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Proxima Fusion looks to take stellarators commercial
- santiagobasulto 3y ago$7m doesn’t seem much for such a challenging project. How close are they to make this a reality?
- sigmoid10 3y agoNot close. This amount of money will get you some theoretical modelling at best, which is still nice because stellarators are infinitely more complex than tokamaks. The real hope here is that they might solve the plasma instability problem of tokamaks, but the full picture isn't out yet. In any case, we're very far from a commercial stellarator.
- mpweiher 3y agoEr, they've solved the instability problem of tokamaks. They've already run it for 8 minutes, target is 30 and there don't seem to be any fundamental hurdles, just stuff to do to get there. https://www.ipp.mpg.de/5322229/01_23?c=5322195 https://www.ipp.mpg.de/5322229/01_23?c=5322195
- sigmoid10 3y agoNo they haven't. The thing is you need to keep it hot enough and confine it long enough to produce a Q factor large enough for an economically practicable application. We are like one or two orders of magnitude away from that. No magnetic confinement scheme has even reached Q>1 so far, so we're a long way from any useful power plant design.
- willis936 3y agoIndeed it's not. It's a similar level that Type One has received for a demonstration turn of a coil.
- otikik 3y agoIt is "peanuts". If that's the kind of investment it would take to make this a reality everyone and their aunt would have one.
- pgeorgi 3y ago(Some in) the Greifswald team seem to estimate that it takes ~€20bn for a commercial deployment based on Wendelstein 7-X (according to a blogger who went there to ask: https://blog.fefe.de/?ts=9a9561ab https://blog.fefe.de/?ts=9a9561ab)
- doctorhandshake 3y agoStellarators are one of those things where the visual complexity tells some basic part of my brain that 'this can't be the real thing'. Simplicity bias, I guess.
- phkx 3y agoYou can get a free guided tour at the Greifswald site of the IPP in the north of Germany to convince yourself of the physical reality. https://www.ipp.mpg.de/visitors https://www.ipp.mpg.de/visitors
- doctorhandshake 3y agoMan that sounds cool. To clarify, I meant “that looks too complex to be the ‘right’ answer”.
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- phkx 3y agoGot it. Yeah, some intuition would make you think that the problem is somehow symmetrical, since other electromagnetic systems don’t have this ‚organic‘ kind of shape.
- pgeorgi 3y agoSymmetrical except for gravity that always points downwards. I wonder if it's easier to pull off fusion in a (close to) zero gravity environment because the plasma doesn't budge by other effects than the container's.
- doctorhandshake 3y agoI can only imagine taking one factor out can’t hurt
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- Y_Y 3y agoTheir "goal" is an order of magnitude improvement on existing stellarators, that sounds to me like it will want billions rather than millions. It's also doesn't seem to meet the "triple product Lawson criterion" for useful fusion (achieved recently at NIF, expected for ITER). This is cool, but I'm always skeptical of the viability of fusion startups. I won't name names, but there's already a couple out there that seem to me to be vapourware but are dragging in big funding based on the dream of fusion.
- boxed 3y agoNIF didn't have anything even remotely practical though. The energy loss in the lasers alone is game over.
- jmyeet 3y agoI fully support more research into commercial fusion power eneration. I really hope it becomes economical. That being said, I'm not convinced this will ever happen for these reasons: 1. Energy loss from neutron loss. So-called "aneutronic fusion" seeks to avoid this problem but requires rare fuels (eg He-3), which kind of defeats the point. Also, it's not neutron free. It's just fewer neutrons; 2. Container destruction from neutrons (ie "neutron embrittlement"); and 3. A superheated plasma (in either a tokamak or stellerator) is fundamentally a turbulent fluid. This is inherently unstable. Any imperfection in the containment could result in significant container damage. Fusion works for stars because fusion is relatively slow (on a per-unit mass basis, which is why stars can live billions or evne trillions of years) and they have gravity for neutron containment. More on the difference to tokamaks [1]. [1]: https://www.sciencedirect.com/science/article/pii/S2468080X16300322 https://www.sciencedirect.com/science/article/pii/S2468080X1...
- willis936 3y ago>This is inherently unstable. Any imperfection in the containment could result in significant container damage. This is a misunderstanding that conflates multiple concepts: instabilities from toroidal plasma current (unnecessary in stellarators) and edge turbulence (lower confinement time). W7-X has done 30 second shots and are working their way to 30 minute shots. It is their control that has terminated their shots, not the plasma.
- jmyeet 3y agoYou're trying to contain something at ~100 million degrees when the result of that process is destroying the container. It's not an exaggeration to say the engineering challenges are... significant.
- pshirshov 3y agoOnce, when I was a schoolboy, I walked along this thingy: https://www.inp.nsk.su/~dep_plasma/img/GOL3.jpg https://www.inp.nsk.su/~dep_plasma/img/GOL3.jpg and the guide told us that a couple of millions USD would let them build a working commercial fusion machine. I've heard many news like that since then, so I'm extremely skeptic.
- anonuser123456 3y agoAny DT fusion proposal that doesn’t start with how they plan to breed and capture tritium is a dead end.
- denton-scratch 3y agoTFA doesn't say what a "stellarator" is. https://en.wikipedia.org/wiki/Stellarator https://en.wikipedia.org/wiki/Stellarator
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