouncing a laser beam off the electrons and telling the temperature from the Doppler shift of the laser from the moving electrons (a technique known as Thomson scattering). Making these diagnostics work in the reactor environment, with higher plasma temperatures and a ferocious flux of neutrons coming out, is a great challenge.

6 – Better understanding of plasma–wall interactions. The plasma is confined by magnetic fields, and ideally doesn’t touch the wall at all, except in a very small area called the divertor. This means that the material challenges in the divertor are severe – we have to figure out a way to operate the plasma so that it’s hot in the center, but cold near the divertor, so that it doesn’t erode the wall too fast. This will be a limiting factor on how long you can run a fusion power plant for before you have to shut it down in order to do maintenance. Ideally, we’d want this to be every 2 years or so, like fission power plants today.

7 – Materials for plasma-facing components. We need to develop new materials that can withstand the high temperatures of the wall of a fusion reactor while resisting neutron damage and not becoming too activated by the neutrons that will pass through them. (There is some progress on this front with ferritic steels and silicon carbide.)

8 – Magnets that meet the plasma physics requirements and allow reactor maintainability at reasonable costs. (Some of us are working on demountable superconducting coil concepts that may eventually be the solution to this!)

9 – Design and materials for tritium fuel cycle and power extraction. Fusion reactors will breed their own tritium fuel from deuterium – this process has to be experimentally tested on a large scale (which will obviously require a burning plasma tokamak).

10 – Reliability, availability, maintainability, and inspectability (RAMI) of the reactor designs. We have to show that our concepts for reactors really are as good as we think they can be.

http://hardware.slashdot.org/story/12/04/11/0435231/mit-fusion-researchers-answer-your-questions

. August 19, 2012 at 5:27 pm

“One of the biggest question marks hanging over the ITER fusion reactor project — a giant international collaboration currently under construction in France — is over what material to use for coating its interior wall. After all, the reactor has to withstand temperatures of 100,000C and an intense particle bombardment. Researchers have now answered that question by refitting the current world’s largest fusion device, the Joint European Torus (JET) near Oxford, U.K., with a lining akin to the one planned for ITER. JET’s new ‘ITER-like wall,’ a combination of tungsten and beryllium, is eroding more slowly (PDF) and retaining less of the fuel than the lining used on earlier fusion reactors, the team reports.”

. March 4, 2014 at 11:07 am

Years from now—maybe in a decade, maybe sooner—if all goes according to plan, the most complex machine ever built will be switched on in an Alpine forest in the South of France. The machine, called the International Thermonuclear Experimental Reactor, or ITER, will stand a hundred feet tall, and it will weigh twenty-three thousand tons—more than twice the weight of the Eiffel Tower. At its core, densely packed high-precision equipment will encase a cavernous vacuum chamber, in which a super-hot cloud of heavy hydrogen will rotate faster than the speed of sound, twisting like a strand of DNA as it circulates. The cloud will be scorched by electric current (a surge so forceful that it will make lightning seem like a tiny arc of static electricity), and bombarded by concentrated waves of radiation. Beams of uncharged particles—the energy in them so great it could vaporize a car in seconds—will pour into the chamber, adding tremendous heat. In this way, the circulating hydrogen will become ionized, and achieve temperatures exceeding two hundred million degrees Celsius—more than ten times as hot as the sun at its blazing core.

. March 4, 2014 at 11:10 am

“Early on, to maintain the schedule, construction was rushed forward, even though significant portions of the tokamak design were incomplete. It was like building the shell of a rocket before its engine is designed—or worse, because, as Chiocchio said, “one of the difficulties with this nuclear building is that after it is built, in many cases, you cannot drill a hole in it. Once a wall is finished, that’s it. The building has a safety function, a confinement function, and one of the main requirements is that it has no cracks through which radioactivity can migrate and escape. We have to be sure that we have not missed anything—every pipe, every cable—because if we do miss something, and someone says, ‘O.K., let’s just bolt this to the wall’—well, no, we cannot do that.” And yet ITER’s tremendous scale and machine density make it virtually impossible to know where everything will go. Six thousand miles of cable will run through the machine, delivering electrical power to two hundred and fifty thousand terminal points. One heating system will send a million watts of microwave radiation through a window made of a large synthetic diamond. The system will require perfectly straight tubular guides to transport the waves; no other component can impede them.”

