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Japan's JT-60 Tokamak Sets New Plasma Record
Posted by
Zonk
on Sat May 13, 2006 03:39 AM
from the road-to-the-fusion-reactor dept.
from the road-to-the-fusion-reactor dept.
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."
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Almost there... still (Score:5, Funny)
Let's see, 400 seconds - 28.6 seconds .... works out to about 50 years. Still.
Re:Almost there... still (Score:3, Funny)
Re:Almost there... still (Score:4, Interesting)
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.)
Parent
Re:Almost there... still (Score:3, Funny)
I was supposed to have a time-traveling DeLorean by now.
Did anybody else read "400 seconds" as "88 MPH?"
Only 10 years till FUSION! (Score:4, Funny)
Look at that, it'll be completed in exactly 10 years. Finally, this time 10 years means 10 years.
Subject? (Score:5, Funny)
WOW! (Score:5, Interesting)
Why so slow? Why no larger investments? (Score:4, Interesting)
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.
Why is Tore Supra ignored here ? (Score:3, Informative)
As far as I can read, it seems rather impressive. Their record for plama duration is... 390s ! More information on the fusion-dedicated French CEA (Commissariat à l'Energie Atomique) site [www-fusion...que.cea.fr] (in English).
But the question is honest: what have achieved the Japanese? Is their plasma self-sustaining? Have they reached break-even point and maintained it during the whole 28.6 seconds?
Anyway, just give a look to the CEA site: from pictures to videos, plenty to discover there.
My prediction (Score:3, Insightful)
For God's sake!! (Score:5, Informative)
K, I am doing a PhD in Fusion in one of the best fusion plasma groups in the world. I would be happy to answer any questions.
Not having a go at any random posts, but just a few mistakes I didn't see get checked. 1. Yes Fusion is safe, very safe, super safe. Safe!! You can ask me why, but no-one ever seems to pay attention, or even understand.
2. Fusion weapons have been around since at least the 1960's! Hydrogen bombs. Kinda like 50 years too late to be scared about that one.
3. Would you like to know why fusion isn't here yet? It's very difficult! It's not an oil conspiracy!! The people in fusion are academics and believe me when I say they don't generally give a crap about money. They are smart people concerned with the environment.
4. Why is it difficult? You can't switch JET or MAST on for too long because of Ohmic heating. It basically implies that super conducting (very $$$!) coils are needed to get around this problem. ITER will be one of the first reactors to have all superconducting coils.
6. Anything else? Yes, actually. We are literally making it up as we go along. How many people know exactly what a plasma is? I mean what defines it? It's Debeye length? Collisionless? Quasi-neutrality? What do any of these terms mean? If you don't know you probably aren't qualified to talk on fusion. Plasma physics is relatively to the rest of science an incredibly new and young field and it is extremely varied.
There's lots and lots going on in fusion. I apologise for the lack of links but i'm typing quickly and don't have time. Suffice to say, everyone in the fusion community is very enthusiastic about it. It is getting more and more (international) money all the time. The Chinese and Japanese are involved, not to mention India and the most of the West.
On an interesting side note. The thing that mainly held fusion back was
can you guess?
AMERICA!! Constantly pulling in and out of the project. However, now that the Indians are involved the funding is about 110% of what is required. So if the yanks pull out again then they will fall behind because no-one else cares anymore and we'll have enough money to, and we will, continue.
Re:How long (Score:3, Funny)
It's about fifteen years away.
Five years ago, it was about ten years away. That's progress for you.
Re:How long (Score:5, Informative)
No meltdown risk...
No long-lived waste products...
No dangerous fuels...
Likely no immediate danger of weapon proliferation...
And you have to ask if it's safer?
Just so we're clear, fission power is reasonably safe already (provided the reactors are well designed and maintained, and provided that the waste is reproccessed). All of the dangers of a fission plant are outlined above, and they're not that bad when compared with the alternatives. Fusion has none of those dangers; the nuclear reaction ceases if the reactor vessel loses confinement, the major waste product is helium-4 (which is commercially useful and chemically inert), reactor irradiation is minimal, and can be limited further by careful choice of building materials, the fuels are safe to handle, and there's no way to make a bomb out of the reactor technology that we know of yet.
That's not to say there are absolutly no problems. Even with careful material selection, the reactor vessel will become slighly radioactive over it's lifetime. But safer and cleaner than fission? Yes, and by an order of magnitude at that.
