
Livestream of Wendelstein 7-X Stellerator being turned on - rkangel
http://www.ipp.mpg.de/livestream_e_16
======
lorenzhs
For anyone tuning in now, the event is already over, and German media report
that it was a success. I can't find a decent English-language source yet,
surely there will be reports on it soon. Most of the German articles have lots
of immediately obvious inaccuracies as well right now...

EDIT: There's another post on the front page right now that has a recording of
the event: [http://www.iflscience.com/physics/watch-germany-switch-
their...](http://www.iflscience.com/physics/watch-germany-switch-their-
experimental-fusion-reactor-live) discussion at
[https://news.ycombinator.com/item?id=11026559](https://news.ycombinator.com/item?id=11026559)

~~~
pmontra
The video is in English. You can skip to about 38:00 and watch the ignition
sequence and listen to some explanations from the speaker.

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iokevins
From Wikipedia: The Wendelstein 7-X (W7-X) reactor is an experimental
stellarator (nuclear fusion reactor) built in Greifswald, Germany, by the Max-
Planck-Institut für Plasmaphysik (IPP), 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 Project Matterhorn.

[https://en.wikipedia.org/wiki/Wendelstein_7-X](https://en.wikipedia.org/wiki/Wendelstein_7-X)

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mabbo
The tl;dr of this is that if the Wendelstein works, and works well, we're
potentially only a few years away from building a fusion reactor that
generates large amounts of clean power at extremely low cost.

If it doesn't work, well, they'll keep trying.

It's like when SpaceX landed that rocket over the ocean (without a barge) then
let it crash- if they succeed, the cool stuff comes next.

~~~
celticninja
im not sure they let it crash, i think that bit was an accident.

~~~
maxerickson
They didn't stick a barge under it for the early tests:

[https://en.wikipedia.org/wiki/Falcon_9_booster_landing_tests...](https://en.wikipedia.org/wiki/Falcon_9_booster_landing_tests#Ocean_water_test_descents)

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ajmurmann
Can you imagine the chancellor our president coming by for a launch event when
you run your software for the very first time that you've never run before not
even I an integration test after coding on it for years?!

~~~
Phlarp
I suspect they had a very robust testing regime for both the software and the
hardware used in this project. As well as more formal mathematical proofs of
the physics to back up their engineering.

A better analogy might be for rockets / spaceflight-- where individual systems
are rigorously tested independently, but a live launch is the only place that
they all come together and have to function as one tightly coupled system.

~~~
engi_nerd
> A better analogy might be for rockets / spaceflight-- where individual
> systems are rigorously tested independently, but a live launch is the only
> place that they all come together and have to function as one tightly
> coupled system.

I understand the point that you are trying to make, but your analogy is a bit
poorly chosen.

Speaking from my days as a sounding rocket telemetry engineer, we performed
lots of tests of the individual systems, as you say. But then we also put
everything together and performed several "sequence tests" where the entire
vehicle (minus the motor) was assembled and tested as if the countdown were
real. All events were triggered as if the vehicle were in flight, and
experiment systems were tested to ensure they would power on as expected and
provide real data. If we had any deployables, the deployment mechanism would
be tested to the maximum extent possible. These sequence tests happened off
the rail (in special testing facilities) and on the rail (fully assembled in
launch configuration, with a motor).

Basically, if you wait until the actual launch to perform integration tests of
all of this, you WILL fail. There are too many pieces that need to function in
concert to expect them to all work without integration testing.

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numlocked
I've read a lot about the design and construction of the 7-X, but I've never
read why there are so many "portholes" all over the thing. There are a
comically large number of them, everywhere, of totally different sizes,
shapes, and at weird angles. Why are so many holes/ports necessary, and why is
there so little homogeneity?

~~~
the8472
> Why are so many holes/ports necessary

It's designed to be maintained from the inside. So you need to get
replacement/upgrade/experiment parts inside where you need them.

