The Wendelstein 7-X Stellarator: The Future of Nuclear Fusion

[stevebd1]

Here's an interesting article (from the magazine Science) about the Wendelstein 7-X Stellarator which is due to be switched on at the end of the month-

'The bizarre reactor that might save nuclear fusion'
http://www.sciencemag.org/content/350/6259/369.full

Construction video-

 

[Hercuflea]

What's interesting about this is it shows how fast fusion experiments can be built when not bogged down by the politics of a global regulatory committee like ITER. China is already making plans to build it's own tokamak that could be finished before DEMO.

 

[the_wolfman]

What's interesting about this is it shows how fast fusion experiments can be built when not bogged down by the politics of a global regulatory committee like ITER.

I'm really not sure how you reached this conclusion. W7-X was originally supposed to have its first plasma in 2006! It's hard to argue that a project was built quickly when it was completed almost a decade behind schedule.

 

[Hercuflea]

In fusion years, I'd say a decade is pretty quick! Considering ITER's first concept designs were in the 70's? And it's still nowhere near completion.

Granted, I realize W7X is a much smaller scale project but it does have it's own unique engineering challenges.

 

[the_wolfman]

The first ITER talks were in 1985. ITER was born out of the INTOR workshops. The first of which was in 78 or 79? The ITER treaty was signed in 2006 and construction of the ITER site started in 2008. Who knows when ITER will have first plasma.

The first W7-X design concepts were in the early 90's (93-94) following the unification of Germany. Construction of IPP Greifswald started in 94 and the construction of W7-X started around 2000. It was originally supposed to be completed by 2006. It took ~15 years to build W7-X and its over 20 years since the first design concepts.

For comparison it took 5 years to build JET, It took 5 years to build Alcator C-MOD. Design of NSTX started in 1995, assembly started in 1998, and first plasma was in 1999. (NSTX was built in the old TFTR pit and assembly only took a few months). I couldn't find any information of DIII (-D). The chiense EAST tokamak took 10 years, the Korean tokamak KSTAR took 13 years, and the Japanese Stellarator LHD took 8 years.

Don't get me wrong, I'm really excited for the start-up of W7-X. But its not the exemplar of an quick construction project. Not by fusion standards.

 

[Astronuc]

The DIII-D was first operated in 1986, and it's predecessor Doublet-III (or Doublet 3) was started around 1979, with construction in 1975.There is an EPRI report published in 1975 on Doublet-III and various texts cover Doublet-III and DIII-D.

EPRI 115-2 (Oct 1975) Fusion reactor studies: Doublet III design
https://inis.iaea.org/search/search.aspx?orig_q=RN:8345040

Tokamak Engineering Mechanics
DIII-D 1986

Theory of Tokamak Transport: New Aspects for Nuclear Fusion Reactor Design
Doublet III (or Doublet 3) 1979

Before Doublet-III, there was Doublet-II. I suspect that it is discussion in various journals on Fusion Engineering.
Confinement of Plasma in the Doublet-II Device

Nuclear Fusion: Half a Century of Magnetic Confinement
Doublet I preceded Doublet II (1972-1974). A table dates Doublet IIA (1974-1979), Doublet III (1978-1985). I believe Doublet III was a separate device, and Doublet II was scrapped.
https://www.crcpress.com/Nuclear-Fu...nt-Fusion-Research/Braams-Stott/9781420033786

DIII-D has received a number of upgrades since it's introduction.

https://fusion.gat.com/pubs-ext/SOFT04/A24793.pdf
https://fusion.gat.com/global/DIII-D

http://www.ga.com/magnetic-fusion-energy

A design retrospective of the DIII-D tokamak
http://iopscience.iop.org/article/1...ED2D0B60A017BD47F3E.c2.iopscience.cld.iop.org

The DIII-D tokamak evolved from the earlier Doublet III device in 1986. Since then, the facility has undergone a number of changes including the installation of divertor baffles and pumping chambers in the vacuum vessel, the addition of a radiation shield, the development of extensive neutral beam and RF heating systems, and the addition of a comprehensive plasma control system. The facility has become the focus of a broad fusion plasma science research programme. An integrated picture of the facility and its capabilities is presented.

 

[Astronuc]

Scientists in Germany switch on nuclear fusion experiment
https://finance.yahoo.com/news/scientists-inject-fuel-experimental-fusion-device-071639314.html

Wendelstein 7-X fusion device produces its first hydrogen plasma
http://www.ipp.mpg.de/4010154/02_16

February 03, 2016

The Wendelstein 7-X fusion device at Max Planck Institute for Plasma Physics (IPP) in Greifswald produced its first hydrogen plasma on 3 February 2016. This marks the start of scientific operation. Wendelstein 7-X, the world’s largest fusion device of the stellarator type, is to investigate this configuration’s suitability for use in a power plant.

Since the start of operation on 10 December 2015 Wendelstein 7-X has produced more than 300 discharges with the rare gas, helium. These served primarily to clean the plasma vessel. The cleaner the vessel wall, the more the plasma temperature increased, finally attaining six million degrees. In addition, plasma heating and data recording were tested, and the first measuring facilities for investigating the plasma were put into operation, viz. complex instrumentation such as X-ray spectrometers, interferometers, laser scattering and video diagnostics. “This makes everything ready for the next step”, states Project Head Professor Dr. Thomas Klinger. “We are changing from helium to hydrogen plasmas, our proper subject of investigation.”

The first hydrogen plasma, which was switched on at a ceremony on 3 February 2016 attended by numerous guests from the realms of science and politics, marks the start of scientific operation of Wendelstein 7-X.

http://www.ipp.mpg.de/16900/w7x

 

[mfb]

"Fusion" experiment.
They don't plan to have relevant fusion power in that device. It is a plasma experiment, although the plasma is mainly studied for future fusion reactors.

 

[Astronuc]

"Fusion" experiment.
They don't plan to have relevant fusion power in that device. It is a plasma experiment, although the plasma is mainly studied for future fusion reactors.

Perhaps a more correct description is "plasma physics" or "plasma stability" experiment.