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In extension to this news and the press conference, one thing I am super excited about, is the private SPARC project and the MIT-spinoff Commonwealth Fusion Sys
by ppaattrriicckk 5y ago
In extension to this news and the press conference, one thing I am super excited about, is the private SPARC project and the MIT-spinoff Commonwealth Fusion Systems (CFS). If you don't know about it already, I would highly recommend checking it out (e.g. by searching YouTube for "MIT Sparc Fusion Reactor" for some fairly accessible videos on the theory behind why they should achieve fusion way faster than the current roadmap with ITER and DEMO).
In the press conference just ended, they repeated how exactly the JET reactor worked as predicted by theory. In my layman's understanding, for the exact same reason (seemingly very sound theoretical groundwork), the SPARC reactor should exceed breakeven within the next few years.
From Wiki on CFS:
* Back in September 2021, they built the strongest high-room-temperature superconducting magnet (20 Tesla) suitable for a fusion reactor
* Theory dictates that with stronger magnets, the reactor can be scaled down (with the square/cube, can't remember exactly), and thus cost and time to develop
* Back in November 2021, they raised $1.8 billion from the likes of Bill Gates
https://en.wikipedia.org/wiki/Commonwealth_Fusion_Systems https://en.wikipedia.org/wiki/Commonwealth_Fusion_Systems
Boy, do I think it would be crazy cool if they succeed, even taking twice as long as they've planned! :)
- willis936 5y agoI remember being nervous about CFS not being able to raise its 100 MUSD target a few years ago. I'm very excited for their results.
- moogly 5y ago> Theory dictates that with stronger magnets, the reactor can be scaled down (with the square/cube, can't remember exactly), and thus cost and time to develop OTOH, in a tokamak, the plasma volume (and potential energy output) scales quadratically with the torus' aspect ratio (ratio of major to minus radius), so I'm not sure that tokamak-based fusion really is particularly suitable to miniaturization.
- ppaattrriicckk 5y agoI had no idea, thanks for sharing. Again, I'm very much a layman to this subject, but how does miniaturization necessarily affect that particular aspect ratio? Since it's literally a ratio of two dimensions of the torus, shouldn't this be invariant to the overall size? (Assuming all things being equal, which I have no idea whether holds.)
- Turbots 5y ago
- kuprel 5y agoWouldn't the aspect ratio remain constant as you scale down?
- DennisP 5y agoTokamak output scales with the square of reactor volume but the fourth power of magnetic field strength, so with sufficiently powerful magnets, scaling down the size can be an option.
- beambot 5y agoThis technical deep-dive by Dr. Dennis Whyte goes into the scaling considerations: https://www.youtube.com/watch?v=rY6U4wB-oYM https://www.youtube.com/watch?v=rY6U4wB-oYM TLDR: Tokamak economics scale in size with 1/B^5 -- so doubling the magnet field strength reduces the physical size substantially. This factor dominates other scaling parameters by a substantial margin, and is entirely enabled by high-temperature superconductors. A host of other key fusion parameters also scale beneficially with B^x (for some value of x) -- most of which are discussed in first half the video.
- gloriana 5y agoHowever, you as you scale down, all the radiation damage effects per unit volume or unit surface area increase rapidly causing higher material activation and maintenance cost.
- XorNot 5y agoMiniaturization has never been realistic with tritium fusion anyway due to neutron production - you need several metres of material to stop them, otherwise your reactor is just kicking off radioactive oxygen into the atmosphere.
- px43 5y agoThe insane thing that people should realize about the 20T CFS test back in September was that it was them completing the first of 18 coils, and it performed incredibly well. The secret sauce is better high temperature superconductors, and the ridiculous magnets you can build with them. They're pretty much putting these coils together as quickly as they can accumulate the HTSC wiring, and once they have all 18, they basically just need to put them all in a ring and light it up, and in theory they'll be generating over 10x the amount of power that they're putting into it. This is the kind of tangible progress that gets me really excited. I wish there was a tracker on the CFS site to see how many coils they've completed so far, similar to tracking the progress of the JWST. Last I checked they were estimating completion around 2025, and at this pace that actually seems reasonable.
- spyder 5y agoyea, just "draw the rest of the owl" :-D
- elihu 5y agoReBCO tape is the specific high-temperature superconducting material they're using. Another important material is FLiBe, which is a liquid that I think absorbs the energy from the fusion reactor. I don't really understand the properties that make it particularly well suited to the task, but I gather it's important. https://en.wikipedia.org/wiki/Rare-earth_barium_copper_oxide https://en.wikipedia.org/wiki/Rare-earth_barium_copper_oxide https://en.wikipedia.org/wiki/FLiBe https://en.wikipedia.org/wiki/FLiBe
- javajosh 5y agoAccording to the article, FLiBe has the same heat capacity of water, but a boiling point over 14x higher (1430 °C according to the article). Melting point is 359 °C, 3.5x higher. I will speculate that its basically used as a water coolant with the phase shifts shifted up and out. I bet the heat exchangers are exotic, too, having to operate at such high temps! In fact I'd expect to see a pretty sophisticated cascade of exchangers.
- 5y ago
- fiftyfifty 5y agoThere are certainly some exciting projects happening in the fusion world coming up. It seems likely we will start seeing much higher energy outputs, I think for SPARC they are predicting >10x the energy produced as what it will consume (Q > 10). My biggest question is with the crazy temperatures involved will we ever see one of these things able to run for hours at a time? With SPARC they are shooting for 10 second bursts, so that would double this breakthrough for the JET reactor. Even with the magnetic containment there are components in there exposed to millions of degrees Celsius right? That leaves us with some significant material science problems to solve.