. March 4, 2014 at 11:28 am

“In the nineteen-eighties, tokamak performance had hit a ceiling because turbulence at the edge of plasmas was impossible to control: electromagnetic eddies carried energy outward from the superhot core in diffuse and unpredictable ways, abrading the tiles on the tokamak walls, sucking impurities into the plasma and cooling it. These instabilities seemed insurmountable until researchers in Germany stumbled upon a discovery: under the right heating conditions, the plasma contained itself by forming a steep, clean pedestal at its perimeter, with its inner temperature and density ballooning. At first, the effect was doubted. There was no theory to explain it, and plasmas had rarely offered gifts, only obstacles. But the pedestal was real, and it was christened H-Mode. It is now ubiquitous in tokamaks, though physicists still have only a general idea how it works, and maintaining it is hard: when the pressure behind the pedestal is too great, the plasma erupts into flares that must be quelled.”

. March 4, 2014 at 11:29 am

“It is unclear whether ITER will have enough power to achieve H-Mode. The relevant heating systems on the largest existing tokamak are the size of five shipping containers; ITER’s will be three times larger, and will have to work in an unproved way, just as pliers the size of a skyscraper cannot be opened by hand. Even if the systems work, there might not be enough of them. Current extrapolations offer only a hazy guide to what ITER will require for the pedestal, with the range of uncertainty—what physicists call the error bar—remaining frustratingly large. Joe Snipes, a physicist at ITER’s headquarters, told me, “We tried and tried and tried—and when I say ‘we’ I mean the entire fusion community, experts from around the world working on different machines—we tried to reduce the error bar, but we really couldn’t do it; the H-Mode depends on so many different factors that we don’t understand.” Some engineers wonder if the relevant heating systems—hardware, costing a billion dollars, first developed for Reagan’s Star Wars Defense Initiative—have outlived their usefulness in tokamaks. Others believe that everything must be tried, because ITER ultimately remains an experiment: mapping the way is its purpose.”

. April 14, 2014 at 7:51 pm

Cost Skyrockets for United States’ Share of ITER Fusion Project

ITER, the international fusion experiment under construction in Cadarache, France, aims to prove that nuclear fusion is a viable power source by creating a “burning plasma” that produces more energy than the machine itself consumes. Although that goal is at least 20 years away, ITER is already burning through money at a prodigious pace. The United States is only a minor partner in the project, which began construction in 2008. But the U.S. contribution to ITER will total $3.9 billion—roughly four times as much as originally estimated—according to a new cost estimate released yesterday. That is about $1.4 billion higher than a 2011 cost estimate, and the numbers are likely to intensify doubts among some members of Congress about continuing the U.S. involvement in the project.

. September 29, 2014 at 6:01 pm

The first of its components arrived at the reactor’s site in Cadarache, in the south of France, earlier this month, just as the foundations were finished. In the next week or so construction should start on the walls that will house its core: the doughnut-shaped vacuum vessel. Perhaps tellingly, no one can say exactly when even that will happen. There has already been a 30-month delay in the manufacture of the vacuum vessel. The most recently published schedule says the first plasma will be created in the vacuum vessel in 2020. That will now have to slip to 2023 or 2024, but the revised official schedule will not be published until mid-2015. The overall cost? Also unknown, but it is sure to surpass by a considerable sum the current official estimate of $20 billion.

http://www.economist.com/news/science-and-technology/21618675-big-nuclear-fusion-project-attempts-move-design

. September 1, 2015 at 1:57 am

In myriad ways, the project is a fragment of the Cold War stranded in the present day. Sakharov had predicted that a reactor based on his sketch would produce energy in only ten or fifteen years. Subsequent physicists who built and ran experimental tokamaks were equally optimistic, always predicting success in a decade or two or three. Yet, while other scientific challenges have been overcome—launching Yuri Gagarin into orbit; delivering a rover to Mars; sequencing the human genome; discovering the Higgs boson in CERN’s Large Hadron Collider—controlled thermonuclear energy has remained elusive. The National Academy of Engineering regards the construction of a commercial thermonuclear reactor—the kind of device that would follow ITER—as one of the top engineering challenges of the twenty-first century. Some in the field believe that a working machine would be a monument to human achievement surpassing the pyramids of Giza.

A sense of crisis has come to surround ITER like the concentric nebulae of a dying sun. The project has been falling behind schedule almost since it began—in 1993, it was thought that the machine could be ready by 2010—and there will certainly be further delays. Morale is through the floor, and one can expect cynicism, disagreements, black humor. “There is anxiety here that it is all going to implode,” one physicist told me. Many engineers and physicists at ITER believe that the delays are self-inflicted, having little to do with engineering or physics and everything to do with the way that ITER is organized and managed. Key members of the technical staff have left; others have taken “stress leave” to recuperate. Not long ago, the director-general, Osamu Motojima, a Japanese physicist, who has run the organization since 2010, ordered workmen to install at the headquarters’ entrance a granite slab proclaiming ITER’s presence. People call it a tombstone.

