Fusion for the future

The possibility of a fusion-fuelled future moved one step closer as construction of an experimental plant in northern Germany reached a milestone.

The Wendelstein 7-X fusion device being assembled at the Greifswald branch of Max Planck Institute of Plasma Physics (IPP) will form the heart of the world's largest stellarator type fusion experiment.

The first two half-modules are complete, and a fifth of the inner core of the device is being assembled. Most components have been fabricated and construction of the device will take another six years.

In a fusion reactor, hydrogen plasma has to be confined in magnetic fields and heated to temperatures of more than 100mºC. The Greifswald experiment will investigate whether this concept is sustainable for a power plant by conducting discharges lasting up to 30 minutes to demonstrate the stellarator is capable of continuous operation.

The core of the device will soon be completed. It consists of 50 superconducting magnet coils about 3.5m high, which will provide a stable and thermally insulated magnetic cage for the plasma. A second set of 20 planar, superconducting coils manufactured by the UK's Tesla will operate alongside the stellarator coils to vary the magnetic field.

The cryostat, a thermally insulating outer casing 16m in diameter, will enclose the entire coil construct. Two sections have been completed by MAN DWE in Germany.