
Germany is turning on its monster stellarator - radiorental
http://www.businessinsider.my/germany-is-turning-on-its-monster-stellarator-2015-10/#tqgboZYo4ZsctBCU.97
======
chasingtheflow
Source article: [http://news.sciencemag.org/physics/2015/10/feature-
bizarre-r...](http://news.sciencemag.org/physics/2015/10/feature-bizarre-
reactor-might-save-nuclear-fusion)

------
dang
[https://news.ycombinator.com/item?id=10437075](https://news.ycombinator.com/item?id=10437075)

------
jakeogh
Wendelstein 7-X - from concept to reality:
[https://www.youtube.com/watch?v=lyqt6u5_sHA](https://www.youtube.com/watch?v=lyqt6u5_sHA)

Im Zeitraffer: Zusammenbau von Wendelstein 7-X:
[https://www.youtube.com/watch?v=MJpSrqitSMQ](https://www.youtube.com/watch?v=MJpSrqitSMQ)
(best @ 0.56x)

Previously:
[https://news.ycombinator.com/item?id=10437075](https://news.ycombinator.com/item?id=10437075)

More: [https://www.youtube.com/channel/UCAx243-m51RI-
k_4lsAqidA/fee...](https://www.youtube.com/channel/UCAx243-m51RI-
k_4lsAqidA/feed)

~~~
justifier
the first video claims a magnetic field strength of 2.5 Tesla(o) roughly that
of an MRI(i)

can anyone speak to sort of considerations that lead to this value? 2.5T seems
insignificant considering the events it will be confining

how sensitive is the field to magnetic interactions outside of the device?

(o) [https://youtu.be/lyqt6u5_sHA?t=301](https://youtu.be/lyqt6u5_sHA?t=301)
(i)
[https://en.wikipedia.org/wiki/Tesla_(unit)#Examples](https://en.wikipedia.org/wiki/Tesla_\(unit\)#Examples)

~~~
jessriedel
Steady magnets can't get much stronger than that. The very strongest steady
magnets, purpose built, are in the 40-70 tesla range. I believe the limit is
set by the break down of normal matter. Higher field strengths can be
achieved, but only for fractions of a second and are general destructive.

~~~
madaxe_again
Imploding coils. This stuff gets me every time I see it - chills down the
spine. You can induce a field in the _MEGA_ tesla range for an infintesimal
amount of time. Take a copper (or superconductor, if you're feeling ballsy)
coil, run a huge current through it from your enormous capacitor bank, set off
a wad of high explosive surrounding the apparatus - the near-instantaneous
collapse of the conductor causes the field within to become absolutely
enormous - and equally importantly the Ts-1 - i.e. the rate of change of the
field - again, you can induce enormous currents outside of the apparatus
through induction.

This technique is mostly used in solid state and, surprise surprise, fusion
experiments. Oh, and you can make an EM bomb if you make a big enough one, and
wipe out a city's electronic infrastructure in a microsecond.
[https://en.wikipedia.org/wiki/Explosively_pumped_flux_compre...](https://en.wikipedia.org/wiki/Explosively_pumped_flux_compression_generator)

------
frooxie
I'm glad that Germany now has the option of stellarating the monsters they
capture.

EDIT: On reading further, it turns out I may have misinterpreted the article.

~~~
raverbashing
Even better if they make a portable version and call it Mr. Fusion

------
ThePhysicist
I once did an internship at the MPI in Garching and had the opportunity to
visit the Stellarator. Although it looks much less spectacular with all the
coils hidden in their housing it is still an incredibly impressive machine
with an audacious design.

Today the numerical effort required for realizing it might seem not very
impressive given the technological capabilities that we have, but you have to
take into account that the first version (Wendelstein 7-AS) was built in the
1980s already.

That said I really hope that the experiment confirms the viability of this
design and its (potential) superiority compared to the classical Tokamak
fusion chamber.

~~~
zamalek
I have no doubt that a design that goes with the physics (instead of going
against it like Tokamaks do) is going to yield great results, however I hope
something comes out if it that will also allow for viable Tokamaks.
Stellarators are hellishly complex and expensive.

