Tokamak fusion

[Relick]

Sorry that I'm not very informed on this, but then why do people say there isn't enough helium for dirigibles to be viable?

Edit: I'm talking about how you said we have millions of years worth of helium-3.

That's not what he meant. He said that it will be millions of years before we run out of power in order to start using He3. There is a lot of He3 outside of the Earth, just getting to it and mining it is so expensive the potential energy return may not be worth it.

[Scotius]

There is some helium-3 in Moon's soil we could use after setting up large scale mining and refining operations. More is present in the atmospheres of gas giants - but mining (or scooping?) it would be more difficult i guess. We are not going to probe Uranus for helium-3 anytime soon. Nonetheless it is there, and second generation of fusion reactors burning He-3 would be much more effective than first generation.

[magnemoe]

That was all very interesting, but predictions and opinions of broad socio-economic and political trends are essentially a moot point to what the thread is about - fusion, specifically through the use of tokamak type devices.

Based on the lessons that have been learned about how plasma physics and controlled fusion seem to work (a process that was far harder than initially thought - hence the parroted "perpetually 20 years away" line), in conjunction with the ability to model this physics, ITER was designed as a final test. As with every model, our understanding of what's going on with fusion needs validating conclusively, current experiments such as JET show that the fundamentals are strong, which is why the money was released to be spent on building ITER. Once it's finished in around a decade, the question is almost certainly going to change from "is it possible" to "is it economically viable" to use tokamak based fusion for large scale power generation.

Yes, on the other hand I have no more faith in getting Tokamak fusion to work than polywell or focus fusion. Note that both of this would be an far simpler and cheaper reactor design. So many fusion projects going on that some of them will work. And fusion works problem is to getting more useful energy out of it than you put in. You could make an fusion rocket engine with very high isp today, downside is that you would have to feed it energy so it would work like an heavy ion engine with better isp.

The demographic challenge is indeed unique, dropping birth rates and aging population worldwide is unique. The effect will hit china far harder than the west.

Most of the arab world and south america is also below replacement birth rates.

[Britpoint]

Yay. Always like to hear about fusion news. It's funny, I remember a couple of years ago people saying to me "If it ever happens it won't be in our lifetime". Then last year it was fifty to seventy years. Now it's twenty. I'm half-suspecting a commercial reactor to be unveiled Mid-August.

It took us 66 years to go from powered flight to a moon landing. Now a far more advanced scientific civilization needs to make the leap from "Being able to produce Fusion power" to "being able to produce sustainable fusion power". I think we'll manage it. Frankly from a progression of knowledge standpoint I reckon we could have it done in a year - the remaining decades are taken up by construction workers putting all the metal in place.

[czokletmuss]

There is a race going on between technology opening up new horizons and our demand for growth. In a world of finite resources, it is going to take a lot of sustained effort for our productivity curves to keep up with the exponential demand curves. At some point in the future, those curves are going to intersect (if they haven't already), at which point we start losing the race. At some point, growth is going to have to slow down (it already is in the more developed countries), but our entire civilization is based on infinite growth, which is simply not possible.

If we want to survive, we are going to have to go through a serious rethinking of how the economy works, how we share wealth, and how we maintain a decent quality of life. I don't see how that sort of revolution can happen without a major conflict between those that want a better share of the wealth and resources and those that don't want to give up their share.

I agree completely. A good example of completely uneconomic way to use precious resources is our transportation system. We pump oil from beneath the sea to burn it in a 20-30% efficient engine so it can move 1,5-2t of a car and 60-90kg of a person for most of the time. Isn't this just amazingly stupid and wasteful?

[Rune]

Yay. Always like to hear about fusion news. It's funny, I remember a couple of years ago people saying to me "If it ever happens it won't be in our lifetime". Then last year it was fifty to seventy years. Now it's twenty. I'm half-suspecting a commercial reactor to be unveiled Mid-August.

It took us 66 years to go from powered flight to a moon landing. Now a far more advanced scientific civilization needs to make the leap from "Being able to produce Fusion power" to "being able to produce sustainable fusion power". I think we'll manage it. Frankly from a progression of knowledge standpoint I reckon we could have it done in a year - the remaining decades are taken up by construction workers putting all the metal in place.

Don't be so quick. ITER is unlikely to produce much of value towards a commercial reactor, and it will take years at doing that. Of course, some other group (my personal hope is the guys behind Polywell) could give us the good news much sooner, but it won't happen tomorrow. I fully expect to see an artificial sun before I die, though.

Rune. If it can be imagined, it's only a matter of time before it's done.

[drakesdoom]

Rune. If it can be imagined, it's only a matter of time before it's done.

Or a really big explosion, one of the two.