9 ms·
Spherical tokamak achieves crucial plasma temperatures
- fandorin 4y agoif you want to understand fusion and what the heck tokamak is - I can highly recommend Lex Friedman conversation with Dennis Whyte [1]. It’s a great source of info not only about the fusion energy - Dennis describes so much more there! Amazing guy. [1] https://open.spotify.com/episode/5X1TXNQ9zIo5PGJe80xtpv?si=ZCb0TK_rTp-C4usEoYjrNQ https://open.spotify.com/episode/5X1TXNQ9zIo5PGJe80xtpv?si=Z...
- stefantalpalaru 4y ago> if you want to understand fusion https://thebulletin.org/2017/04/fusion-reactors-not-what-theyre-cracked-up-to-be/ https://thebulletin.org/2017/04/fusion-reactors-not-what-the...
- gus_massa 4y agoI had to search it: https://en.wikipedia.org/wiki/Spherical_tokamak https://en.wikipedia.org/wiki/Spherical_tokamak > A traditional tokamak has a toroidal confinement area that gives it an overall shape similar to a donut, complete with a large hole in the middle. The spherical tokamak reduces the size of the hole as much as possible, resulting in a plasma shape that is almost spherical, often compared with a cored apple.
- hinkley 4y agoIs it possible I’ve only seen pictures of a spherical tokamak? All the renditions or pictures I’ve seen had a core pillar that was 1/8 or 1/10 the height of the chamber. Which has me wondering if there’s another tokamak out there with a much larger inner diameter. The stellerator for instance is more traditionally toroidal.
- TaylorAlexander 4y agoHere is a cutaway drawing of a toroidal tokamak for reference. It still has a relatively small center pillar. https://commons.wikimedia.org/wiki/File:JET_cutaway_drawing_1980.jpg https://commons.wikimedia.org/wiki/File:JET_cutaway_drawing_...
- ianburrell 4y agoThat is because it was discovered that the D-shape tokamak was more stable than toroidal ones. All of the major ones since the 80s have used the D-shape. The D-shaped "advanced tokamaks" and spherical tokamaks are similar shape but the spherical has smaller center hole. That is the most efficient but it is harder to build. The center hole is the most confined space in giant ITER.
- dejv 4y agoThey used to produce great Youtube channel: https://www.youtube.com/@tokamakenergy6400 https://www.youtube.com/@tokamakenergy6400
- robocat 4y agoOne video that shows two guys inside the tokamak, installing a diverter, which gives you an idea of the internal dimensions of the toroid - 10 minutes into https://www.youtube.com/watch?v=YkkeCjgrG-0 https://www.youtube.com/watch?v=YkkeCjgrG-0
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- xqcgrek2 4y agoMarketing hype. This is very far from being useful.
- lallysingh 4y agoNobody said it would be. Did your RTFA? It's just a milestone crossed.
- Ygg2 4y agoWhen asked about usefulness of electricity Faraday replied: "What use is a newborn baby?"
- thriftwy 4y agoTokamak cannot be spherical since To stand for Toroidal. How about Sphekamak?
- adastra22 4y agoIt is toroidal, just compressed so small that the packaging is spherical.
- sbierwagen 4y ago"Spheromak" is already taken by a very different reactor design: https://en.wikipedia.org/wiki/Spheromak https://en.wikipedia.org/wiki/Spheromak
- omneity 4y agoIt doesn't seem to be so fundamentally different. Quoting the Wiki: Spherical tokamak, essentially a spheromak formed around a central conductor/magnet
- wiml 4y agoThere's already something called a "spheromak" (I'm not sure what the difference is except they've been around for a while and apparently they're not good prospects for energy production — they have other scientific uses)
- RangerScience 4y agoOne thing I’ve never figured out about fusion - how do you get the heat out and turned into electricity? (Presumably, water to steam then turbines, like everything, but how do you get the heat out from the reaction?)
- jamiek88 4y agoThat's kinda on the 'we'll figure it out later' track. Materials are being investigated that can withstand the heat and neutron bombardment to attach a steam turbine the old fashioned way. But we ain't there yet, not without having to constantly change the 'walls'. > Most of the energy produced inside a fusion reactor is emitted in the form of neutrons, which heat a material surrounding the fusing plasma, called a blanket. In a power-producing plant, that heated blanket would in turn be used to drive a generating turbine
- DennisP 4y agoZap Energy is using a "waterfall" of molten lead-lithium for its inner wall. They're planning to attempt net power this year.
