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Construction of French Fusion Reactor Underway
GarryFre writes "It has been said that fusion is 50 years away for quite a few decades, but now work has actually been started. Digging has begun in the south of France on the planned site for France's first fusion reactor. A tokomak is a torus shaped magnetic confinement device which is necessary to withstand the temperatures associated with fusion that are so high, solid materials can't hold them. As such, the building represents the future core of ITER (International Thermonuclear Experimental Reactor.) It will be interesting to see if it takes 50 years to build it."
LE DAILY NEWS
Wednesday, September 15, 2060
The country formerly known as France has successfully performed its first and last Fusion reaction.
It may well be physically in France, I wouldn't call it French per se. The I in the name most assuredly stands for International, with technical and financial input from around the world (China, the EU, India, Japan, Korea, Russia, and the USA, in alphabetical order).
It's a project we all may ultimately depend on as a civilisation, so the International part is important.
We'll do but we'll call it "Freedom Fusion".
"There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed H
That eternal "Fusion is 50 years away" saying stopped being due to physics and started being due to squabbling countries and their bureaucracies many years ago. ITER could have been started over a decade ago.
Free the Quark 3 from asymptotic confinement! Bring your charm! Don't get down! All colours and flavours welcome!
I guess your Free World doesn't have any gypsies in it.
Actually, ITER is intended to demonstrate a useful amount of energy production from fusion. It's baseline design is for Q=10, i.e. 10 times more power out from fusion than put in. This is essentially a feasibility demonstration, and experimental test bed for things like wall modules and blankets. The follow-on (DEMO) will then be a prototype power plant, and actually be connected up to generators etc.
ps. though AC, also a plasma physicist working on tokamaks
There are two main reasons why it is thought that ITER can achieve more power out than in (10 times more in fact)
1. It is about 8 times the plasma volume of JET (about 2x in each direction). The temperature gradients in tokamaks have limits (things like Ion Temperature Gradient mode-driven turbulence) so the bigger you make the machine the hotter you can make the middle of the plasma and the better your performance. The problem with this is that the power output goes like the volume, but the area this power is deposited on goes like the area. Hence why small fusion plants would be nice, and materials are the biggest issue for ITER and DEMO
2. They will be using Tritium in ITER. Tokamaks today have only very rarely used tritium (e.g. JET, JT60-U) to produce more power out than in (very briefly 1s). This is because the plasma physics doesn't really change when you add Tritium, so experiments use Deuterium which is much cheaper and less dangerous (e.g. radioactive). At 100 million degrees, the D-D fusion rate is still pretty small and so the amount of fusion energy produced is tiny. The D-T rate is orders of magnitude higher and so significant power can be produced
p.s. Yes, AC plasma physicist
The whole point of ITER was to "demonstrate" that the science is settled. Apparently "the science" is fully settled. Nevertheless they've made several serious design flaws, and are seriously behind schedule (and below expected results for what they've done too). Nevertheless, they're charging ahead, and all smart people hope they succeed.
Btw, there are fusion reactors in most large hospitals, for neutron production. They're called "fusors" and they're basically a rolled up television display. Additionally these (very simple) devices are used for scientific research in most universities. They're very reliable, but have Q levels around 0.1 up to 0.3 for professionally constructed ones.
Imho, I think the American research plan is smarter than the European one. At the very least for the simple fact that Europe is throwing all their eggs in the same (proven to be somewhat unreliable) basket. America may be underfunding fusion research, absolutely, but at least America's underfunding 5 different attempts (including steam-based fusion, my favorite). But there are others, and there are even hybrid machines (meant to do research and to produce fusion, e.g. Z-pinch, or the Z-machine). Also there are several American tokamaks, just in case that's the solution after all.
The tokamak approach banks on pushing back to all forces that act on a fusing plasma, and it's like placing 2000000 small propellors on the ground to control a raging thunderstorm. I'm not saying it will never work, but I'll be utterly amazed. There are other approaches. Hydrogen bombs, on the plus side, they're proven to be effective. On the downside ... well ask some pacific ex-islands ... they know. Then there's inertial confinement fusion, where you generate a number of (relatively) small forces that converge on the same point. For a short time, huge forces will act on this small point, generating fusion. Steam-based fusion is an example, but so is laser fusion, and essentially Z-pinch too. There's also the polywell, an evolution of the only type of fusion rector in commercial use, the fusor, which is a fusor with a magnetic field to replace the fusor grids (google "should google go nuclear ?"). There's even a few attempts that involve principles that boil down to shooting high pressure gas in what's essentially a funnel, resulting in huge pressures just behind the end of the funnel. And I don't really understand how the Z-pinch is supposed to work.
Actually, it's not hyphenated.
Which is still a tiny bit short of the 100,000,000K that they're looking at. http://en.wikipedia.org/wiki/Iter#Reactor_overview.