Early on, to maintain the schedule, construction was rushed forward, even though significant portions of the tokamak design were incomplete. It was like building the shell of a rocket before its engine is designed—or worse, because, as Chiocchio said, “one of the difficulties with this nuclear building is that after it is built, in many cases, you cannot drill a hole in it. Once a wall is finished, that’s it. The building has a safety function, a confinement function, and one of the main requirements is that it has no cracks through which radioactivity can migrate and escape. We have to be sure that we have not missed anything—every pipe, every cable—because if we do miss something, and someone says, ‘O.K., let’s just bolt this to the wall’—well, no, we cannot do that.” And yet ITER’s tremendous scale and machine density make it virtually impossible to know where everything will go. Six thousand miles of cable will run through the machine, delivering electrical power to two hundred and fifty thousand terminal points. One heating system will send a million watts of microwave radiation through a window made of a large synthetic diamond. The system will require perfectly straight tubular guides to transport the waves; no other component can impede them.

ITER is being designed to run its highest-performing plasmas for up to five hundred seconds; but a real reactor would need to work continuously—something that no one has figured out how to do.

“The challenge for the central solenoid is that it has to ramp up every time you do a plasma shot, which is thousands of times during the lifetime of the machine—so you have to create a superconducting cable that can pulse tens of thousands of times without degrading, and that is very hard with niobium-3-tin,” an engineer who worked on the magnet told me. “It is a brittle material. How is it not going to become dust? With each pulse, you are literally breaking it, micro-fracturing it. So what is the solution? Don’t pulse so many times, or pulse with less energy. But you cannot do either. If you pulse with less energy, then you don’t get the heating that you need, and if you pulse fewer times then the life of the machine is shorter. So you are pushing up against the limit of what the material can do.”

“In my opinion, you need very big fusion power to make it viable—two- or three-gigawatt power stations,” he told me.

Assuming that the physics of tokamaks is perfected, and fusioneers can hold a synthetic star indefinitely in a magnetic bottle, someone will still have to solve the tricky problem of how to protect all the machinery that surrounds that bottle. The plasma in a commercial reactor will be a cloud of atom-size H-bombs detonating unceasingly. The tritium fuel is radioactive, but it will not be a source of radioactive waste—it will be transformed into helium. The machine itself will become the waste. Under constant neutron bombardment, nearly all of the tokamak’s crucial parts will become “activated.” Their radioactivity will be low, and will last only about a hundred years—a time frame that scientists tend to believe is manageable—but the structural impact of the neutrons will be awesome.

. June 9, 2016 at 2:49 pm

Compact tokamaks: the approach to bring fusion energy within reach

Fusion reactor development could proceed much more rapidly by scaling down the size of reactors being developed, potentially helping the first compact fusion pilot plants to be ready to produce electricity for the first time within the next decade, writes David Kingham.

The best-performing tokamak in the world is JET, producing 16 MW of fusion power with 24 MW input in 1997 – i.e. 65% as much energy out as was put in. It holds the world record for total fusion power produced and for getting closest to breakeven. To reach this point, fusion research followed a Moore’s law-like path. The temperature, density and energy confinement time, which indicates fusion performance, was increasing at a faster and faster rate up until the JET experiments.

But since then it seems that progress has stalled. There have still been experiments built and much learned, but progress towards energy breakeven has slowed. We still haven’t actually reached energy breakeven almost 20 years after we nearly got there.

Traditional designs have moved to larger dimensions, culminating in the ITER experiment currently under construction in the south of France. This will be over 30m tall and weigh about 23,000 tonnes. The demonstration reactor that follows, dubbed DEMO, will likely be slightly bigger again. When ITER was being designed in the 1990s, it was believed that the only feasible way to increase fusion power was to increase machine size. But the size and complexity of ITER has led to very slow progress in the fusion program, with first fusion set for the mid 2020s. Tired of waiting so long and recognising the inherent difficulties of such a big project, some have been questioning the possibility of a smaller way to fusion.

Tokamak Energy is leading this movement. To date the company has published three papers showing size is not an important factor in fusion reactors and proving that a compact reactor can produce high power. This turns the pursuit of fusion into a series of engineering challenges. The Tokamak Energy plan will overcome these challenges, such as the development of magnets made from high temperature superconductors, delivering a fusion power gain within five years, first electricity within ten years and a 100 MWe power plant within 15 years.

. May 23, 2017 at 2:15 pm

European consortium completes first Iter magnet

The first of 18 toroidal field coils has been made in Europe. Gigantic superconducting magnets, they will generate the magnetic cage to contain the Iter fusion reactor’s plasma.

First Iter plasma chamber tool ready for shipment

The first vacuum vessel sector sub-assembly tool for the Iter fusion reactor has passed factory acceptance tests in South Korea. The tool is by far the largest custom-designed tool for the reactor, currently under construction at Cadarache in southern France.

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