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Revamped German stellarator should run longer, hotter and compete with tokamaks

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Re: Revamped German stellarator should run longer, hotter and compete with tokamaks

#21

Post by baking »

dleslie wrote: post #6

Forgive my ignorance; what with all the effort made to isolate the exceedingly hot plasma from connecting with any surface, what are the plans to extract the heat in order to generate power?

For Deuterium-Tritium reactions, the easiest to achieve, 80% of the energy is contained in neutrons which pass through the first wall and must be captured in a blanket. The rest of the energy could be carried to the first wall by photons, called radiative cooling, but you can also use divertors that allow the fusion products to escape the plasma carrying away some of the heat.

I think in a stellarator you will need divertors to remove the fusion products because of the continuous operation.

Re: Revamped German stellarator should run longer, hotter and compete with tokamaks

#22

Post by hotpotamus »

wincy wrote: post #2

This has to be the most opaque title I’ve ever seen on Hacker News. For anyone wondering, this is about a potential development in cold fusion reactors.

Others are pointing out that this is (very) hot fusion. But I'd just say that if you know the first thing about fusion, the title is actually very simple, ie, stellarators and tokamaks are competing designs for magnetic confinement fusion. Of course, no one is born knowing anything about nuclear physics, and it's not really a casual subject of conversation, so there might be a lesson here that people could take about writing in domain specific jargon and how inaccessible it is for outsiders.

Re: Revamped German stellarator should run longer, hotter and compete with tokamaks

#23

Post by ak217 »

dleslie wrote: post #6

Forgive my ignorance; what with all the effort made to isolate the exceedingly hot plasma from connecting with any surface, what are the plans to extract the heat in order to generate power?

By capturing neutrons (which, not being charged, escape the magnetic confinement continuously as the reaction goes on) with a moderator blanket which is then cooled with water/steam.

How to keep the blanket from quickly degrading and becoming nuclear waste seems to be an open problem (not too different from what goes on in fission reactors though)

https://en.wikipedia.org/wiki/Fusion_power#Energy_capture

Re: Revamped German stellarator should run longer, hotter and compete with tokamaks

#24

Post by sidkshatriya »

pfdietz wrote: post #11
dleslie wrote: post #6

Forgive my ignorance; what with all the effort made to isolate the exceedingly hot plasma from connecting with any surface, what are the plans to extract the heat in order to generate power?

This would be for DT fusion, so most of the energy would come out as neutrons. And it would face the same showstoppingly bad volumetric power density as tokamaks, because of limits on that energy flow through the surface of the reactor.

> And it would face the same showstoppingly bad volumetric power density as tokamaks, because of limits on that energy flow through the surface of the reactor.

I do think it is worth persevering though. The future of energy is Solar/Wind but Fusion should not be ignored. It is one of Nature's fundamental processes. Mastering fusion could turn out to be useful in ways we cannot possibly fathom at the moment right now.

Re: Revamped German stellarator should run longer, hotter and compete with tokamaks

#25

Post by dathinab »

Someone wrote: post #20
dleslie wrote: post #6

Forgive my ignorance; what with all the effort made to isolate the exceedingly hot plasma from connecting with any surface, what are the plans to extract the heat in order to generate power?

https://www.iter.org/sci/MakingitWork : “The helium nucleus carries an electric charge which will be subject to the magnetic fields of the tokamak and remain confined within the plasma, contributing to its continued heating. However, approximately 80 percent of the energy produced is carried away from the plasma by the neutron which has no electrical charge and is therefore unaffected by magnetic fields. The neutrons…

Makes me wonder if given the increasing value of water this has to change a bit (for reactors not close to shore).

I.e. instead of letting the steam escape into the air after going through a turbine using some mechanism to passively cool/condense it "somehow", reusing _all_ coolant water, only having closed loop(s) (the "inner" cooling loop is often closed anyway for various reasons transferring the heat to an outer loop before its used for anything).

Re: Revamped German stellarator should run longer, hotter and compete with tokamaks

#26

Post by warinukraine »

ak217 wrote: post #23
dleslie wrote: post #6

Forgive my ignorance; what with all the effort made to isolate the exceedingly hot plasma from connecting with any surface, what are the plans to extract the heat in order to generate power?

By capturing neutrons (which, not being charged, escape the magnetic confinement continuously as the reaction goes on) with a moderator blanket which is then cooled with water/steam. How to keep the blanket from quickly degrading and becoming nuclear waste seems to be an open problem (not too different from what goes on in fission reactors though) https://en.wikipedia.org/wiki/Fusion_power#Energy_capture

No post body was provided.

Re: Revamped German stellarator should run longer, hotter and compete with tokamaks

#28

Post by NKosmatos »

Just like COVID helped the mRNA/CRISPR technology evolve and come faster and closer to us, with the potential for many more usages in various diseases, I hope that the ongoing/coming energy crisis will help all nuclear fusion technologies tokamak/stellarator become real. We’re still a few years away from having them in actual power plants and a few decades away from solving our energy problems for every, but I hope we get there sooner than later.

Re: Revamped German stellarator should run longer, hotter and compete with tokamaks

#29

Post by GordonS »

sidkshatriya wrote: post #24
pfdietz wrote: post #11

Earlier quoted context omitted.

This would be for DT fusion, so most of the energy would come out as neutrons. And it would face the same showstoppingly bad volumetric power density as tokamaks, because of limits on that energy flow through the surface of the reactor.

> And it would face the same showstoppingly bad volumetric power density as tokamaks, because of limits on that energy flow through the surface of the reactor. I do think it is worth persevering though. The future of energy is Solar/Wind but Fusion should not be ignored. It is one of Nature's fundamental processes. Mastering fusion could turn out to be useful in ways we cannot possibly fathom at the moment right now.

I agree. If we were able to eventually miniaturise fusion reactors, they would be incredible for space flight. Back on Earth, if they could be made safe enough, maybe we could even use them to run container ships?

Re: Revamped German stellarator should run longer, hotter and compete with tokamaks

#30

Post by EamonnMR »

detritus wrote: post #19
wincy wrote: post #2

This has to be the most opaque title I’ve ever seen on Hacker News. For anyone wondering, this is about a potential development in cold fusion reactors.

More opaque than every nth HN title referring to some cutely-monikered code framework that presses all the wrong mental buttons in those oblivious to its nature? Surely not.

Splark: a new phlinto framework built in blenk.

And the thread is just Blenk fans arguing with Fobl fans.

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