• Security incident: ISF was recently accessed by intruders. Please change your password, and change it anywhere else you used it. Read more

Merged How Close is power from Nuclear Fusion

Puppycow said:
This is the ultimate problem. Even if we assume that they finally figure this out and are able to make a piece of equipment that can stably sustain a fusion reaction and figure out a mechanism that can turn the surplus energy produced by the reaction into electricity, what if it's just plain too expensive in the end?
Click to expand...
Then we should still do it, just on a much more limited scale, and probably just for research purposes.
 
If it's sustainable, it's not explosive. At least not in the sense that I normally understand "explosive". Are you thinking, what if the reaction releases more energy than can be contained by the reaction vessel? Because that seems like a relatively minor engineering problem, if you're able to run a sustained fusion reaction that is (a) net surplus and (b) produces a harnessable surplus.

We've run into this problem before, with internal combustion engines (which really are explosive). A major obstacle to heavier-than-air flight was coming up with materials that were strong enough to contain the explosions of the ICE, but light enough to be carried into the air by the power they were producing. And we've run into this problem, too with fission reactors. It's just a matter of building a heavier, stronger containment vessel.

My expectation is that if we do ever figure out sustainable, harnessable fusion power, we will inevitably figure out a suitable containment vessel.
 
Roboramma said:
Am I missing something? I don't think anyone said anything about fusion reactors being explosive.
Click to expand...

Ah. Yeah, my bad. Puppycow wrote too expensive, I read too explosive.

Anyway, I'm not sure "too expensive" is a real problem. If it's sustainable and produces a net surplus of energy, it's a practically unlimited source of power. The fuel for it is water - abundant and cheap. How could that be "too expensive".
 
Setup costs. The fact that it will pay for itself over time doesn't mean that you don't have to find the setup funding now.
 
theprestige said:
Ah. Yeah, my bad. Puppycow wrote too expensive, I read too explosive.
Click to expand...
, Ah, thanks, that makes sense.

Anyway, I'm not sure "too expensive" is a real problem. If it's sustainable and produces a net surplus of energy, it's a practically unlimited source of power. The fuel for it is water - abundant and cheap. How could that be "too expensive".
Click to expand...

arthwollipot said:
Setup costs. The fact that it will pay for itself over time doesn't mean that you don't have to find the setup funding now.
Click to expand...

This, but also the fact that it produces net power, even with near zero fuel costs, doesn't mean it will pay for itself over time. Even ignoring maintenance costs, which could be very large, and other running costs (even if fuel is cheap you may need many highly skilled workers), the cost of capital isn't zero. If it costs a billion dollars to build, you either need to get a billion dollar loan, and thus have interest payments, or you've got a billion dollars and you put that into building your fission plant instead of investing it in something else. The opportunity cost is basically the same as the interest on a loan. To be profitable, to "pay for itself over time", that plant needs to produce an income greater than those interest payments. Depending on the upfront cost of building the plant, and the amount of net power it produces, that may or may not be possible.

Ie. If you borrow a billion dollars to produce a fission plant that completely runs itself and has not operating costs, but produces only 1 kilowatt of net power, you'll end up going deeper and deeper into debt. And if you financed it yourself you'll end up with less income than you could have had by investing that money elsewhere.
 
theprestige said:
Ah. Yeah, my bad. Puppycow wrote too expensive, I read too explosive.

Anyway, I'm not sure "too expensive" is a real problem. If it's sustainable and produces a net surplus of energy, it's a practically unlimited source of power. The fuel for it is water - abundant and cheap. How could that be "too expensive".
Click to expand...

We would also need supply of material from CANDU reactors (tritium), or go to the far side of the moon for it, or find a way to run all future fusion reactors perfectly, which I highly doubt will happen.
 
There have been so many false alarms about a breakthru in Fusion that will beiieve it whent he first fusion power plant starts operating.
 
dudalb said:
There have been so many false alarms about a breakthru in Fusion that will beiieve it whent he first fusion power plant starts operating.
Click to expand...
Those haven't been false alarms. They have been genuine breakthroughs and extremely necessary if we're going to crack this nut.

We just need about ten thousand more of them. Turns out it's complicated and hard.
 
theprestige said:
Ah. Yeah, my bad. Puppycow wrote too expensive, I read too explosive.

Anyway, I'm not sure "too expensive" is a real problem. If it's sustainable and produces a net surplus of energy, it's a practically unlimited source of power. The fuel for it is water - abundant and cheap. How could that be "too expensive".
Click to expand...

Others have chimed in already with most of the points I would have made. I do wonder though if plain old water is actually sufficient as a fuel or if you need special isotopes of hydrogen such as deuterium and tritium. Those are far less common, and the process to sort them from the most common isotope, which accounts for 99.9855% of naturally occurring hydrogen, could be expensive in itself. If deuterium is sufficient, that seems to cost about $2,500 per kilogram (for heavy water). Tritium is even pricier, at about $30,000 per gram ($30 million per kilogram).

The ITER experimental reactor is set to cost about 20 billion euros and won't even produce electricity.

https://en.wikipedia.org/wiki/ITER

So yes, I think it's quite plausible that even if we figure out how to do it, it will still be much more expensive than other ways of generating commercial electricity. Regular water may not be all that is needed as fuel.
 
Inching closer?

Korea’s ‘artificial sun’ achieves a record 48 seconds at 100 million degrees. Why does it matter?

KSTAR serves as a pilot for the France-based International Thermonuclear Experimental Reactor (ITER) which Euronews Next visited last year. The “artificial sun” provides information that will help better understand fusion.
Click to expand...

and
“To achieve the ultimate goal of KSTAR operation, we plan to sequentially enhance the performance of heating and current drive devices and also secure the core technologies required for long-pulse high-performance plasma operations,” he added.
Click to expand...
 
Roger Ramjets said:
30 seconds in 2021, 48 seconds in 2024. 'Inching' is right. At this rate they'll have reached 2 minutes by 2032. Woohoo!
Click to expand...

I'd be happy with that, but they're actually shooting for 5 minutes by 2026. It seems reasonable to surmise that once they get the hang of sustaining the reaction, new records will start coming quicker and quicker.
 
If I understand these tokamak experiments correctly, they're about using brute magnetic force and computing power to control a chaotic mass of plasma. That is to say, less like the oft-invoked "magnetic bottle" metaphor of a magnetic field just quietly containing all the plasma, and more like a bunch of magnetic Pong paddles frantically maneuvering to shove wayward streams of plasma back into place.

If that's so, then once the design and coding of the system reaches a certain threshold of adequacy for that task, we might very well be seeing rapidly increasing containment times.

What comes after that? Do they need to further pinch (compress) bits of the plasma to make enough fusion happen? Or step up to even higher temperatures? Or use different H isotopes? Or is there enough fusion happening already, and the additional heating from that is one of the limits on containment time? (In which case, it appears there's no way yet to remove the generated heat from the chamber or make use of it.)
 
You must log in or register to reply here.

Share this page

ISF - Join now!

Every member here is approved by hand. No bots, no spam, just people who care about evidence and honest debate.

Membership is free!

Create your free account

Back
Top Bottom