~~~
drjesusphd
Can you explain what you mean by tokamaks "going against the physics"?

~~~
kuschku
Tokamaks need, to contain the plasma, a continuously changing magnetic field.
To create a continuously changing magnetic field, you need to continuously
increase or decrease the current.

The issue is that you can not turn up the current more than a maximum level,
and you have to keep the direction the same (so you can’t switch between
turning off and on).

Stellerators instead solve this with complex geometry and the plasma creating
its own continously changing magnetic field.

~~~
drjesusphd
> Tokamaks need, to contain the plasma, a continuously changing magnetic field

Do you have a citation for this claim?

~~~
kuschku
I could source one from German Wikipedia, but english wikipedia does not seem
to have that information.

You might be able to find some sources when you search for the reasons of
Tokamaks pulsed usage.

------
InclinedPlane
This is likely to be more important, for much less expenditure, than ITER.

Edit: to add some additional context, the main problem with fusion reactors is
confinement time and plasma stability. The general idea of a fusion power
plant using magnetic confinement is that a gas is turned into plasma, confined
magnetically, and heated until it can undergo significant fusion reactions.
There are two core problems to creating fusion plasmas that could potentially
produce power. One is pumping the plasma up to conditions that enable self-
sustaining fusion by maintaining a high enough temperature from balancing the
heat losses in the plasma against the heat gains from fusion reactions. The
other is producing more energy from fusion reactions than was put into heating
and containing the plasma. The longer the fusion plasma is contained the
longer it has to continue fusion reactions and producing energy.

Tokamaks are easy to build but have a fatal flaw in that they have high plasma
current, which makes them difficult to control with very unstable plasmas.
Stellarators are vastly more difficult to build but they don't rely on
currents in the plasma itself, which offers the potential for vastly longer
confinement times.

~~~
nabla9
This is wrong comparison.

Wendelstein 7-X is small early experimental reactor for testing stellator
geometry for reactor. Research questions are similar to where JET (the largest
working tokamak today) was 30 years ago. Stellator is more complex design but
promises inherently stable containment.

ITER is solving different questions. ITER solves engineering problems for
full-scale electricity-producing reactor that would be practical to build and
operate. JET studied containment in Tokamaks. ITER is the last step before
first industrial fusion reactor design DEMO (Demonstration Power Plant).

There is also lots of technical overlap of course. Vacuum vessels, cooling,
magnets, breeder blankets, etc. ITER is developing these for industrial-scale
reactor, even for stellator.

~~~
XorNot
This is exactly right. Regardless of which technology proves viable first, the
reactors will have their parts built in the same factories.

------
mdellabitta
> The key to a successful nuclear reactor of any kind is to generate, confine,
> and control a blob of super-heated matter, called a plasma — a gas that has
> reached temperatures of more than 180 million degrees Fahrenheit.

Um, what? I'm about to pass a nuclear fission plant on my way to work, and I
surely hope there are no plasmas in _that_.

AKA, they mean _fusion_ reactor.

~~~
XorNot
Nucleons are reacting. It's most definitely a nuclear reactor of some type.

~~~
kohanz
_nuclear reactor of any kind_

They're not disputing the _nuclear_ term, but _fission_ vs. _fusion_.

~~~
mdellabitta
Ding ding ding.

Also, hello from Indian Point, Buchanan, NY! I can see a containment dome as I
write this.

Next up on my Snake Plisskin-esque commute is literally going through Sing
Sing prison:
[https://www.google.com/maps/@41.1506265,-73.8700067,613m/dat...](https://www.google.com/maps/@41.1506265,-73.8700067,613m/data=!3m1!1e3?hl=en)
(those train tracks are the Metro North Hudson line, among other things)

------
prodmerc
"Designed in Hell" \- really? Goddamn, I hate modern media outlets...

~~~
creshal
Hell, CA; Hell, MI; Hell, AZ; Hell, Norway; or Hell, Netherlands?

~~~
prodmerc
Hell, the Devil's playground... because it looks strange.

What kind of association does that make in people's minds, they already think
nuclear = death...

