The Wendelstein 7-X reactor is an
experimental stellarator built in
Greifswald, Germany, by the
Max-Planck-Institut für Plasmaphysik,
and completed in October 2015. It is a
further development of Wendelstein 7-AS.
The purpose of Wendelstein 7-X is to
evaluate the main components of a future
fusion reactor built using stellarator
technology, even if Wendelstein 7-X
itself is not an economical fusion power
plant.
The Wendelstein 7-X reactor is the
largest fusion device created using the
stellarator concept which was the
brainchild of physicist Lyman Spitzer.
It is planned to operate with up to 30
minutes of continuous plasma discharge,
demonstrating an essential feature of a
future power plant: continuous
operation.
The name of the project, referring to
the mountain Wendelstein in Bavaria, was
decided at the end of the 1950s,
referencing the preceding project from
Princeton University under the name
Matterhorn.
The research facility is an independent
partner project with the University of
Greifswald.
Design and main components
The Wendelstein 7-X device is based on a
five field-period Helias configuration.
It is mainly a toroid, consisting of 50
non-planar and 20 planar superconducting
magnetic coils, 3.5 m high, which induce
a magnetic field that prevents the
plasma from colliding with the reactor
walls. The 50 non-planar coils are used
for adjusting the magnetic field.
The main components are the magnetic
coils, cryostat, plasma vessel, divertor
and heating systems.
The coils are arranged around a heat
insulating cladding which is 16 meters
in diameter called the cryostat. A
cooling device produces enough liquid
helium to cool down the magnets and
their enclosure to superconductivity
temperature. The plasma vessel, built of
20 parts, is on the inside, adjusted to
the complex shape of the magnetic field.
It has 299 holes for plasma heating and
observation diagnostics. The whole plant
is built of five almost identical
modules, which are assembled in the
experiment hall.
The heating system includes 10 megawatts
of microwaves, for up to 10 seconds, and
can deliver 1 megawatt for 50 seconds
during operational phase 1. For
operational phase 2, after completion of
the full armor/water-cooling, up to 8
megawatts of neutral beam injection will
also be available for 10 seconds, while
the microwave system will be extended to
true steady state.
History
It was originally expected to reach
completion in 2006. The schedule slipped
into late 2015.
In 2012, Princeton University and the
Max Planck Society announced a new joint
research center in plasma physics, to
include research on W7-X.
The end of the construction phase was
officially marked by an inauguration
ceremony on 20 May 2014. After a period
of vessel leak-checking, beginning in
the summer of 2014, the cryostat was put
under vacuum, and magnet testing was
completed in July 2015.
The first plasma tests were scheduled to
begin during operational phase 1 in late
2015. A three-lab American consortium
became a partner in the project, paying
7.5 million Euros of the projected total
cost of 1.06 billion Euros.
See also
Large Helical Device
Helically Symmetric Experiment
National Compact Stellarator Experiment
References
External links
Wendelstein 7-X – Max-Planck-Institut
für Plasmaphysik
