Energy

Building to house world's largest tokamak fusion reactor now complete

Building to house world's larg...
Inside the building that will house the world's largest tokamak reactor
Inside the building that will house the world's largest tokamak reactor
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The site of ITER in France
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The site of ITER in France
Bird's eye view of the ITER construction site
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Bird's eye view of the ITER construction site
ITER will play host to streams of plasma 10 times thicker than the largest tokamak in action today
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ITER will play host to streams of plasma 10 times thicker than the largest tokamak in action today
Inside the building that will house the world's largest tokamak reactor
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Inside the building that will house the world's largest tokamak reactor

The structure that will house one of the largest and most ambitious energy experiments in history is now complete, with engineers working on the ITER Tokamak Building swinging their last pylon into place in readiness for the nuclear fusion reactor's assembly stage. Nine years in the making, the facility is built to host the type of super-hot high-speed reactions that take place inside the Sun, and hopefully advance our decades-long pursuit of clean and inexhaustible nuclear fusion energy.

In the works since 1985, ITER (International Thermonuclear Experimental Reactor) is a type of nuclear fusion reactor known as a tokamak and is a collaborative project involving thousands of scientists and engineers from 35 countries. These donut-shaped devices are designed to accommodate circular streams of plasma consisting of hydrogen atoms, which are compressed using superconducting magnets so that they fuse together and release monumental amounts of energy.

There are key technological challenges to overcome when it comes to tokamak reactors. Chiefly, these center on bringing them up to the required temperatures and keeping the streams of plasma in place long enough for the reactions to take place.

ITER will play host to streams of plasma 10 times thicker than the largest tokamak in action today
ITER will play host to streams of plasma 10 times thicker than the largest tokamak in action today

A number of experimental tokamak devices are in operation around the world and continue to make strides toward the goal of practical nuclear fusion power generation. These include UK firm Tokamak Energy’s device, which last year hit temperatures of 15 million degrees Celsius, and China’s Experimental Advanced Superconducting Tokamak, which in 2016 maintained superheated plasma for a record 102 seconds and last year hit internal temperatures of 100 million degrees Celsius.

None will reach the heights of ITER, however, both figuratively and literally. Vinci is the construction firm behind the Tokamak Building and has just put the finishing touches on the 73-meter-tall (240-ft) structure that will house the largest tokamak reactor on the planet.

ITER will play host to streams of plasma 10 times thicker than the largest tokamak in action today. The premise for building such a large version of an experimental device is quite straightforward – the larger and longer the plasma streams, the greater opportunity there is for nuclear fusion reactions to take place.

The site of ITER in France
The site of ITER in France

The most power a tokamak reactor has ever put out is 16 MW, a record achieved in 1997 by the UK’s Joint European Torus tokamak. The team behind ITER has set its sights on 500 MW. With construction now complete on the building, workers will soon begin putting together the millions of parts making up the reactor.

This assembly phase is expected to take five years, with the team hoping to achieve first plasma in 2025.

Sources: Vinci, ITER

16 comments
Bob Stuart
As usual, the goal is cheap, clean power, but the dirty reality is that this only runs on radioactive hydrogen and frees the neutrons for their usual long-term mischief. The windmills have won the market, turning this into high-tech welfare.
Brian M
@Bob Stuart - By 'radioactive Hydrogen' I presume you mean Tritium which is a simple isotope, of hydrogen. With two neutrons where regular hydrogen does not have any, which makes tritium unstable and therefore radioactive giving off beta radiation. But despite 'being radioactive' its nowhere similar to plutonium as a health risk. Its actually used in commercial products such as glow in the dark emergency exit signs etc where no electricity is required. Whether Tokamac fusion reactors or similar will ever work as a source of energy is a question. But the benefits if they did are so huge its certainly worth the final cost. Fusion technology is nuclear energy without the bad byproducts.
michael_dowling
@Brian M: No,fusion is very unlikely to be economical in operation,and will suffer large parasitic power demands that will make all but the largest reactors unfeasible to run economically. Also,a fusion reactor's components will face annual expenses for replacing highly radioactive core components. A retired plasma physicist has written a rather depressing article on the problems facing magnetic confinement type fusion reactors: https://thebulletin.org/2017/04/fusion-reactors-not-what-theyre-cracked-up-to-be/
Brian M
@michael_dowling I don't know whether fusion technology will work, but being still at the research stage means its way too early to write it off. The research is also leading to other understandings in physics and engineering, so even if nothing comes of it, its still adds to our knowledge - never a bad thing! The 'green' technologies we currently have are not without their own issues - for example wind turbines are not 24hours, same with solar. There are possible issues with sourcing the rare metals etc for the construction, same with electric cars. Everything has downsides and unintended consequences, that's why we need as many options and spread of technology as possible. Fusion with 24 hour availability just needs to be part of the ongoing research to secure new technologies.
bwana4swahili
@Bob Stuart - "windmills have won the market" If so, why is Germany questioning their whole approach to wind energy and its sporadic nature, health issues, cost, etc. Wind will NEVER be the solution to gobal energy requirements!!
Douglas Rogers
No one has mentioned high temperature superconductors. A group at MIT says they can redesign ITER at 1/3 the size so it is buildable by large institutions and mid sized nations. They claim the economics are quite favorable and a ten tear development time.
Ben Roberts
Has any Tokamak reactor ever created a sustained fusion reaction? I don't think it has. Just making a bigger one won't make it work any better!
Matthew Harrison
Would have been nice to say where in France it is.
Charles Myers
I see we have a somewhat limited scope of responses. Did it ever occur to some that there is more than one way to do this? Lockheed Martin and their 5th generation 'compact fusion reactor' is underway. Go ahead, go 'Google' it! I've studied what limited information Lockheed has released and it quickly occured to me that Lockheed isn't using magnetic fields to contain a large 'cloud' of fusing plasma. Lockheed is pre heating the hydrogen isotopes of tritium and deuterium to a plasma state and then stripping the electrons away from the nuclei. Lockheed then directs the streams of nuclei via some sort of 'injection' mechanism towards the center of an open chamber where they also direct the free electrons. They come together at a single point within the chamber with enough force to fuse. Magnetic containment is relatively unneeded as this reaction forms in a very small point in the chamber and rapidly dissipates into a more useful heat energy. Neutron containment is probably with a combination of a Beryllium outer shell and a composite of silcon firebricks containing Boron 10 which absorbs neutrons and becomes Boron 11 over time neither of which are 'radioactive' in any way. The tritium for the reaction could probably be produced by focusing a portion of those neutrons on the deuterium isotope which is readily available in common tap water or most certainly water from the bottem of a deep reservoir. The ITAR is a large 'global' boondoggle of an infinitely stupid expense based on an antiquated concept from the 1950s Soviet Union. The Lockheed Martin compact fusion reactor is expected to fit on the back of a semi tractor trailer truck and have a net production of approximately 80,000 kW. There is even suggestion that it could easily power aircraft. True genius NEVER follows conventional wisdom and when Lockheed Martin is involved with their own money and on their 5th generation prototype, something informs me that they are setting the final output and safety parameters. Go ahead all of you....please, by all means, look it up! We're expecting a working mass produce capable reactor within the next 3 years. Enjoy the 10s of billions of squandered dollars or Euros on ITAR. I have my popcorn ready for this spectacle.
Chris
This is pure speculation, but it seems to me that isotopic hydrogen is only required because it is easier to fuse due to its inhernet instability. I'm reminded, however, of thermonuclear weapons, which use a starter fission reaction to achieve the required conditions for a fusion reaction. Could dirty fusion be used similarly to generate sustainable conditions for a pure hydrogen fusion reactor?