14 ms·

Wendelstein 7-X stellarator getting ready for the next phase of operation [pdf]

122 points by clon 9y ago

mandelken 9y ago
only 10 years too late..
- Gravityloss 9y ago
  The earlier, the better. Can someone say at what point we should stop trying?
  - rb1 9y ago
    The point when the black line on the graph goes below 0 http://i.imgur.com/sjH5r.jpg http://i.imgur.com/sjH5r.jpg (from: https://hardware.slashdot.org/story/12/04/11/0435231/mit-fusion-researchers-answer-your-questions https://hardware.slashdot.org/story/12/04/11/0435231/mit-fus...)
    - nomercy400 9y ago
      That only explains why the Wendelstein 7-X isn't being made in the US.
- Cerium 9y ago
  The best time to plant a tree was 20 years ago. The second best time is today.
- DesiLurker 9y ago
  my prediction is we'll have fusion net positive within a decade of when alternative energy's growth is significant enough to show up in fossil fuel economy's future projection. oh and no its not too late. if you have cheap and plentiful energy from fusion you can take on massive geoengineering projects to reverse global warming. its a whole another ballgame!
  - zlynx 9y ago
    But where are you putting the waste heat from everybody's personal Mr. Fusion reactor? Just imagine if everybody on Earth has a personal, nearly free 10 megawatt generator. Flying cars. Laser weapons. Direct desalination of seawater in coastal cities. Stomping around in powered exoskeleton suits. Anyway, it would be awesome. But where do we put all the heat?
    - DesiLurker 9y ago
      you are right, Waste heat would be a problem because the only way you can dissipate it is by radiation. but that would become a problem much much farther out. I mean we are talking 100+ billions people. Also, if you have plentiful energy you can build way cheaper orbital launch tech. translation you are not bound to earths gravity well anymore. So its not too far fetched to imagine living in space habitats (forget mars that just good for gravity). those will be much better at dissipating waste heat (volume/surface area thing). Like I said its a whole another ballgame.
mrfusion 9y ago
What's the next phase? When does it start? (I don't know if there's a problem with my reading comprehension or what?)
- clon 9y ago
  From the source: In preparation for the next operation phase (OP 1.2a), which is scheduled to start in late summer of this year, the limiter structures have been replaced by a test divertor and all graphite tiles on the baffles and wall protection elements have been installed. This will allow the use of more heating power and access to the required magnetic field configurations.
- ZenoArrow 9y ago
  There's no specific date mentioned, but the PDF does mention 'late summer' of this year. Looks like they're about halfway along with preparing the graphite tiles for the next phase (4500 out of 8000).
colonelxc 9y ago
Home page for the project, which provides some higher level details: http://www.ipp.mpg.de/w7x http://www.ipp.mpg.de/w7x
shaqbert 9y ago
Wendelstein 7-x is really not fusion research, but plasma physics research. At the energy/temperature levels and magnetic field strength this machine is operating, plasma is showing all kinds of undesirable behavior, such as turbulence, radial forces... a little bit like the storms on Jupiter. This imposes many challenges, because as soon as the plasma escapes the magnetic field and touches the vessel, it rapidly cools - ending any potential fusion. Wendelstein's goal is to find out the viability of the stellarator concept, to see if it could be on par with the Tokamak concept, which so far have shown a better ratio of energy invested and energy won back, but come with their own bag of problems. What the folks at Wendelstein are doing is a step by step verification of some of the hypothesis. There is this excellent 3h podcast with the scientific leader of Wendelstein [0], unfortunately it is in German. It is fascinating to hear their story on how they build this ultra complex piece of kit. The current change is the shielding of the vessel, which now permits higher energy levels and longer runs. Their long term goal is to operate at 100m K for 30 min. Regarding the "when we should stop trying" and "it is 30 years out" adage: There has been great progress made in improving the ratio of energy invested and energy won back, the G-factor. Right now no fusion reactor is crossing the G > 1 limit. But Iter would be design to yield about G = 5. Newer designs using high temperature superconductors could even yield G > 10 with a smaller footprint. For more on the current state of fusion research, this video [1] from MIT is fantastic, albeit 1h long. [0]: http://alternativlos.org/36/ http://alternativlos.org/36/ [1]: https://youtu.be/L0KuAx1COEk?t=37m23s https://youtu.be/L0KuAx1COEk?t=37m23s
