Wendelstein 7-X

The Wendelstein 7-X reactor is an experimental stellarator built in Greifswald, Germany, by the Max Planck Institute for Plasma Physics, and completed in October 2015. Its purpose is to advance stellarator technology: though this experimental reactor will not produce electricity, it is used to evaluate the main components of a future fusion power plant; it was developed based on the predecessor Wendelstein 7-AS experimental reactor.

As of 2015, the Wendelstein 7-X reactor is the largest stellarator device. It is designed to achieve enclosure of up to 30 minutes of continuous plasma discharge in 2021, thus demonstrating an essential feature of a future fusion power plant: continuous operation.

Source: Wikipedia