> and why is there so little homogeneity?

stellarators are highly asymmetrical

~~~
theoh
It does appear to have five-fold rotational symmetry, at least in the way the
coils are distributed.

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dest
Pictures of amazing W7X magnets, if I am not mistaken
[https://imgur.com/a/We3fk](https://imgur.com/a/We3fk)

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dalbin
Direct access to the stream :
[http://webcast.nc3-cdn.com/clients/mpg/2016/02/03/en/](http://webcast.nc3-cdn.com/clients/mpg/2016/02/03/en/)

~~~
mariuolo
Am I missing something or the actual turning on was not shown?

Perhaps later today?

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superkuh
It was shown. It lasted for a bit less than a second. They are not running it
longer right now because they cannot handle the thermal load.

~~~
mariuolo
Well, it's on youtube. Will check again, thanks.

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Geee
Time-lapse video of the building process
[https://www.youtube.com/watch?v=MJpSrqitSMQ](https://www.youtube.com/watch?v=MJpSrqitSMQ)

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maremmano
apparently it worked:
[https://translate.google.it/translate?sl=auto&tl=en&js=y&pre...](https://translate.google.it/translate?sl=auto&tl=en&js=y&prev=_t&hl=it&ie=UTF-8&u=http%3A%2F%2Fwww.zeit.de%2Fwissen%2F2016-02%2Fwendelstein-7-x-wasserstoff-
plasma-greifswald&edit-text=)

~~~
lorenzhs
There's an egregious mistranslation in there. In a section where nuclear
fusion is compared to fission, the German article reads

    
    
        Das ist ungefährlicher und hinterlässt weniger stark verstrahlten Atommüll 
    

the translation is

    
    
        This is dangerous and leaves less severely contaminated nuclear waste
    

whereas it should be

    
    
        This is *less* dangerous and leaves less strongly contaminated nuclear waste
    

The translation completely negated the sentence. The rest is pretty okay-ish.

~~~
bassislife
less dangerous? or "not more" dangerous?

~~~
captainmuon
literally more non-dangerous

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Eduard
literally "safer"

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DasIch
Safer has a connotation of safety whereas ungefährlicher has a connotation of
danger.

If something that would have killed you before, is less likely to do so now
you would call it ungefährlicher or less dangerous but you wouldn't call it
safer unless you're intending to be funny.

~~~
_ph_
Native German here: ungefährlich means "not dangerous" also "safe" or
"harmless".

~~~
bassislife
so "=== gefahrlos" ?

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frik
On 10th December 2015 the have done almost the same experiment:
[https://youtu.be/R_kPM1J-F0Q?t=3m49s](https://youtu.be/R_kPM1J-F0Q?t=3m49s)

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maga
What are the results? I've read they were going to keep the plasma stable for
half an hour, have they been able to do that?

~~~
obsurveyor
No, they want to do this by 2020.

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IanCal
A bit of googling didn't hit on much, but is there a plan for what happens in
the future if this continues to go well? In the same way that ITER would be
followed by DEMO then hopefully more commercial reactors.

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thrownaway2424
How do you take energy off one of these?

~~~
sbierwagen
Just by using it as a regular heat source to boil water, then running the
steam through turbines, like any other thermal power plant.

There are schemes to convert charged particle flux directly into electricity,
but I'm not aware of any fusion power experiments that use them:
[https://en.wikipedia.org/wiki/Direct_energy_conversion](https://en.wikipedia.org/wiki/Direct_energy_conversion)

~~~
thrownaway2424
That was a little bit vague. How does the heat actually get out of this thing
and into the water? If the plasma is confined in a magnetic field, not in
contact with the shell, and the shell is super-cooled to 4K, I'm a little lost
on how it would work in practice.

~~~
avar
If you step outside during the day you can have first-hand experience of a
contained fusion reactor that manages to heat things up at a distance.

That's how we'll extract energy from fusion reactors, but with approximately 1
AU less distance.

~~~
Frenchgeek
( unless things go comically wrong )

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anc84
> Fehler: Die Webseite 'www.ipp.mpg.de' ist momentan nicht verfügbar