- sandworm101 9y ago
  But how much of that G > 1 energy has ever been harvested? I get the impression that very little is being done in regards to extracting energy from a sustained fusion reaction. We can't put solar panels in there, nor can I see how one would extract heat given the cooling needs of the magnets. Is there some sort of medium that we can use to pipe heat energy out of this plasma without destroying it?
  - PhasmaFelis 9y ago
    > But how much of that G > 1 energy has ever been harvested? None, because we haven't achieved G > 1 yet. :) Per https://physics.stackexchange.com/questions/70209/how-is-energy-extracted-from-fusion https://physics.stackexchange.com/questions/70209/how-is-ene..., hydrogen fusion produces helium and neutrons; neutrons are unaffected by magnetic fields, so they escape confinement and impact the reactor walls, heating them. The heat is simply vented in current test rigs, but in a working model it can be used to produce steam to power generators. That's specifically for tokamaks, but I would guess the process is similar for stellarators.
mozumder 9y ago
So, assuming these work great.. what are the next steps to get fusion energy production? Are there fundamental limits that prevent these designs from producing a commercially profitable neighborhood reactor for, say $1 million? Actually, what's the smallest scale possible for these stellerators? Can one be produced table-top sized, to say, power a ship or train or even a car? So many questions...
- vilhelm_s 9y ago
  The smallest scale is basically the same as for tokamaks (the advantage is that you can operate a stellarator continuously, while a tokamak is pulsed which may be less convenient for power generation). The scale is mostly limited by magnetic field strength. With ordinary superconducting magnets they get pretty big (the planned ITER reactor will weigh 5,116 tonnes). Some people say that new high-temperature superconductors will enable stronger magnets and hence smaller reactors (http://news.mit.edu/2017/brandon-sorbom-designing-fusion-future-0123 http://news.mit.edu/2017/brandon-sorbom-designing-fusion-fut...).
  - mozumder 9y ago
    looking more into this, it looks like the minimum size limit is the wall that absorbs the free neutrons from the De-Tr reactions. It looks like it'll always be some minimum size due to the energy of the released neutrons.
phkahler 9y ago
And just the other day we had a link here where a retired physicist was saying fusion is not likely to work, and if it does it will produce radioactive waste much like fission. I propose we make a reactor large enough to use gravitational confinement and get the energy out via electromagnetic radiation. We could make it safe by having it operate in vacuum at a safe distance from the earth.
- mschuster91 9y ago
  > We could make it safe by having it operate in vacuum at a safe distance from the earth. And if the thing happens to be rotated even by a milli-arc, for example due to asteroid strike or a simple software error, the receiving area will be fried by microwave. Or hackers might want to introduce a deliberate rotation to use it as an orbital based frying weapon. No thanks, that's way too risky.
  - bicubic 9y ago
    He's talking about the sun. We already have a giant fusion reactor that we're not using.
    - dandelany 9y ago
      "Not using"?! Literally all of the energy we consume on earth, except the radioactive material used in our nuclear plants, is a byproduct of said fusion reactor :)
      - castis 9y ago
        And it's reactors all the way down, mate! That radioactive material was created by an ancestor of our current fusion reactor.
      - ygra 9y ago
        Geothermal isn't :)
janemanos 9y ago
Back in the sixties some scientist said "Fusion is ready in 20 years", then in the eighties some others said it again, and in the 2000's the next ones... but hey, I don't care how long it will take as long as humankind strives for such stuff I'm fine
twic 9y ago
Meanwhile, in boring-shaped fusion reactor news, boringly-named Tokamak Energy switched on their new reactor, the ST40, today: http://www.world-nuclear-news.org/NN-Tokamak-Energy-turns-on-ST40-fusion-reactor-28041701.html http://www.world-nuclear-news.org/NN-Tokamak-Energy-turns-on... They only switched it on for a 'glow discharge test', but hey: https://www.youtube.com/watch?v=YNrhTYhUXJc https://www.youtube.com/watch?v=YNrhTYhUXJc Reactor teardown, sort of: https://www.youtube.com/watch?v=jRyUWOUk_48 https://www.youtube.com/watch?v=jRyUWOUk_48
- boznz 9y ago
  Thanks for the links

122 points by clon 9y ago

mandelken 9y ago

only 10 years too late..

