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Major breakthrough on nuclear fusion energy

bbc.co.uk

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Re: Major breakthrough on nuclear fusion energy

#811

Post by elihu »

londons_explore wrote: post #753
javajosh wrote: post #565

Earlier quoted context omitted.

According 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 o…

Higher temperatures in the coolant loop are normally desirable for efficiency. In a heat engine, the hotter the hot side, and cooler the cold side, the more energy you can extract after all. I don't really see why it's important for a fusion reactor though, where efficiency isn't really a concern at this point.

Well, the energy output of the reactor is limited by the amount of energy you can get out, which is limited by how much coolant you can move through it and how much energy the coolant can absorb without boiling/exploding. The MIT SPARC/ARC reactor designs are physically rather small, so it's possible that heat exchange could be the limiting factor in power output of an individual reactor.

Re: Major breakthrough on nuclear fusion energy

#812

Post by nr2x »

mdavis6890 wrote: post #610
nr2x wrote: post #595

Earlier quoted context omitted.

Yes, but every step forward on this path is thrilling. If we crack carbon capture at scale, and unleash fusion, it would change the game for the survival of our species.

Negative. If we want to "change the game for the survival of our species" that would be fission, a super-mature and proven technology that is already widely deployed. As far as "carbon sequestration" - that is just a tree. No R&D required.

I think fission has very good technical merits but the unfortunate reality is it's politically untenable.

Re: Major breakthrough on nuclear fusion energy

#813

Post by nr2x »

immmmmm wrote: post #607
nr2x wrote: post #595

Earlier quoted context omitted.

Yes, but every step forward on this path is thrilling. If we crack carbon capture at scale, and unleash fusion, it would change the game for the survival of our species.

To change the game for the survival of our species (if protecting a species that destroyed 75% of ecosystems as of today is really sth wanted anyway) we might want to protect the other species as well since we rely on them almost entirely for anything relevant to survival. Also I am not sure having ten times more energy would do any good. IPBES reports as well as the literature in relevant conservation journals are r…

Yes fully agree but step one on that path is to stop dumping carbon into the air and oceans.

Re: Major breakthrough on nuclear fusion energy

#814

Post by mannykannot »

GavinMcG wrote: post #797
mannykannot wrote: post #129

Earlier quoted context omitted.

This issue is indeed trivial, but I don't know how, in general, we are going to achieve mutual understanding without establishing an agreed-upon semantics.

It's not possible to fix a particular semantics outside a particular time and context, and certainly not possible to do so in general. Here, as soon as someone recognizes that the amount of energy cited is way higher or lower than would be implied by their own definition, they should 1) identify the difference ("Boil here means 'boil n kettles dry' rather than 'bring n kettles to boil'") and 2) in most cases, avoid t…

Indeed - so it is clear what one should do here, which is to begin by assuming the author is adopting a well-established meaning within the relevant context. For this, we have a couple of clues: one is British English usage, given that this is a press release from a British laboratory, and the other is that there is a meaning in which the calculation works out correctly.

In the light of this, what is your objection to my comment? As far as I can tell, it is in conformance with your numbered principles.

Re: Major breakthrough on nuclear fusion energy

#815

Post by mcswell »

fourseventy wrote: post #535
satronaut wrote: post #519

Earlier quoted context omitted.

an african or european kettle?

Maybe two kettles could boil the water together?

I thought they were these Kettles: https://youtu.be/ieKTU94-BgI

Good at math, but I'm not sure they could boil any water.

Re: Major breakthrough on nuclear fusion energy

#816

Post by mcswell »

khafra wrote: post #182
ambrozk wrote: post #171

Earlier quoted context omitted.

This is a very dumb meme that people use to avoid learning anything about the actual hurdles that are currently being faced by fusion researchers. At some point, fusion will be much less than 30 years away, and at that point, I guarantee you that lazy people will still be repeating this joke, because it is literaly the only thing they know about the subject.

"Fusion is always 30 years away" is a heuristic that almost always works. https://astralcodexten.substack.com/p/heuristics-that-almost...

We did nuclear fusion in 1952. Controlled nuclear fusion--and producing more power out than goes in--that's another matter.

Re: Major breakthrough on nuclear fusion energy

#817

Post by AtlasBarfed »

baryphonic wrote: post #806
tsimionescu wrote: post #749

Earlier quoted context omitted.

Fusion is still at the phase of fundamental research in some areas, while others are in a sort of "engineering research". Either way, it's actually hard to imagine fusion will ever be a promising power source, at least with any tech resembling what we know today. It is extremely complex technology living in proximity to extreme radiation bombardment and extreme temperature differences. A fusion reactor will need basi…

Not an expert at all in this area, but my understanding was that CFS' design addresses the neutron bombardment problems and the tritium breeding problems by making the reactor smaller and enveloping it in some sort of molten salt. Because the wall is smaller, they plan on being able to replace the inner wall yearly via 3D printing. Wind & solar are fine where they make sense (i.e. windy or particularly sunny places),…

The LCOE of wind/solar is under natural gas, and sodium ion batteries will hit the market this year or next according to CATL press releases (always a grain of salt until you see the product on the market).

They are supposed to be half the cost of LFP.

