December 7, 2016

Tests confirm German ‘star in a jar’ fusion reactor really works

A massive, tremendously complicated nuclear fusion reactor theoretically capable of producing far more energy than current nuclear plants without the harmful waste products appears to be working as its creators intended, according to a new study.

Known as the Wendelstein 7-X, the fusion energy device uses a design called a stellarator that confines hot, charged gas (also known as plasma) to fuel reactions in twisted, 3D magnetic fields rather than the symmetrical, 2D fields typically created by more commonly used systems.

Those standard devices, called tokamaks, involve a ring of magnets which force nuclear material to travel along a large circle, Popular Mechanics explained. However, the stellarator adds several twists to the configuration in order to reduce the risk of disruption and increase stability.

The Wendelstein 7-X was activated last year, and was able to contain helium plasma, according to ScienceAlert. However, since it was first switched on, experts had wondered if the technology was working according to specifications. A team of US and German researchers investigated the matter, reporting in the journal Nature Communications that things are going as planned.

A step forward, but fusion energy is still a long way off

In fact, Sam Lazerson, a physicist at the US Department of Energy’s Princeton Plasma Physics Laboratory (PPPL) in New Jersey, and his colleagues reported that the Wendelstein 7-X is now producing 3D magnetic fields with “unprecedented accuracy.” Specifically, they found that the machine has an error rate of less than one in 100,000, according to ScienceAlert.

“This is a significant step forward in stellarator research,” Lazerson and his co-authors wrote, “since it shows that the complicated and delicate magnetic topology can be created and verified with the required accuracy.” The findings, the researchers added in a press release, could be “a key step toward verifying the feasibility of stellarators as models for future fusion reactors.”

What makes this such a big deal? As Popular Mechanics explained, nuclear fusion is a reaction similar to those used by stars like the Sun, and when compared to currently used nuclear fission plants, fusion reactors would produce far greater amounts of energy and much less waste. In fact, they are theoretically capable of producing “nearly limitless energy” using only seawater as fuel and without producing byproducts such as radioactive waste, the website noted.

Now that Lazerson’s team has demonstrated that the Wendelstein 7-X’s stellarator, which was originally designed as a proof-of-concept, works, the developers can now work on creating new designs that improve the efficiency of the device, said ScienceAlert. Using the longevity of the Sun as a model, scientists believed that nuclear fusion could eventually supply the planet with an unlimited amount of energy – provided they can adequately harness the reaction, that is.

While researchers have been working on this problem for several decades, the success of the Wendelstein 7-X’s stellarator thus far appears to be a promising step forward. While the device isn’t actually designed to generate electricity from nuclear fusion, the tests indicate that it could actually work. However, Lazerson’s team pointed out that it will take “years of plasma physics research” to determine if the stellarator is indeed the best way to achieve fusion energy.


Image credit: Nature Communications