------
lucaspiller
Assuming these experiments work as desired and this reactor can produce more
energy than it takes in, how long will it be (roughly) until a power plant
becomes operational (i.e. connected to the grid) that uses this technology?
Years, a decade, many decades?

~~~
creshal
It's not yet designed to produce net energy – it can't handle the necessary
(radioactive) tritium fuel.

Assuming it works as intended, the next step would be a research reactor that
can, _that_ would be a pilot project to generate net energy which could be
connected to the grid (probably more for symbolic reasons at that point…) and
breed tritium for further reactors.

 _Then_ we can start to plan building actual power plants. So, few decades, as
always.

~~~
rbanffy
I guess we can still say it will be the most important energy source over the
next millennium...

------
adrianN
Good to see that there is enough money to pursue stellarators while
simultaneously working on tokamak designs like ITER.

~~~
hahainternet
I was chatting about this with a friend and there are something like 5
different in production technologies which produce or cause nuclear fusion.
Only three I think are aimed at sustainable power generation, but it's still
pretty cool.

~~~
campers
I hadn't heard of this one before, always interested in fusion news. 3 others
I know about are

[http://www.generalfusion.com/](http://www.generalfusion.com/)

[http://lawrencevilleplasmaphysics.com/](http://lawrencevilleplasmaphysics.com/)
(Focus fusion)

[http://www.lockheedmartin.com/us/products/compact-
fusion.htm...](http://www.lockheedmartin.com/us/products/compact-fusion.html)

~~~
DennisP
Tri-Alpha is the biggest private effort...about $200 million invested, 30
Ph.Ds, 150 employees. They recently announced they'd achieved stable plasma,
the only major milestone left is scaling up the temperature. They think the
plasma will get more stable at higher temperatures. Like focus fusion, they're
attempting boron fusion.

Helion is similar to Tri-Alpha but with a pulsed design instead of steady
state. They have funding from YCombinator. Instead of boron they're shooting
for a hybrid D-D/D-He3 fuel cycle (the D-D reaction produces He3). They say
only 6% of the energy released would be as neutron radiation.

Sandia's MagLIF project is interesting. According to their computer
simulations they can get 100x to 1000x energy gain by preheating a fuel
capsule and crushing it in an upgraded Z-Machine. Things are looking good so
far.

UW has the Dynomak project, which is fairly similar to tokamak but a lot
smaller and cheaper. They need $10 million to test the concept.

------
semiquaver
Better article: [http://www.economist.com/news/science-and-
technology/2167675...](http://www.economist.com/news/science-and-
technology/21676752-research-fusion-has-gone-down-blind-alley-means-escape-
may-now-be)

~~~
jedberg
Thanks! The diagram at the top of that one made more sense than the entire OP
article.

------
sheraz
Wow - it looks like very Steampunk with all those valves and ports.

~~~
stargazer-3
Looks more like modern art to me.

------
csvan
This is one of the greatest events in the history of energy research. Really,
really hoping that the upcoming results of the machine will at least meet
expectations.

------
dgudkov
A naive question - if this kind of reactors start producing more energy than
consuming, what kind of fuel would they need? AFAIK the Sun slowly burns
hydrogen into helium. Does it mean that stellarators would only need hydrogen
to operate? That would be basically free energy.

~~~
Tuna-Fish
Fusion reactors can use different fuels based on how good they are at
containing plasma.

Right now, almost all research is directed towards the easiest possible fuel
that requires least powerful containment, that is, Tritium (H3) and Deuterium
(H2). Deuterium can be separated from water, and Tritium can be bred from
Lithium using waste neutrons.

T+D is inexhaustible, but also quite expensive as both separation and neutron
breeding are relatively expensive. However, as a fusion reactor consumes tiny
amounts of fuel per unit of energy, a T+D reactor could potentially still run
profitably.

If we get better at containing plasma, other fuel choices become available.
Most important being Boron + Hydrogen, which would be inexhaustible, cheap,
and produces minimal neutrons during fusion, making it easier on the
equipment.

However, free fuel doesn't mean free energy. The cost of all nuclear power,
including current fission power, is utterly dominated by the capital cost of
equipment.

