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Scientists say they have cleared technical hurdle in fusion research
Posted on Monday, May 22, 2006 @ 18:04:02 GMT by vlad
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Physicists working in the United States believe they have cracked an important problem facing man-made nuclear fusion, touted as the cheap, safe, clean and almost limitless energy source of the future.
In fusion, atomic nuclei are fused together to release energy, as opposed to fission -- the technique used for nuclear power and atomic bombs -- where nuclei are split.
In a fusion reactor, particles are rammed together to form a charged gas called a plasma, contained inside a doughnut-shaped chamber called a tokamak by powerful magnetic coils
A consortium of countries signed a deal last year to build the International Thermonuclear Experimental Reactor (ITER) in southern France as a testbed for an eventual commercial design.
But many experts have been shaking their heads at the many challenges facing the ITER designers.
One of them is a phenomenon called edge localised modes, or ELMs.
These are sudden fluxes or eddies in the outer edge of the plasma that erode the tokamak's inner wall -- a highly expensive metal skin that absorbs neutrons emitted from the plasma.
Erosion means that the wall has to be replaced more often, which thus adds hugely to costs. Eroded particles also have a big impact on the plasma performance, diminishing the amount of energy it can deliver.
Writing on Sunday in the British journal Nature Physics, a team led by Todd Evans of General Atomics, California, believes that the problematic ELMs can be cleverly controlled.
They found that a small resonant magnetic field, derived from special coils located inside a reactor vessel, creates "chaotic" magnetic interference on the plasma edge, which stops the fluxes from forming.
The experiments were conducted at the General Atomics' DIII-D National Fusion Facility, a tokamak in San Diego.
Nuclear fusion is the same process used by the Sun to radiate energy. In the case of our star, hydrogen atoms are forced together to produce helium. On Earth, the fusion would take place in a reactor fuelled by two istopes of hydrogen -- deuterium and tritium -- with helium the waste product.
Deuterium is present in seawater, which makes it a virtually limitless resource. Tritium would be derived from irradiating the plentiful element lithium in the fusion vessel.
The 10-billion-euro (12.8-billion-dollar) ITER scheme entails building the largest tokamak in the world at Cadarache, near the southern French city of Marseille.
The partners are the European Union, the United States, Japan, Russia, China, India and South Korea.
It is designed to be a test bed of fusion technologies, with a construction period of about 10 years and an operational lifespan of 20 years.
If ITER works, a prototype commercial reactor will be built, and if that works, fusion technology will be rolled out across the world.
Other problems facing fusion technology include the challenge of creating a self-sustaining plasma and efficiently containing the plasma so that charged particles do not leak out.
In the various tokamaks, no one has achieved a self-sustaining fusion event for longer than about five seconds, and at the cost of using up far more energy than was yielded.
A huge jolt of heat, of nearly 100 million C (180 million F), is needed to kickstart the process, which then has to be sustained by tiny amounts of fuel pellets.
© 2006 AFP
Source: http://www.physorg.com/news67442282.html
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"Scientists say they have cleared technical hurdle in fusion research" | Login/Create an Account | 9 comments | Search Discussion |
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Re: Scientists say they have cleared technical hurdle in fusion research (Score: 1) by malc on Tuesday, May 23, 2006 @ 00:15:30 GMT (User Info | Send a Message) http://web.ukonline.co.uk/mripley | What an utter waste of money and resources. Still the scientists working on fusion will be happy that the career they chose decades ago is still being funded!
A quick reminder that's 5 seconds sustained in over 50 years of research and we are expected to believe they will crack the problem in the next 10. If that was a claim made by Mr. Tilley we would be laughing hysterically wouldn't we ?
Is it just me but don't you think that a fusion (or fission) reactor is an incredibly over engineered and dangerous method of boiling water ? At the end of the day that's all the heat is used for, boiling water to turn a steam turbine to generate electricity.
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Re: Scientists say they have cleared technical hurdle in fusion research (Score: 1) by ElectroDynaCat on Tuesday, May 23, 2006 @ 06:45:43 GMT (User Info | Send a Message) | One hundred years from now, the future generations, if there are any left, will be seeing the same headlines.
Along with: we're just 20 years away from getting this fusion thing to work.
Fusion power is neither safe, clean, cheap or practical, If it ever does break even, the capital investment to build a fusion plant will be staggering, and the apparatus will very soon become lethally radioactive from the neutrons that spit out from the plasma.
Fusion research is only driven by politics, not common sense. With the money that has been squandered on fusion , the U.S. could have fully utilized renewable wind power within our boundaries and we would be burning 30% less coal than we do now. |
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Re: Big science would be better on a small scale. (Score: 1) by Randy on Tuesday, May 23, 2006 @ 09:01:18 GMT (User Info | Send a Message) | Fusion research is an attempt to fool the public into beleiving there does not now exist an answer to the energy crisis. There are several existing technologies available to us now that could dramatically reduce our dependence on fossil fuels with little danger to us. Solar photovoltaics promises us inexpensive and decentralized power, but the governments still favor centralized power and huge investments.
The recent breakthrough technology in South Africa (solar cells 5x more efficient and cheaper than any other now existing in the US) may eventually come here. Since the US did not develop this technology, we will have to pay royalties to South Africa. We are falling behind in science.
Our best bet is to invest in nanotechnology. This new technology will make possible methods of extracting useful energy that classical physics says is impossible. One example is the utilization of the Barkhausen effect in ferromagnetic quantum dots. Electronic cooling of ferromagnetic quantum dots leads to the growth of domains in the material and consequently, an increase in magnetic strength. This increase and decrease through the application of an applied magnetic field can induce current in a circuit or self inductance in that circuit.
I would favor our government trying Barkhausen induction before spending billions of dollars on a fusion process that may never happen.
Randy Sawyer |
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Hot Fusion Program Recovers From Four-Year Delay (Score: 1) by vlad on Thursday, May 25, 2006 @ 22:23:40 GMT (User Info | Send a Message) http://www.zpenergy.com | Steve Krivit writes: NEW ENERGY TIMES Your best source for cold fusion news and
information. July 10, 2005 -- Issue #11
Hot
Fusion Program Recovers From Four-Year Delay By Steven
Krivit Controlled thermonuclear (hot) fusion research started 54 years
ago, with the hope of providing clean, abundant energy. Many good scientists
have spent a large part of their career searching for the Holy Grail of nuclear
fusion by bringing the energy that powers the sun down to earth...
Read story here: http://www.newenergytimes.com/news/2005/NET11.htm |
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