Researchers at the Max Planck Institute for Plasma Physics in Germany announced on Thursday that they successfully tested a new nuclear fusion device, dubbed the Wendelstein 7-X (W7-X), and took a step towards achieving the dream of a limitless supply of clean energy through nuclear fusion. The machine, a new type of nuclear fusion device called a stellarator, could help solve the planet’s energy problems and render fossil fuels obsolete.
German scientists successfully used the 16-meter Wendelstein 7-X machine to heat one milligram of helium gas to one million degrees Celsius for only one-tenth of a second.
Wendelstein 7-X, built at a cost of about $1.1 billion, is a “proof-of-concept” prototype designed and built to test the idea behind a new type of nuclear fusion machine, called a “stellarator,” that recreates conditions similar to those obtained inside stars — such as our Sun — by generating superheated plasma required to initiate nuclear fusion reactions.
Nuclear fusion occurs when two or more atomic nuclei fuse and release huge amounts of energy in the process. The reaction occurs only at very high temperatures, obtained in stars such as our Sun, which has been running as a nuclear fusion reactor for more than 4.5 billion years.
Scientists hope to be able to recreate conditions inside our Sun by using a nuclear fusion device, such as a “stellarator,” which heats hydrogen or helium gas to millions of degrees Celsius.
— MPI für Plasmaphysik (@PlasmaphysikIPP) December 10, 2015
Scientists are excited about the prospects of nuclear fusion as a source of energy because it has the potential to generate huge amounts of energy. Today’s nuclear reactors are based on nuclear fission, which involves splitting atomic nuclei to release energy. Nuclear fusion is more environmentally friendly because, unlike nuclear fission, it does not generate hazardous radioactive waste. The development of effective nuclear fusion reactors that need only saltwater to run would help to provide clean energy and end reliance on fossil fuels.
However, a major technical difficulty scientists and engineers working to develop viable nuclear fusion reactors have faced is designing and building a device that can generate and hold plasma heated to 100 million degrees Celsius. A sealed container is needed to hold the plasma, and the plasma must not touch the sides of the container, otherwise it would melt the material.
Previously used fusion containers called tokamaks are doughnut-shaped fusion reactors, equipped with superconducting magnets and powerful currents that generate a magnetic field that is able to confine plasma in the shape of a torus (roughly “doughnut-shape”).
But tokamak reactors could only control or maintain plasma for about 6 minutes and 30 seconds, not long enough to harvest the energy. They also suffered the disadvantage of consuming more energy than generated from nuclear fusion.
The stellarator design is an alternative design that scientists hope will help to overcome the limitations of the tokamak design and eventually control plasma for up to 30 minutes. The Wendelstein 7-X employs a “stellarator” which consists of specially designed magnets that do not need a current to keep the reactor functioning.
“You want a fusion reactor to be on all the time, so you’d like not to have to push a large current around 24/7,” Professor Cowley at the Center for Fusion Energy in Culham, U.K., said. “Wendelstein is a natural design which does without the current. It gets the magnetic field controlling the plasma to twist, using weird-shaped magnets. It’s a different route to nuclear fusion.”
Cowley said that with the latest development scientists are optimistic that nuclear fusion reactors capable of generating almost unlimited supply of clean energy are probably only a few decades away.
Following success of the Wendelstein 7-X, researchers hope to build a stellarator that is is able to generate plasma from hydrogen at higher than one million degrees Celsius and control the plasma for up to 30 minutes.
[Image via Bernd vdB/Wikimedia]