------
lnkmails
It doesn't say how many watts of power this machine would produce and what is
the cost to produce per watt? It would be interesting to compare numbers and
see if this machine would ever see mass production in next few decades.

~~~
ju-st
Zero watt. It's a research reactor. And they don't want to use tritium (which
is apparently needed for power generation) because it would cause radiation.
And radiation is bad when you want to do research on the reactor. Source:
German wikipedia

~~~
creshal
> And radiation is bad when you want to do research on the reactor.

As in, you want to partially disassemble and tweak the reactor regularly.
Neutron activated metals will be radioactive enough after a while, no need to
make things worse by adding tritium to the mix.

------
Aardwolf
That machine looks absolutely beautiful to me, I love the design. It would
also be perfect for in movies and computer games :)

------
penetrarthur
When exactly is it turned on?

~~~
deweller
That was not reported. This is what was reported on Oct. 23rd by
sciencemag.org:

"Approval to go ahead is expected from Germany's nuclear regulators by the end
of this month"

------
frandroid
Tell me that doesn't look like it came straight out of Akira... :)

------
ps4fanboy
"Designed in hell" low class.

------
jlebrech
I'm still waiting on LFTR.

~~~
DennisP
Uranium-fueled molten salt reactors will probably happen first; they'd have
the same safety advantages but without the huge extension of fuel supply that
you'd get from thorium breeding. Some designs would be more proliferation-
resistant than LFTRs. Startups attempting it include Terrestrial Energy,
Transatomic, ThorCon, Moltex, and Seaborg.

------
insulanian
That's how Germans do it - they keep quiet and just do it. Respect!

~~~
flexie
Sometimes they keep it very quiet:
[https://en.wikipedia.org/wiki/Volkswagen_emissions_scandal](https://en.wikipedia.org/wiki/Volkswagen_emissions_scandal)

No, seriously. All these statements about German character or German mentality
should stop. If the last few months haven't taught us anything else, at least
it should have taught us that. First, Germans and the German government were
praised as reliable in connection with the Grexit (as opposed to the Greeks),
then a few months later, a German government owned car producers is caught in
what might be the biggest corporate fraud ever.

I wonder if mentality and national traits even exist.

~~~
kuschku
And how did VW handle it?

CEO resigned, 10 board members suspended, all non-management employees
(engineers, programmers, etc) have full immunity, even if they worked on the
defeat device.

That’s the most honorable reaction one could expect, and it allows to get rid
of the issue.

~~~
archon
> all non-board employees have full immunity, even if they worked on the
> defeat device

I'm not trying to pick a fight, but how is that in any way honorable?

~~~
kuschku
Because this defeat device is nothing you should blame on a single engineer,
it is clearly a systematic issue, and normal engineers should not be held
accountable for actions that the CEO and board forced them to do.

~~~
vidarh
On the other hand it teaches those on the ground that obeying illegal orders
is perfectly fine, because, hey, you won't get punished.

~~~
kuschku
It is also the only way you get people ever providing evidence against their
boss, as otherwise they'd risk incriminating themselves.

~~~
vidarh
You can support that goal by offering immunity to whistleblowers.

~~~
kuschku
Well, offering immunity to everyone who just followed orders is an important
part of doing so. And it makes in this case everything a lot easier.

~~~
vidarh
Offering immunity to everyone who just followed orders is far more drastic
than offering immunity specifically _only_ to those who _actually_ takes the
step of whistleblowing before the issue becomes known.

The former creates no incentive to be a whistleblower - it just takes away one
of the risks of doing so. The latter creates a strong incentive to be the
first to report something.

------
ck2
Every week I learn something new to admire about Germany.

Or at least its responsible investment behavior by its government.

USA would not build such a thing in today's political climate of nonsense
unless it had weapons research possibilities.

~~~
kuschku
Actually, the US invested in both the National Ignition Facility for H-Bomb
and Fusion research, and in ITER.

Just because the US invests _rarely_ in civilian research doesn’t mean they
_never_ do (compared to military research; compared to other countries they
still invest a lot in civilian research)

~~~
ck2
NIF is weapons research, hence my point.

Congress won't fund a civilian space shuttle anymore but we spend billions for
the military to have their own.

Like I said, if it's not about killing people, destroying things and spying on
the world (including our own people) we pretty much won't spend money on it
anymore here.

Germany did the investment beyond war.

