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Japan's JT-60 Tokamak Sets New Plasma Record
Dipster writes "The Japan Atomic Energy Agency has announced that its JT-60 Tokamak has almost doubled the previous record for sustained plasma production, which is now sits at 28.6 seconds. It is believed that once 400 seconds can be achieved, a sustained nuclear fusion reaction will be possible. While 28.6 seconds is a long way from 400, it raises hopes for what will be possible from the ITER reactor, expected to be finished in 2016."
Let's see, 400 seconds - 28.6 seconds .... works out to about 50 years.
If you assume that they'll only be able to increase the time linearly, then yes, it's about fifty years.
If you assume that they'll be able to keep refining the technology and keep doubling the time every two years, then we're only looking at 7.6118259 [2*log(400/28.6)/log(2)] years.
It's probably somewhere in between that, though I'd guess toward the lower end. (As they keep getting closer, more attention will be given to the problem, etc.)
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As a bachelor degree student in physics in the 70's and early 80's, fusion research was on of the 'hot' topics. The tokamak was the predominant fusion plant, but other fusion reactors were being investigated. In those days we measured sustained reaction times in milliseconds. Obviously I haven't been keeping up, 'cuz 28 seconds sounds like a lifetime to me now.
-- There are 10 kinds of people in the world, those who understand binary and those who don't.
The actual research itself is relatively unpredictable, I understand that. But when I read that completion of the ITER (the way I see it a relatively straightforward job, I assume the blueprints are already completed) is still 10 years away, I wonder how much time could be shaved off that estimate, as well as the ~2050 estimate, if (a lot) more money were put into fusion research.
If nuclear fusion has the potential to provide a clean, efficient, lasting energy source, and thereby eventually solve the energy crises, it would seem to me that investing a far larger amount of money than is being put into it today would be a very good investment if that could mean nuclear fusion can be used a few years earlier. I think ITER's cost is estimated at about EUR 10 billion, which is a lot of money, but in the grand scheme of things (I think the world GDP is somewhere around 50 trillion) it's tiny. And seeing the large potential for creating armed conflict there is in energy shortages even these days, I'd say getting fusion sooner rather than later may very well be a real matter of life and death.
However, when I hear discussions on the energy crises, the efficiency of solar/wind/water power, whether more nuclear fission reactors should be built, fusion isn't even mentioned, let alone considered by politicians for larger investments. Is it simply because it's so far away, and that for the most of us, only our descendants would benefit from those investments?
Once again this is a serious question, I'm no expert in any of this so I honestly don't know.
Also, Tore Supra has achieved discharge durations in excess of 200 seconds since 2002 and has more recently had shots in excess of 360 seconds (6 minutes). Of course Tore Supra has a significant advantage over most other tokamaks in that it has superconducting toroidal field coils, giving it a steady state toroidal magnetic field. My experience in working with these machines is that on most of them the toroidal magnetic fields seriously handicap their performance due to the massive power requirements of generating a typically > 1 T magnetic field. This brings in the requirement for expensive and bulky power supplies and energy storage devices such as large capacitor banks and flywheel generators. The Joint European Torus has two 3750 MJ flywheel generators that can supply as much as 800 MW (400 MW each) of peak power which are used for the toroidal and poloidal magnetic field coils. The magnetic field coils on JET consume more than half of the power required to run the machine. The remaining power is drawn directly from the grid. Using superconducting magnetic coils greatly reduces the power required to run a tokamak and extends the time over which the discharge can last. Tore Supra has a goal of, I believe 1000 second discharges, which is similar to what ITER will be aiming for.