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Major breakthrough on nuclear fusion energy

bbc.co.uk

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Re: Major breakthrough on nuclear fusion energy

#231

Post by epistasis »

andruby wrote: post #158
epistasis wrote: post #143

Earlier quoted context omitted.

I guess, why is it thought that it could be cheaper than geothermal, for example? Geothermal doesn't have fuel at all. I don't see how fusion produces energy cheap enough for it to be super abundant. And maybe that's just a failure of my imagination, but there seem to be massive gaps in others' reasoning that nobody has been able to fill me in on. Space travel is an entirely separate type of energy use, and I could s…

Even without fuel, geothermal still has constraints. Where can we build it? What are the build costs and costs to run (maintenance, staffing, etc)? I doubt we can scale geothermal indefinitely. Fusion might suffer from similar constraints, but afaik, doesn't need "much" space or specific geographic structures.

FWIW, drilling tech is advancing at an incredible rate, making geothermal possible in all sorts of new places all the time.

But my primary concern with fusion is cost. I don't see the path to being cheaper than geothermal, nor fission, and new fission is already some of our most expensive energy. The goal may be eventual space travel, which seems like a more plausible goal to talk about than sustainable energy.

Re: Major breakthrough on nuclear fusion energy

#232

Post by willis936 »

dfdz wrote: post #80

> This is more than double what was achieved in similar tests back in 1997. The experiment produced > 11 megawatts of power and at Jet > two 500 megawatt flywheels are used to run the experiments log_2(2*500/11)*(2022-1997) + 2022 = 2185 At this rate we will have fusion by 2185 I guess?

This is a disingenuous argument. JET was not designed as a power plant. Those flywheels are used exclusively to transiently power the copper confinement coils. Since superconduction was discovered, no reactor study has had non-superconducting confinement coils because they are (very obviously) impractical.

Re: Major breakthrough on nuclear fusion energy

#233

Post by ggrrhh_ta »

Retric wrote: post #134
limaoscarjuliet wrote: post #109

According to Sabine Hossenfelder, published numbers are frequently mis-stated on purpose. When you look at frequently reported Q Plasma (or plasma efficiency) we are not that far from it being > 1. However, we should look at Q Total (total efficiency), which is still way below https://www.youtube.com/watch?v=LJ4W1g-6JiY For years, I was hoping fusion is close. After watching Sabine's video, I'm not so optimistic anym…

She makes several significant mistakes in that video. One example is the energy used to heat the plasma is now heat in the plasma identical to the heat generated by fusion. This means you can recover a percentage of that with a steam turbine. Second a great deal of ITER’s energy usage is as a science experiment not a fusion reactor. Most of their monitoring equipment for example is irrelevant to an operating power pl…

But her point stands even if there were mistakes: the press and many scientists, even if unwillingly, have failed to communicate the real state of fusion as an energy source. And I can believe that maybe some representatives did not fully understand the difference between Qtotal and Qplasma and the amount of time a reaction can be sustained (all three things that they would understand if they were explained clearly).

Re: Major breakthrough on nuclear fusion energy

#234

Post by fragmede »

kimbernator wrote: post #119
formvoltron wrote: post #105

OK so with fusion everybody loves it because the fuel would be clean and nearly endless. Isn't that what solar power offers? Nobody wants to deploy solar due to high upfront cost. However, wouldn't the startup on a fusion reactor be much greater?

Solar comes with a lot of challenges for large-scale usage as a replacement for coal, nuclear, etc. Really, the only thing better about solar at the moment is that it is available. First off, the daylight cycle is an obvious concern and there still isn't a great way to store solar energy during the day for use by cities (or generally large consumers) at night. Not to say it's not possible, but people are largely stil…

Pedantically, both are fusion, one's just 1 AU away.

Re: Major breakthrough on nuclear fusion energy

#235

Post by can16358p »

amelius wrote: post #152
twobitshifter wrote: post #91

Earlier quoted context omitted.

Even if it takes 200 years it is likely still worthwhile. Unfortunately we, as a culture, have a problem seeing and planning across generations. https://longnow.org/

> we, as a culture, have a problem seeing and planning across generations From a political perspective, there is little incentive to plan further ahead than the current administration.

Yup, that's exactly the problem. We need to find an incentive for the ones in power to invest in things that would be good for the future.

Maybe I'm going too far but in the future cryonics and being frozen and be brought back when the promise of these investments be resolved in the future might create some incentives.

Even though this seems super-scifi for now, it probably won't be in about 100 years.

Re: Major breakthrough on nuclear fusion energy

#236

Post by grogenaut »

lisper wrote: post #188
SamBam wrote: post #176

Earlier quoted context omitted.

I don't believe that this is entirely mis-stated. We already know that fusion power plants are going to operate by igniting plasma in short bursts -- a few seconds, maybe 10s at most -- and generating a huge amount of power during that single burst. You then ignite it again and again. The question is how much total energy you can extract from each of those bursts. By that metric, the total energy is what's important,…

> "59 megajoules of sustained fusion energy" means a single burst produced that much. In what sense is that "sustained"? A typical power plant produces that much energy in less than a second on a continuous (i.e. sustained) basis. Producing 59 megajoules once is basically a joke. It is analogous to detonating a pipe bomb (at a cost of several billion dollars) and claiming that as significant progress towards an inter…

internal combustion engines do this and are basically sustained. integrate over cylinders and time. Aka diesel or gas generators.

Re: Major breakthrough on nuclear fusion energy

#238

Post by ppaattrriicckk »

moogly wrote: post #175
ppaattrriicckk wrote: post #59

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…

> 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.

I 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.)

Re: Major breakthrough on nuclear fusion energy

#240

Post by dang »

CodeGlitch wrote: post #21
unfocussed_mike wrote: post #13

Earlier quoted context omitted.

If you can read that as a pro-Brexit comment, then the Brexit project succeeded beyond its instigators' wildest dreams. It's not ambiguous at all. Everything in the UK going on right now -- everything -- has a "some of this is unclear or worse because Brexit has destroyed agreements or because proposed, nearly impossible agreements have not been struck" subplot. Brexit has set fire to every kind of international comp…

You do realise that countries can work together without being part of the same trading block? ... If I understand your nonsensical ramblings correctly.

Personal attacks will get you banned here. Please make your substantive points without swipes and name-calling.

https://news.ycombinator.com/newsguidelines.html

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