Gravityloss 9y ago
The earlier, the better. Can someone say at what point we should stop trying?
- rb1 9y ago
  The point when the black line on the graph goes below 0 http://i.imgur.com/sjH5r.jpg http://i.imgur.com/sjH5r.jpg (from: https://hardware.slashdot.org/story/12/04/11/0435231/mit-fusion-researchers-answer-your-questions https://hardware.slashdot.org/story/12/04/11/0435231/mit-fus...)
  - nomercy400 9y ago
    That only explains why the Wendelstein 7-X isn't being made in the US.
Cerium 9y ago
The best time to plant a tree was 20 years ago. The second best time is today.
DesiLurker 9y ago
my prediction is we'll have fusion net positive within a decade of when alternative energy's growth is significant enough to show up in fossil fuel economy's future projection. oh and no its not too late. if you have cheap and plentiful energy from fusion you can take on massive geoengineering projects to reverse global warming. its a whole another ballgame!
- zlynx 9y ago
  But where are you putting the waste heat from everybody's personal Mr. Fusion reactor? Just imagine if everybody on Earth has a personal, nearly free 10 megawatt generator. Flying cars. Laser weapons. Direct desalination of seawater in coastal cities. Stomping around in powered exoskeleton suits. Anyway, it would be awesome. But where do we put all the heat?
  - DesiLurker 9y ago
    you are right, Waste heat would be a problem because the only way you can dissipate it is by radiation. but that would become a problem much much farther out. I mean we are talking 100+ billions people. Also, if you have plentiful energy you can build way cheaper orbital launch tech. translation you are not bound to earths gravity well anymore. So its not too far fetched to imagine living in space habitats (forget mars that just good for gravity). those will be much better at dissipating waste heat (volume/surface area thing). Like I said its a whole another ballgame.

mrfusion 9y ago

What's the next phase? When does it start? (I don't know if there's a problem with my reading comprehension or what?)

clon 9y ago
From the source: In preparation for the next operation phase (OP 1.2a), which is scheduled to start in late summer of this year, the limiter structures have been replaced by a test divertor and all graphite tiles on the baffles and wall protection elements have been installed. This will allow the use of more heating power and access to the required magnetic field configurations.
ZenoArrow 9y ago
There's no specific date mentioned, but the PDF does mention 'late summer' of this year. Looks like they're about halfway along with preparing the graphite tiles for the next phase (4500 out of 8000).

colonelxc 9y ago

Home page for the project, which provides some higher level details: http://www.ipp.mpg.de/w7x http://www.ipp.mpg.de/w7x

shaqbert 9y ago

Wendelstein 7-x is really not fusion research, but plasma physics research. At the energy/temperature levels and magnetic field strength this machine is operating, plasma is showing all kinds of undesirable behavior, such as turbulence, radial forces... a little bit like the storms on Jupiter. This imposes many challenges, because as soon as the plasma escapes the magnetic field and touches the vessel, it rapidly cools - ending any potential fusion. Wendelstein's goal is to find out the viability of the stellarator concept, to see if it could be on par with the Tokamak concept, which so far have shown a better ratio of energy invested and energy won back, but come with their own bag of problems. What the folks at Wendelstein are doing is a step by step verification of some of the hypothesis. There is this excellent 3h podcast with the scientific leader of Wendelstein [0], unfortunately it is in German. It is fascinating to hear their story on how they build this ultra complex piece of kit. The current change is the shielding of the vessel, which now permits higher energy levels and longer runs. Their long term goal is to operate at 100m K for 30 min. Regarding the "when we should stop trying" and "it is 30 years out" adage: There has been great progress made in improving the ratio of energy invested and energy won back, the G-factor. Right now no fusion reactor is crossing the G > 1 limit. But Iter would be design to yield about G = 5. Newer designs using high temperature superconductors could even yield G > 10 with a smaller footprint. For more on the current state of fusion research, this video [1] from MIT is fantastic, albeit 1h long. [0]: http://alternativlos.org/36/ http://alternativlos.org/36/ [1]: https://youtu.be/L0KuAx1COEk?t=37m23s https://youtu.be/L0KuAx1COEk?t=37m23s

