3 ms·

"Current [fusion] reactors are approximately the size of a building" I was under the impression there isn't a fusion reactor of any size anywhere yet, am I wro

"Current [fusion] reactors are approximately the size of a building" I was under the impression there isn't a fusion reactor of any size anywhere yet, am I wrong?

ryanwaggoner 7y ago
There are many fusion reactors, just none that produce more energy than they consume. Barring some random research breakthrough by a small team somewhere, ITER is probably the best bet for reaching positive net energy first: https://en.m.wikipedia.org/wiki/ITER https://en.m.wikipedia.org/wiki/ITER
- ben_w 7y ago
  Indeed. I believe the smallest — most hobbyist fusors — are about the size of a suitcase.
- XaspR8d 7y ago
  Yeah, in fact many folks have created DIY fusors in their garages. Just hook any sort of energy harnessing device onto that and you can claim you've got a fusion reactor too! https://makezine.com/projects/make-36-boards/nuclear-fusor/ https://makezine.com/projects/make-36-boards/nuclear-fusor/
willis936 7y ago
They may be referring to W7-X. The lower the aspect ratio of stellarators, the larger the major radius is. This makes a bigger, more expensive machine, but really blows the doors wide open on the largest engineering challenges (high neutron flux, high heat flux materials).
- _Microft 7y ago
  W7-X is this by the way: https://en.wikipedia.org/wiki/Wendelstein_7-X https://en.wikipedia.org/wiki/Wendelstein_7-X
jussij 7y ago
There are several fusion reactors currently in existence and operational as of this day. The problem is none of those reactors produce more energy than they consume.
- jtbayly 7y ago
  Meaning they don't work. Meaning a "reactor" as we think of it—ie one accomplishing it's purpose of power generation—doesn't exist.
  - fulafel 7y ago
    Nuclear reactors aren't necessarily used for power generation. The other applications of nuclear reactors are for example producing interesting elements or isotoopes, and irradiating things like cancer patients and physics experiments. There's are also bioreactors and chemical reactors. It seems to me the term reactor is just used for a device that induces reactions.
  - egdod 7y ago
    The reactors work in that they produce measurable fusion reactions. They only don’t work in practical terms of being a power plant.
    - jtbayly 7y ago
      Yeah. That's exactly what I said. They don't work for what we intend to accomplish with them.
      - egdod 7y ago
        No, you said it doesn’t work as a reactor. It does. The definition of “reactor” doesn’t require generating net positive power.
- willis936 7y ago
  Incorrect. The experiments, largely, are not failures. The confinement devices are made to perform science. A fusion reactor power plant is expensive and it is much cheaper to design a reactor that works then to make a bunch of full-scale reactors that don’t. Also finding 10 billion dollars is hard. Most of these devices use hydrogren most of the time, meaning the cross section of fusion even in high temperatures and densities will be low. If the goal of these devices was fusion energy they would all be using deuterium, at the very least. The fields of plasma physics and materials have progressed to the point where a future reactor likely wouldn’t be a failure. Just look at W7-X and (in 10 years) ITER. Q=10 operation will likely be a very stressful test on ITER and it will likely only happen towards the end of its life (2035). Q=1 shots should be pretty early into tritium operation.
juliangoldsmith 7y ago
To add to what others have said, you can build a fusor [0] that sits on a tabletop. It just consumes energy, rather than producing it. 0: https://en.wikipedia.org/wiki/Fusor https://en.wikipedia.org/wiki/Fusor

"Current [fusion] reactors are approximately the size of a building" I was under the impression there isn't a fusion reactor of any size anywhere yet, am I wrong?

ryanwaggoner 7y ago

There are many fusion reactors, just none that produce more energy than they consume. Barring some random research breakthrough by a small team somewhere, ITER is probably the best bet for reaching positive net energy first: https://en.m.wikipedia.org/wiki/ITER https://en.m.wikipedia.org/wiki/ITER

ben_w 7y ago
Indeed. I believe the smallest — most hobbyist fusors — are about the size of a suitcase.
XaspR8d 7y ago
Yeah, in fact many folks have created DIY fusors in their garages. Just hook any sort of energy harnessing device onto that and you can claim you've got a fusion reactor too! https://makezine.com/projects/make-36-boards/nuclear-fusor/ https://makezine.com/projects/make-36-boards/nuclear-fusor/

willis936 7y ago

They may be referring to W7-X. The lower the aspect ratio of stellarators, the larger the major radius is. This makes a bigger, more expensive machine, but really blows the doors wide open on the largest engineering challenges (high neutron flux, high heat flux materials).

_Microft 7y ago
W7-X is this by the way: https://en.wikipedia.org/wiki/Wendelstein_7-X https://en.wikipedia.org/wiki/Wendelstein_7-X

jussij 7y ago

There are several fusion reactors currently in existence and operational as of this day. The problem is none of those reactors produce more energy than they consume.

jtbayly 7y ago
Meaning they don't work. Meaning a "reactor" as we think of it—ie one accomplishing it's purpose of power generation—doesn't exist.
- fulafel 7y ago
  Nuclear reactors aren't necessarily used for power generation. The other applications of nuclear reactors are for example producing interesting elements or isotoopes, and irradiating things like cancer patients and physics experiments. There's are also bioreactors and chemical reactors. It seems to me the term reactor is just used for a device that induces reactions.
- egdod 7y ago
  The reactors work in that they produce measurable fusion reactions. They only don’t work in practical terms of being a power plant.
  - jtbayly 7y ago
    Yeah. That's exactly what I said. They don't work for what we intend to accomplish with them.
    - egdod 7y ago
      No, you said it doesn’t work as a reactor. It does. The definition of “reactor” doesn’t require generating net positive power.
willis936 7y ago
Incorrect. The experiments, largely, are not failures. The confinement devices are made to perform science. A fusion reactor power plant is expensive and it is much cheaper to design a reactor that works then to make a bunch of full-scale reactors that don’t. Also finding 10 billion dollars is hard. Most of these devices use hydrogren most of the time, meaning the cross section of fusion even in high temperatures and densities will be low. If the goal of these devices was fusion energy they would all be using deuterium, at the very least. The fields of plasma physics and materials have progressed to the point where a future reactor likely wouldn’t be a failure. Just look at W7-X and (in 10 years) ITER. Q=10 operation will likely be a very stressful test on ITER and it will likely only happen towards the end of its life (2035). Q=1 shots should be pretty early into tritium operation.

juliangoldsmith 7y ago

To add to what others have said, you can build a fusor [0] that sits on a tabletop. It just consumes energy, rather than producing it. 0: https://en.wikipedia.org/wiki/Fusor https://en.wikipedia.org/wiki/Fusor