2013 May - Fusion Field Trip to Wendelstein 7-X

The first Stellarator Study Tour

The first study tour of the Master “Science and Technology of Nuclear Fusion” had Wendelstein 7-X as destination. Fourteen students went to the small university town Greifswald to visit the stellarator under construction.

A stellarator is a magnetic confinement fusion device that does not need a plasma current, but instead uses a twisted magnetic topology to keep the particles together. One main advantage is that this concept is inherently steady state. The stellarator has high potential to become the ultimate fusion reactor.

A billion dollar Project

Wendelstein 7-X is a billion dollar German project of the Max Planck Institute for Plasma Physics (IPP). The assembly will finish in 2014, followed by a few years of commissioning. Long pulse operation is scheduled in 2018 – however no reactor levels will be achieved in its lifetime, because the plant will not be equipped with a tritium facility (hence no DT-fusion).

The evolution of the Stellarator concept

The Wendelstein crew organized a perfectly suited programme for the fusion students, who base their fusion knowledg mainly on tokamaks. The day started with an introductory talk on the project. The following lecture was about the evolution of the stellarator concept towards the current. Very instructive was to see that the modular coils were obtained from a smart combination of the toroidal field coils and helical field coils, giving the same magnetic field.

Students meet Machine

The plus 700 tonnes machine was finally met during the tour. A few months earlier the plasma vessel was closed. The 16 meters wide beast exists of five identical modules.

ECRH heating

The after lunch lecture covered the ECRH (electron cyclotron resonance heating) system, followed by a tour around the underground generation compartments. Through a tunnel via copper mirrors, 10MW microwave radiation is guided to the stellarator hall. The next photo shows the group next to one of the impressive light canons, with controllable aiming mirrors.

Tokamak or Stellarator - a lively discussion

The knowledge and frankness of the Wendelstein crew members formed the base of a lively discussion at the end of the day, in which the feasibility and potential competition with the tokamak development path were discussed as well.

An inspiring trip to Greifswald

After the full day there was time for a beer tasting and dinner in “Der Alter Fritz” in the old city centre of Greifswald.

Conclusion: This stellarator project is a tremendous one and worth a visit for any fusion student. The “Gründlichkeit” that the Germans embrace, is inspiring for anyone who wants to see how a large project has to be managed.

Thanks

Many thanks to the organizations that made our trip possible:

  • The ‘Nederlandse Natuurkundige Vereniging’ is the dutch physicist’s association. It promotes the interests of physics and organizes physics activities. All members receive the magazine ‘Nederlands Tijdschrift voor Natuurkunde'.