German researchers make nuclear fusion breakthrough
17 December 2015
Scientists at Germany’s Max Planck Institute for Plasma Physics (IPP) have switched on a massive reactor that could provide the basis for future electricity generation by nuclear fusion. The Wendelstein 7-X nuclear fusion device is the largest stellarator-type reactor ever built and is the product of more than nine years of construction, one million installation hours, and a budget of over one billion euros.
Plasma in the Wendelstein 7-X nuclear fusion device - Image: IPP
On December 16, the IPP announced the device had been switched on the previous week creating a helium plasma - a cloud of loose, charged particles – which lasted a tenth of a second at a temperature of one million degrees Celsius.
“We’re very satisfied”, Hans-Stephan Bosch, whose division is responsible for the device’s operation, said following the experiment. “Everything went according to plan.”
This has been hailed as a breakthrough for nuclear fusion, the holy grail of clean and cheap energy and the process by which the sun is powered.
The stellarator is a radically different design from the tokamak devices used elsewhere in fusion research. The team at Greifswald, in northeastern Germany, aim in future to heat hydrogen nuclei to about 100 million C - the necessary conditions for fusion to take place like in the Sun's interior. They will use deuterium, an isotope, of the element.
To create the plasma, the researchers used a microwave laser pulse of 1.3 megawatts, a complex combination of magnets and 10mg of helium in the experiment.
Researchers were satisfied by the initial results, and will now begin testing longer longer discharges to determine the “best method of producing and heating helium plasmas” using the microwaves.
“We’re starting with a plasma produced from the noble gas helium. We’re not changing over to the actual investigation object, a hydrogen plasma, until next year,” project leader Professor Thomas Klinger said.“This is because it’s easier to achieve the plasma state with helium. In addition, we can clean the surface of the plasma vessel with helium plasmas.”
The EU's main nuclear fusion project is called Iter, at Cadarache in the south of France, scheduled to start up in the 2020s. Iter will be a tokamak device and has already cost more than €10bn.
Scientists have been working on nuclear fusion for more than 50 years but the extreme temperatures involved and the difficulty of controlling plasmas mean progress is slow. The goal is to release abundant energy without the volumes of toxic waste generated by fission, the technology currently used in nuclear electricity production.