And let's face it, nat gas / coal are effectively subsidized by ingrained government policy while they SHOULD be subject to a ten year escalating carbon tax.

Nuclear is still ... ok, it's on the high end of solar/wind deployments.

Perovskites may solve even more problems, but that hasn't really panned out like hoped, probably a ten year project.

Wind and solar don't require "huge areas of land". Well, not new land or land we need. There's a LOT of roofs everywhere. Residential power can be almost completely addressed with rooftop solar + storage, I haven't seen single family homes that need "more than the roof", and the excess can go to multifamily buildings.

Windmills can be offshore, or sticking out of farmland or nature preserves.

Utility solar can use deserts, there's plenty of that. I hate the hype about "green hydrogen" since it is a shadow play by oil companies to keep other "color" hydrogen sources which are invariably oil/gas.

Fusion should continue to get research dollars. We should be pursuing LFTR and other new gen fission.

But let's be real, no fission or fusion project initiated now will be ready in ten years, and no one can predict the price of solar/wind/storage in ten years. It won't drop like the previous ten years, but there is enough in the works that it will likely drop ... 50%?

I don't think new fission/fusion can be commercially planned until wind/solar/storage prices stabilize. It doesn't matter how cool a fusion reactor is if the energy it produces is 3x the cost of wind/solar.

I think the hardest thing to say about fusion is that the "it's always 20/30/40 years in the future" was always a technological commentary.

But now the new challenge even if they get a working plant in 20/30/40 years is "is it cheaper?"

Constant 3D printing reactor walls sounds like an expensive proposition. Granted I think the same strategies are in LFTR designs since the materials is hard there too. Liquid metal fusion and molten salts has all the materials engineering and endurance issues LFTR had. I guess fusion fuel is effectively liquid though, so they could just move the liquid to another generator while they "overhaul" the one that has neutron degradation. I figured if LFTR hit mainstream they would do the same: mass produce the reactors and then just move the fuel between them as they wear out, and then recondition the "spent reactor".

Can a LFTR expert comment on whether it can "burn"/breed/transmute/process most nuclear waste as usable fuel, or at least move the isotopes to other better isotope decay paths? LFTR is supposed to be able to use 99% of its thorium fuel without nuclear waste.

Re: Major breakthrough on nuclear fusion energy

#818

Post by immmmmm »

nr2x wrote: post #813
immmmmm wrote: post #607

Earlier quoted context omitted.

To change the game for the survival of our species (if protecting a species that destroyed 75% of ecosystems as of today is really sth wanted anyway) we might want to protect the other species as well since we rely on them almost entirely for anything relevant to survival. Also I am not sure having ten times more energy would do any good. IPBES reports as well as the literature in relevant conservation journals are r…

Yes fully agree but step one on that path is to stop dumping carbon into the air and oceans.

Agreed, but thinking that a new energy source will solve that is completely incorrect. It can help, yes, but it's not a given fact that it will.

Re: Major breakthrough on nuclear fusion energy

#819

Post by rewgs »

ComputerGuru wrote: post #297

> It's not a massive energy output - only enough to boil about 60 kettles' worth of water. This made me laugh. How much more British can you get?

...for five seconds, no less. Just now beating a record set back in 1997.

That sentence really hit me. Is that really only how far we've come? If so, the pace is so glacial that...I don't know, maybe this isn't worth it?

Re: Major breakthrough on nuclear fusion energy

#820

Post by tsimionescu »

baryphonic wrote: post #806
tsimionescu wrote: post #749

Earlier quoted context omitted.

Fusion is still at the phase of fundamental research in some areas, while others are in a sort of "engineering research". Either way, it's actually hard to imagine fusion will ever be a promising power source, at least with any tech resembling what we know today. It is extremely complex technology living in proximity to extreme radiation bombardment and extreme temperature differences. A fusion reactor will need basi…

Not an expert at all in this area, but my understanding was that CFS' design addresses the neutron bombardment problems and the tritium breeding problems by making the reactor smaller and enveloping it in some sort of molten salt. Because the wall is smaller, they plan on being able to replace the inner wall yearly via 3D printing. Wind & solar are fine where they make sense (i.e. windy or particularly sunny places),…

> CFS' design addresses the neutron bombardment problems and the tritium breeding problems by making the reactor smaller and enveloping it in some sort of molten salt. Because the wall is smaller, they plan on being able to replace the inner wall yearly via 3D printing.

My understanding is that even these molten salt or molten lithium blankets can only catch some of the neutrons - so the magnets and other outer structures will still get neutron bombardment, and the tritium you can produce will not fully replace the tritium you put in. The once a decade or two replacement of the entire reactor number I heard was predicated on a shield like this - without a shield IT would probably be once every few years.

Note that I am not claiming wind, solar and fission don't have problems. It's just that they all seem to be much simpler problems than fusion has, fundamentally, even in the long run.

I'm not suggesting we shouldn't keep researching fusion technology, but I also don't think it can or should he treated as a priority, or as if once it's done it will solve all of our energy woes. It will take a huge amount of time even after the first actual plant is operational until fusion becomes in any way economical and widespread, with initial fixed costs that will make fission seem like chump change.

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