- Tuna-Fish 4y agoThe simplest answer that's part of the plan for most DT reactors is "as neutrons". The fraction of the energy that is retained as velocity of particles with a charge vs that is lost as the velocity of neutrons turns out to be conveniently just about where you'd want it to be. So, to capture the energy you need to surround your reactor with something that effectively converts fast neutrons to heat, such as a blanket of molten lithium, which you then use as a heat source. Lithium is proposed because it would also breed the necessary tritium.
- aziaziazi 4y agoDoes that mean you need to “feed” with new lithium regularly ? Any idea on the frequency, like lithium gram*watt produced ?
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- trebligdivad 4y agoI love the picture; HUGE bus bars at the top; stuff held together with random metal framing, and a couple of dangling UK 13A plugs!
- tyingq 4y agoThat L-shaped piece of t-slot aluminum that's dead center in the picture looks especially janky. Like sort of a quick and dirty friction fit brace.
- lostlogin 4y agoIt looks like the inside of The Millennium Falcon, but with more duct tape.
- baremetal 4y agoif you have ever worked in research science you would know this is common. especially government research science "good enough for government work"
- ajford 4y agoYup! Worked at a gov't funded radio telescope and this is just the right level of jank for scientific progress. Complete with random bits of aluminum extrusion for bracing, random leftover cables no one's cleaned up yet, "interim" solutions, and duct tape.
- post-it 4y agoI love the wooden ceiling above.
- fnordpiglet 4y agoThat said the picture of the plasma itself was like the warp core for the enterprise. It’s happening!
- jimmySixDOF 4y ago
- nelox 4y agoThis podcast covers the state of the art, including the spherical tokamak: https://podcasts.apple.com/au/podcast/babbage-from-the-economist/id508376907?i=1000606490881 https://podcasts.apple.com/au/podcast/babbage-from-the-econo...
- charliea0 4y agoI feel like commercial fusion is such a lost cause at this point. For electrical generation, it’s going to have high fixed costs which will likely make it uneconomical for the same reasons fission struggles. The cost of fuel already very low for traditional fission and renewables. I don’t see what advantages it would have over wind, solar, fission, etc.
- lanternfish 4y agoFission is theoretically amazing in many cases, but is hampered by branding problems. If fusion can be marketed as "clean", it gets a comparative advantage.
- Firmwarrior 4y agoAs I understand it, fusion's radioactive contamination and waste is a lot shorter-lived than fission reactors', and there's no chance of a runaway meltdown reaction (not that there's any chance of that with a modern fission reactor either... and fission reactors generate a tiny bit of waste in exchange for free unlimited energy...)
- Andrew_nenakhov 4y agoCleansion.
- trebligdivad 4y agoThat's one of the points of the spherical tokamaks - they're MUCH smaller than the standard tokamaks (I can't remember the numbers but it's vastly smaller). That brings the cost way way down. The modern HTS magnets are also more powerful, even in the Tokamak systems (like CFSs) which again get the size way down - I think it's something like cubed size reduction for doubling magnet strength (?). You'd be right for something of the silly size of ITER.
- hnlmorg 4y agoThat’s because commercial fusion doesn’t exist yet. All new technology isn’t commercially viable when only viewed from the perspective of early prototypes. This is as equally true for consumer hardware as it is for massive scientific endeavours.
- tokamak-teapot 4y agoI feel like they are close to the right shape but haven’t quite got a handle on it.
- danparsonson 4y agoHave you been waiting three years since creating your account, just to make that joke? :-)
- itsthecourier 4y agoI suspect what his geometric suggestion is gonna be
- fnordpiglet 4y agoWith current funding levels for fusion research that’s about the right pace of things
- numbsafari 4y agoDonut go there
- manv1 4y agoTokamaks have been asymptotically approaching viability for a very, very long time. At some point they just have to give up on the design, because it just isn't working. But I suppose as long as there's funding there'll be people trying to get it to work.