- DennisP 5y agoTemperature is high but total heat isn't remarkable. The atoms are moving very fast but there aren't many of them.
- 2OEH8eoCRo0 5y agoI'd love to work at CFS. Cambridge, MA is right down the road from me and there is no greater cause right now than fusion energy in my opinion.
- hattmall 5y agoWhy though, we already have Nuclear energy, we could easily build enough that it could power the world's energy needs. The issue is storage, until we have a revolutionary storage solution very little will change with fossil fuel usage.
- twarge 5y agoHowever! fusion plants are much larger than fission cores, and the neutrons are an order of magnitude more energetic, so you wind up with both way more mass and way higher activation.
- MadcapJake 5y agoStorage is an issue for the other renewables due to intermittent peak power. Fusion should be able to operate like a traditional power station.
- foobarbecue 5y agoDid you mean power storage or waste storage?
- RivieraKid 5y agoI think at this point it's very likely that CFS will succeed. But economics could be a problem, which is why I'm more excited about Helion or ZAP.
- avidphantasm 5y agoAt this point, I think fusion has the best chance of saving us from ourselves wrt to climate change, so long as the unforeseen consequences aren’t too bad.
- kadoban 5y agoIt doesn't seem like it's quick enough. We're, at minimum, decades away from it even being built out commonly, and to _really_ save ourselves we should have already replaced a substantial portion of the world's energy generation decades ago.
- NateEag 5y agoSure, it may be too little, too late. You don't know that until the failure is complete, though, and "it may fail" is a terrible reason to not try the best shots we have.
- kadoban 5y agoI mean, it _will_ fail at stopping global warming, there's no "may" about it. It will probably have other positive effects though. I'm very onboard for any potential fusion power generation, I just don't think it has any hope of saving us from global warming.
- nielsbot 5y agoCan we use it to put the CO2 back in the ground? I guess there are some irreversible effects once warming reaches a certain threshold however.
- avidphantasm 5y agoYes, this is part of what would need to happen: using a super abundance of essentially carbon-free energy to do geo-engineering on a massive scale (including artificial carbon sequestration).
- dkbrk 5y ago> Theory dictates that with stronger magnets, the reactor can be scaled down (with the square/cube, can't remember exactly), and thus cost and time to develop Here's the quick summary: B: magnetic field strength R: length scale Fusion rate ∝ (plasma pressure)^2 ∝ B^4 Energy gain (Q) ∝ R^1.3 B^3 Power density ∝ R B^4 Cost ∝ R^3 So, say for example you're targeting a fixed Q. Doubling the magnetic field strength results in R1 = R0 / 2^(3/1.3) = 0.2 R0. And 0.2 R0 translates to 1/(0.2)^3 = 0.008 = 0.8% the cost. The scaling is absolutely insane, and a stronger magnetic field has other advantages (such as making plasma instability far less of a concern), though structural loads can be an issue (that, at least is a relatively straightforward engineering problem). If you take 12T for ITER and 20T for SPARC, that's not actually 2x, it's 1.67, which translates to 30% the size and 3% the cost (and time). It should also be noted that this is just rough, order-of magnitude estimation, but it should be broadly accurate. For a more detailed explanation: https://youtu.be/KkpqA8yG9T4 https://youtu.be/KkpqA8yG9T4
- drjesusphd 5y agoTo be fair, the main reason instabilities are less of a concern is wrapped up in that B^4 scaling.
- dkbrk 5y agoI understand there's a bit more to it than that. Here's the section in Professor Whyte's talk: https://youtu.be/KkpqA8yG9T4?t=2215 https://youtu.be/KkpqA8yG9T4?t=2215 > It's even more subtle than that, in fact this is really one of the things we've studies at MIT, is that there's other things that come in terms of benefits, particularly when you make the magnetic field very high, it basically starts to tame, just all of the whole suite of plasma instabilities that exist.
- lnxg33k1 5y ago>> Back in November 2021, they raised $1.8 billion from the likes of Bill Gates <joke> I guess windows will be resetting the house energy provider on each update soon </Joke>
- deleted 5y ago[deleted]
- TheProbes 5y agoThere's no such thing as a room temperature super-conducting magnet. You are talking about "high temperature" magnets, which are YBCO tape magnets. High temperature, in this case, means about -290 degrees F. The next breakthrough that will come will be YBCO powder-in-tube wires, that will allow much stronger fields than currently. They'll be here within a decade, probably much less, as working prototypes exist now.
- extropy 5y agoAnything that is warmer than liquid nitrogen is room temp for scientists. It's easy to produce, handling is well understood and cheap.
- childintime 5y ago> -290 degrees F -273.15°C == −459.67°F
- ricardobeat 5y agoI think they were referring to the boiling point of liquid nitrogen, at around -196°C, not being cooled by nitrogen being what makes them "high temperature".
- ppaattrriicckk 5y agoYeah, you're right. That was a typo and now I can't correct it. I'm not sure what "high room temperature" would even entail :)
- londons_explore 5y agoPrivate companies have a big incentive to share the good news and hide the bad news. What are the chances these guys have a pile of problems they can't solve with their approach, but rather than trying to approach it from another direction like an engineer would, instead they continue development because collecting more investor cash while the investors are unaware of the showstoppers is good employment.