Earlier quoted context omitted.
How would you know?
I worked in the nuclear energy area. I also invested personal money into several fusion startups.
Well that'll teach me
Wendelstein 7-X: Gigajoule energy turnover generated for eight minutes
221–230 of 322 posts
Re: Wendelstein 7-X: Gigajoule energy turnover generated for eight minutes
#222[dead]
Re: Wendelstein 7-X: Gigajoule energy turnover generated for eight minutes
#223Question for this knowledgeable group of people: Which fusion start-ups look promising? How does inertial confinement look? Any thoughts on the newly funded start-up Blue Laser Fusion? Any thoughts on one of the older players, TAE? How about Commonwealth? Helion? Others?
I think Helion is most promising for two reasons.
1. Even if the more traditional fusion power plants manage to generate the plasma itself in a device that’s not too expensive (big if) it seems that just the heat exchange mechanism itself would be extremely complicated and expensive. And since they’re thermal power plants you’re limited in where you can put them and how big they must be to be economical.
2. As CO2 emissions come down, I think there will be some focus on thermal power plants contribution to global warming. Helion will still be adding heat to the planet that wasn’t there before, but there will be less heat for a given amount of electric energy. It’s also not going to rely on dumping all that heat in a river. I don’t know if Helion is feasible. But it feels like it’s the only technology that could be feasible.
Re: Wendelstein 7-X: Gigajoule energy turnover generated for eight minutes
#224Earlier quoted context omitted.
> the wendelstein 7x is never going to generate usable electricity What's the reason for that?
You can't jump from idea to production power plant in one step. This is research about the fundamental science involved. What they're doing is incredibly difficult and complex. They have a plasma at millions of degrees mere centimeters from superconductors at near absolute zero. The field geometry and interactions are so complex it brings even current supercomputers to their knees. The device wasn't even possible to…
> idea to an option in door dash
I hear ya. The attention span of a TikTok or less.
Re: Wendelstein 7-X: Gigajoule energy turnover generated for eight minutes
#225Earlier quoted context omitted.
Most of the answers are missing the actual (proposed) mechanism. The energy of the reaction is mostly carried away as high-energy neutrons. So, the way to get energy back is to "capture" those neutrons. Since neutrons are not electrically charged, you can't use them to directly create electricity, so all you're left with is using them for heat. Unfortunately, since they are electrically neutral, they're also relative…
What eventually happens to the excess neutron “waste”? Surely there’s some negative consequence to producing an enormous number of neutrons, no?
All the neutrons that don't get caught by the blanket will usually be caught by the support structure of the reactor, damaging it and making it radioactive. This puts a cap on the maximum lifetime of this type of fusion reactor until significant parts of the structure need to be dismantled and replaced, and stored as highly radioactive waste. As far as I know, current estimates suggest something like a decade - one of the biggest problems with the economics of fusion power plants.
Re: Wendelstein 7-X: Gigajoule energy turnover generated for eight minutes
#226Earlier quoted context omitted.
I'm not that guy, but I can speak to what you're asking. I've followed Wendelstein 7-X for almost a decade. Nuclear fusion occurs at extremely-high temperatures. As you heat your fusion fuel to sufficiently-high temperatures to allow fusion, the matter transitions into a plasma, which is great: plasmas react to electromagnetic fields. As such, a major challenge with achieving viable nuclear fusion is making a vessel…
> Even better is to use the helium3-helium3 reaction, which completely annihilate to produce pure energy as the output (welcome to e=mc^2, enjoy your stay). It doesn't completely annihilate to produce pure energy. It produces helium-4 and two protons. Or you can react helium-3 + deuterium to produce helium-4 and one proton. The point is that helium-4 and protons are easier to shield against than neutrons, don't turn…
You're absolutely right, thank you for the correction. he3-he3 doesn't produce neutrons, which is the major advantage, in addition to the massive energy output.
Here's an interesting link which lists various fusion reactions: https://en.wikipedia.org/wiki/Helium-3#Nuclear_fuel
Re: Wendelstein 7-X: Gigajoule energy turnover generated for eight minutes
#227Earlier quoted context omitted.
Compared to a tokamak, the stellarator bring engineering efficiency while matching performance. Though ideas for the tokamak and the stellarator may have emerged together, the main reason tokamaks were built first is because they COULD be built. Without computer-assisted magnet design, stellarators simply couldn't be properly built; the magnetic geometries are just too complex. In the long run, it's not known stellar…
I understand the theory. I just hope I will live long enough to see a winner in this race. To be honest, I've been interested in the domain for quite a time and I still want to build a fusor or a polywell at some point just to see it glow. Probably won't happen though.
The most difficult parts to obtain will be the power supply and vacuum chamber. Still, there's nothing like garage fusion!
Re: Wendelstein 7-X: Gigajoule energy turnover generated for eight minutes
#228Earlier quoted context omitted.
Most of the answers are missing the actual (proposed) mechanism. The energy of the reaction is mostly carried away as high-energy neutrons. So, the way to get energy back is to "capture" those neutrons. Since neutrons are not electrically charged, you can't use them to directly create electricity, so all you're left with is using them for heat. Unfortunately, since they are electrically neutral, they're also relative…
What is happening in a star to emit useful radiation? I feel I should know that, I probably did but forgot.
Stars rely on gravitation to confine the plasma instead of magnetic fields, and they can reach the energy densities needed for other fusion reactions, typically D+D, which produces less neutrons. Also, there are hundreds of thousands of kilometers between the center of the sun and its outermost layers - neutrons produced in the core will have plenty of time to be absorbed by something else on their way out.
Re: Wendelstein 7-X: Gigajoule energy turnover generated for eight minutes
#229Earlier quoted context omitted.
I'm not that guy, but I can speak to what you're asking. I've followed Wendelstein 7-X for almost a decade. Nuclear fusion occurs at extremely-high temperatures. As you heat your fusion fuel to sufficiently-high temperatures to allow fusion, the matter transitions into a plasma, which is great: plasmas react to electromagnetic fields. As such, a major challenge with achieving viable nuclear fusion is making a vessel…
The terms (not specific to tokamaks) are "toroidal" and "poloidal". https://en.wikipedia.org/wiki/Toroidal_and_poloidal_coordina...
Oops, my bad on the typos. Thanks for the correction.
Re: Wendelstein 7-X: Gigajoule energy turnover generated for eight minutes
#230Earlier quoted context omitted.
It's always fascinating to me that, no matter how many interesting new ways to release lots of energy we develop, we are still stuck with the same method for converting it to electricity: release the energy as heat, use heat to make steam, use steam to drive generator.
Helion is planning to use induction to generate electricity from the fusion reaction's generated magnetic field, IIUC: https://www.helionenergy.com/faq/ (See "How does Helion generate electricity from fusion?" question)
Helion is planning to use a different fusion reaction, one where the bulk of the energy will be coming out as charged particles, not neutrons.
However, D+T fusion is the only type of fusion that we have been able to sustain for any significant amount of time with reasonable energy inputs. What Helion is planning to do is completely unexplored and requires some major scientific advances.