Parent
Re:How long (Score:5, Informative)
Now I freely admit that things may have changed in the 7 or so years since I quit my Phd in plasma physics, but back then that simply wasn't true. One of the major byrpoducts of a fusion reaction is (was) a pretty steady flux of neutrons. Being neutral, the only way to contain it is to absorb it. This shielding will become radioactive, and will need to be replaced periodically. It is inevitable that eventually, the entire reactor will have been damaged to the point of having to be replaced; it will all also be radioactive.
Now it's true that the half-life of the irradiated components is much, much shorter than that of the waste products of fission, and (imnho) fusion is absolutely the way to go long-term for nuclear power. However, I really don't think it's true to say "reactor irradiation is minimal".
Like I said though, it's been some time since I last really looked at this, so it's possible that progress has been made. It's also not impossible that I'm mis-remembering things (or simply misinterpreting your meaning), of course.
Parent
Re:How long (Score:5, Informative)
Remember that the object of comparison here has the same issue with neutron irradiation (ie, even ignoring waste products, a fission reactor core will become irradiated over time, as will the coolant in the heat exchangers). In addition to the neutron problem, which applies to both fission/fusion, you've also got to consider direct radioactive contamination from the fuel/waste. At least with a fusion reactor we can eliminate (or reduce) the risk of elements like strontium-90, since we get the option of choosing what radioactives we want left over at the end of the plant's life when we build it.
But I cede the point that, objectively, the degree of radioactivity in the core of a decomisioned plant would not be "minimal" by human standards.
Parent
Re:How long (Score:5, Informative)
And I'm not just being flippant, though the answer has been 50 years for the last 30 years or more.
ITER isn't going to be operational until 2016 at the earliest, and it's an experimental reactor not expected to be a net energy producer. Based on operational experience with ITER and IFMIF (for which construction has not even started), another experimental reactor will be designed and constructed with the goal of net energy production. Perhaps that might be operational by 2035. And if it works well enough, it's *remotely* possible that a commercial reactor could be designed and constructed, and be operational by 2055.
When all is said and done, fusion recactors are expected to produce *slightly* less expensive electricity than fission.
The big win with fusion will require a major theoretical breakthrough rather than simply carrying the current plans to their logical conclusion.
In general it's reasonable to expect that they'll be cleaner and safer. There is no possibility of a runaway chain reaction; the reactor only contains enough fuel at any given time to operate for a fraction of a second, vs. months or years for a fission reactor. If the fusion reaction containment fails, the reaction quickly stops, without serious damage to the reactor and without any abnormal leakage of radioactive material. A fusion reactor can't "melt down".A fusion reactor will produce a greater quantity of radioactive waste (crumbling radioactive shielding and structural materials after years of exposure to high neutron flux), but fortunately the waste will have a very short half-life so it won't be dangerous for too many decades, and will thus be easier to store. No need to worry about safety over geological time scales, or about whether our descendents will be able to read warning signs printed in 21st century languages.
Parent
Re:How long (Score:3, Funny)
If the fusion reaction containment fails, the reaction quickly stops, without serious damage to the reactor and without any abnormal leakage of radioactive material. A fusion reactor can't "melt down".
Unfortunately, like most reactors, it will collapse into a pile of rubble after exactly 50 years. Which is why I prefer to use hydroelectric power...
Oh, wait, we were talking about Sim City, right?
-:sigma.SB
Re:How long (Score:5, Informative)
Parent
Re:How long (Score:3, Interesting)
Re:greens (Score:3, Funny)
If you want nuclear to succeed, you need to find a greater evil, for example:
"
Scientists have released details of a discovery last month that when a tiny adorable kitten is poked with something pointy and sharp, an incredible amount of energy is released, many many orders of magnitude more energy than the kitten would consume in food during its entire life.
The
Re:fusion - can you count neutrons? (Score:3, Informative)
The short of it is that fusion is rather dirty - just as bad if not worse than fission and the reason is because of all of those neutrons that are released.
Forget about OIL & GAS dropping in price for any length of time.
Saud
Re:fusion (Score:5, Insightful)
Perhaps, but when your fuel source is the most abundant substance in the universe, there's "close enough for engineering purposes."
"Where is the balancing "bad" for fusion energy?"
You seem to be confusing thermodynamics with kharma.
Parent
Re:Is the almost exclusiv funding of fusion worth (Score:3, Insightful)
Efficient. Reliable. Decentralized. Pick any two.
Re:Competing Technology of Cold Fusion (Score:3, Funny)
Actually... (Score:3, Interesting)
First off, the spherical chamber: Do what Operation Plowshare did, use a nuke to build the chamber by detonating it underground. I bet that if you mined ventilation shafts at the near "edge" of the explosion, you could vent off the overpressure. The heat from the explosion would sinter the rock together. All that would be left would be to send in some remote-controlled mining equipment to "smooth" it out. You aren't t