sandworm101 9y ago
But how much of that G > 1 energy has ever been harvested? I get the impression that very little is being done in regards to extracting energy from a sustained fusion reaction. We can't put solar panels in there, nor can I see how one would extract heat given the cooling needs of the magnets. Is there some sort of medium that we can use to pipe heat energy out of this plasma without destroying it?
- PhasmaFelis 9y ago
  > But how much of that G > 1 energy has ever been harvested? None, because we haven't achieved G > 1 yet. :) Per https://physics.stackexchange.com/questions/70209/how-is-energy-extracted-from-fusion https://physics.stackexchange.com/questions/70209/how-is-ene..., hydrogen fusion produces helium and neutrons; neutrons are unaffected by magnetic fields, so they escape confinement and impact the reactor walls, heating them. The heat is simply vented in current test rigs, but in a working model it can be used to produce steam to power generators. That's specifically for tokamaks, but I would guess the process is similar for stellarators.

mozumder 9y ago

So, assuming these work great.. what are the next steps to get fusion energy production? Are there fundamental limits that prevent these designs from producing a commercially profitable neighborhood reactor for, say $1 million? Actually, what's the smallest scale possible for these stellerators? Can one be produced table-top sized, to say, power a ship or train or even a car? So many questions...

vilhelm_s 9y ago
The smallest scale is basically the same as for tokamaks (the advantage is that you can operate a stellarator continuously, while a tokamak is pulsed which may be less convenient for power generation). The scale is mostly limited by magnetic field strength. With ordinary superconducting magnets they get pretty big (the planned ITER reactor will weigh 5,116 tonnes). Some people say that new high-temperature superconductors will enable stronger magnets and hence smaller reactors (http://news.mit.edu/2017/brandon-sorbom-designing-fusion-future-0123 http://news.mit.edu/2017/brandon-sorbom-designing-fusion-fut...).
- mozumder 9y ago
  looking more into this, it looks like the minimum size limit is the wall that absorbs the free neutrons from the De-Tr reactions. It looks like it'll always be some minimum size due to the energy of the released neutrons.

phkahler 9y ago

And just the other day we had a link here where a retired physicist was saying fusion is not likely to work, and if it does it will produce radioactive waste much like fission. I propose we make a reactor large enough to use gravitational confinement and get the energy out via electromagnetic radiation. We could make it safe by having it operate in vacuum at a safe distance from the earth.

mschuster91 9y ago
> We could make it safe by having it operate in vacuum at a safe distance from the earth. And if the thing happens to be rotated even by a milli-arc, for example due to asteroid strike or a simple software error, the receiving area will be fried by microwave. Or hackers might want to introduce a deliberate rotation to use it as an orbital based frying weapon. No thanks, that's way too risky.
- bicubic 9y ago
  He's talking about the sun. We already have a giant fusion reactor that we're not using.
  - dandelany 9y ago
    "Not using"?! Literally all of the energy we consume on earth, except the radioactive material used in our nuclear plants, is a byproduct of said fusion reactor :)
    - castis 9y ago
      And it's reactors all the way down, mate! That radioactive material was created by an ancestor of our current fusion reactor.
    - ygra 9y ago
      Geothermal isn't :)

janemanos 9y ago

Back in the sixties some scientist said "Fusion is ready in 20 years", then in the eighties some others said it again, and in the 2000's the next ones... but hey, I don't care how long it will take as long as humankind strives for such stuff I'm fine

twic 9y ago

Meanwhile, in boring-shaped fusion reactor news, boringly-named Tokamak Energy switched on their new reactor, the ST40, today: http://www.world-nuclear-news.org/NN-Tokamak-Energy-turns-on-ST40-fusion-reactor-28041701.html http://www.world-nuclear-news.org/NN-Tokamak-Energy-turns-on... They only switched it on for a 'glow discharge test', but hey: https://www.youtube.com/watch?v=YNrhTYhUXJc https://www.youtube.com/watch?v=YNrhTYhUXJc Reactor teardown, sort of: https://www.youtube.com/watch?v=jRyUWOUk_48 https://www.youtube.com/watch?v=jRyUWOUk_48

boznz 9y ago
Thanks for the links