Nuclear fusion – a process which some scientists claim could safely power the world without producing radioactive waste – has remained elusive since work began on it in the 1920s. But now it’s a step closer to reality, as researchers attempt to recreate the power of the Sun by building a star on Earth.
Dozens of scientific projects have fought to make commercial nuclear fusion a reality. None has succeeded. But in 2021, an ambitious European-funded project in the UK will switch on for the first time in 23 years, and it could be a vital step on the road to fusion.
Inside a reactor shaped like a giant doughnut, scientists from the Joint European Torus (or JET) project will smash hydrogen atoms together at high speed, releasing a huge amount of energy and heat in the form of plasma. Temperatures will reach a level ten times hotter than the Sun as the plasma swirls around.
The experiment is paving the way for ITER, a bigger nuclear fusion reactor project based in the south of France and funded by 35 countries, which will demonstrate fusion on the scale of commercial power production, yielding almost limitless amounts of energy in the process. That huge project, which will be unveiled in 2025, is relying on JET’s experiments to cut down the amount of time required to take fusion power out of the lab and into our homes. Natasha Bernal
The exterior of Europe’s JET tokamak at Culham, a doughnut-shaped magnetic confinement device for fusion energy. At JET, European scientists smash hydrogen atoms together in a hot plasma at high speed, releasing a huge amount of energy.
These colourful pipes are called waveguides, and they are used to transmit microwaves into the plasma — an ionised state of matter similar to a gas — to help heat it up to temperatures ten times hotter than the Sun.
A set of robotic arms, operated remotely by engineers in a control room, practices moving items inside the replica tokamak test facility without touching its valuable metal wall. This replica tokamak is just 50m away from the real JET machine. Robots are being used to carry out upgrades and repairs within the tokamak, which will be mildly radioactive during and after the fusion tests.
One of the stations in JET’s control room, where European scientists perform plasma tests almost every 30 minutes during the day and night ahead of the tritium tests later this year. The control panels feature a direct phone line to National Grid to make sure that the enormous use of energy for the tests does not overload the grid at key times when there is high demand, such as during the Champions League final.
Inside this room, engineers train for years to flawlessly control robot arms, which mirror the movements of identical ones within the tokamak. This robot is called MASCOT – it mimics human arms and hands, and is capable of tightening screws and “feeling” objects on behalf of humans that control it from a safe distance. Robots go into the tokamak when human beings cannot, to make repairs and move things around when the radioactive environment would make it impossible for humans to access the space.
Another view of the JET machine, showing the long transmission lines of another wave heating system that will be used to control the temperature of the experiment.
Natasha Bernal is WIRED’s business editor. She tweets from @TashaBernal
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