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U.S. and China Join Fusion Project
Garp writes "According to the BBC News website, the U.S. has finally decided to join the international Fusion project, Iter, along with China, with the aim of building the worlds first commercially viable Fusion reactor. Fusion is one of the cleanest forms of energy conversion, excluding renewable natural sources, like wind farms, tidal generators, and solar cells."
Less than that. I can't give you any numbers, but /.'s history has stories on fusion. Basically, we've long since gotten past the point of getting more energy out than we put in. We just can't sustain it for more than about 2 minutes, yet.
ICF was never principally for power generation; it was a weapons-lab project with energy thrown in as an afterthought to make it look like it had peaceful purposes. The big ICF facility in the states, NIF, is just coming online now... and the future of ICF will have nothing to do with what happens with ITER.
One scheme was to clad the inside of the reactor with lithium, transmute that with the neutrons and then take the resultant material and put that in a fission reactor and then boil steam.
All this mucking about of course makes for a lot of pretty hot nuclear waste and it would never be environmentally friendly.
This is the Deuterium-Tritium, but the tritium-tritium reaction is essential clean; no fast neatrons; however the temperature and pressure is so much higher, that the problems to achieve break-even are greater.
-WolfWithoutAClause
"Gravity is only a theory, not a fact!"Not really. The hazards are about identical- the lithium reactor can still melt down, the fusion reactors certainly become radioactive in and of themselves, and have a finite life due to radiation damage. It's not clean, it may very well not be cheap either.
The tritium-tritium reaction is a different beast though; that's potentially pretty clean, and pretty safe- no fission reactors need be involved. But very much more difficult to ignite.
-WolfWithoutAClause
"Gravity is only a theory, not a fact!"So we'd have fusion technology today if Joe Scmuchatelli had a weak inkling of what happens in a nuclear reactor? I'm afraid you're vastly uninformed about fusion. The problem isn't that Joe Sixpack doesn't know a little, the problem is that Joe Scientist doesn't know the intricacies of how to maintain a fusion reaction. That's why this facility is being built.
Fusion research has reached a stage where the only way to get closer to commercial production is to scale the whole experiment up. You state that there haven't been any experiments to show fusion can be used commercially... Well Duh! Researchers have only recently gotten past the break even point. That's why we call it "experiment", and not "commercial implementation". The problem is not one of not enough qualified workers and thus it's too expensive, the problem is we just don't know how to make a sustainable fusion reactor yet.
AccountKiller
As of the late 80's (last time I was at the Princeton Plasma Physics Lab) the strategy was to clad the reactor in a copper shield. This would create a radioactive copper shield over time, which would need to be stored as radioactive waste. The half-life is only 37 years though.
disclaimer: data from my non-ECC memory
My God, it's Full of Source!
OUTSIDE_IP=$(dig +short my.ip @outsideip.net)
They don't like to mention how many hundreds of tons of material would be made radioactive by the heavy neutron bombardment from hydrogen reactors.
Fusion reactors do not generate high level radioactive waste that must be isolated for geological lengths of time in the way fission reactors do. The radioactive by products from a fusion reactor are low level and with short half-lives (less than 100 years). The short half-life makes in place storage of the irradiated structural components quite feasible - they don't need to be transported etc.
In addition a fusion reactor is fail safe - there is no danger of a meltdown or similar event.
The real attraction of fusion is that it is potentially extremely scalable. Alternative energy sources like solar, wind, etc. are attractive within the near term framework of reducing greenhouse gases over the next decade or two. Ultimately however it is hard to imagine how these dilute, funtamentally limited sources of energy will supply what is needed for strong economic growth into the next century, or a world population that exceeds 10 billions.
The problem with nuclear fusion is that it has been the classic example of a tech that's 50 years away- and it's been that way for the last 50 years. It's turned out to be a much more thorny problem than people anticipated- uncontrolled fusion reactions are fairly easy to produce after all- just direct the energy from a fission primary at an appropriate quantity of tritium. Unfortunately, this is a hydrogen bomb, and makes for a rather inefficient power source.
However, controlled confinement of plasma has proven to be much harder. ITER will use the most popular confinement method, a tokamak, which is a design devised by the Soviets (Tamm and Sakharov) back in the 1960s. So essentially, the basic plan is 40 years old, but there have been a number of obstacles- political and economic as well as technical to making this work. It will be interesting to see if their tokamak avoids the key problem of the design; in a tokamak, the plasma itself has an internal current running through it (as opposed to other designs like stellarators) and has proved rather deifficult to contain in the torus. I believe the Joint European Torus has had several "disruptions" of this sort that have lifted the several hundred ton vessel off its bolts. The good news, of course, is that such events (which are rare, and should be much more rare in a non-experimental reactor) are really the worst things that can happen to a fusion reactor. Although the plasma is extremely hot, it is not very dense at all (obtaining a critical density is really the greatest challenge) and thus there exists no possibility of 300 million Kelvin plasma vaporizing the container walls in some sort of runaway accident. Also, while they are not completely clean (no power generation method is) the radioactivity produced is low level, especially in comparision with fission reactor spent fuel rods.
"FDA staff reviewers expressed concern about the number of patients who were left out of the study because they died."