Posted on 01/15/2005 9:23:09 AM PST by ckilmer
Fusion Redux
BY JIM WILSON Photo by Donna Coveney/MIT
After being virtually abandoned, fusion power is poised for a comeback. Nuclear fusion is the process that powers the stars. For more than 50 years, scientists have been trying to bring that power down to Earth. Fusion generators are appealing because they produce none of the pollutants associated with fossil- and nuclear-fuel power plants. Researchers at the Princeton Plasma Physics Laboratory in Plainsboro, N.J., estimate that a 1000-megawatt nuclear fusion plant would produce about 4 pounds of waste a day, compared to 31,000 tons from a coal-fired plant of a similar capacity. And while some radiation would be created, there would be none of the lethal radioactive wastes formed when fission reactors split uranium atoms.
Lighting The Fire Fusion occurs when the cores of hydrogen atoms--which naturally repel each other--are compressed so tightly they fuse. This produces new atoms of helium while liberating enormous amounts of energy. Fuse a few pounds of hydrogen atoms at once and you can obliterate a large portion of a Pacific island, as the Atomic Energy Commission demonstrated during its 1950s-era hydrogen bomb tests. If, however, the fusion reaction could be controlled, the energy could be recovered and used to produce steam to spin the turbines of electric generators.
Wet Matches Initially, scientists believed the most difficult task would be achieving the 100 million-degree temperatures at which deuterium and tritium--two rare forms of hydrogen--fuse. Using ordinary hydrogen was ruled out because it would require temperatures far above those that existing materials could contain. Using deuterium alone was considered, but also ruled out because of temperature limits.
After spending an estimated $50 billion of taxpayer money, scientists have learned how to light the fire. The problem is to keep it burning. Just as the flame atop a candle dances in a breeze, a fusion reaction is buffeted by currents that develop inside the magnetic "bottle" that contains the swirling plasma.
Year after year, projected dates for the debut of fusion generators moved further into the future. "In 1980, the U.S. government determined that the energy crisis was over and that the development of new energy technologies would be left to the private sector," says Stephen Dean, president of Fusion Power Associates, a fusion education group based in Gaithersburg, Md. In 1996, the Department of Energy (DOE) snuffed out the candle completely when it cut off U.S. contributions to the International Thermonuclear Experimental Reactor (ITER). The $14 billion project will instead be built with Canadian, European and Japanese support, and most likely be constructed near Clarington, Ontario. Although the Canadian government has begun work on an environmental impact statement, no date has been set for the groundbreaking.
With no fusion funding in sight, young scientists in the United States turned their backs on the science that undergirds fusion machines--plasma physics. Last year, the National Research Council (NRC) soberly reported that among the 1300 physicists in the 25 leading university research departments, only three young scientists, holding the rank of assistant professor, were experts in plasma physics.
A New Dawn This year brought the first signs of improvement in more than a decade. In February, Raymond Orbach, chancellor of the University of California at Riverside, won congressional approval as the new director of the DOE Office of Science. A professor of physics, Orbach previously held visiting professorships in England, France and Israel. The fusion community sees his appointment as exactly the combination of technical and diplomatic skills the United States needs to build bridges after turning its back on ITER. "President Bush is particularly interested in the potential of ITER, and has asked us to seriously consider American participation," Secretary of Energy Spencer Abraham told the Conference of G8 Ministers who met in Detroit in May.
The DOE also has promised researchers more money, offering to increase the roughly $225 million-a-year budget for the Fusion Energy Science Program to as much as $377 million by 2006.
There had been optimism about fusion energy generation before, but this time it is more firmly grounded in science. "Theory and modeling are now able to provide useful insights into instabilities and to guide experiments," the NRC concluded in its 2001 study of plasma physics. "Many of the major experimental and theoretical tools that have been developed are now converging to produce a qualitative change in the program's approach to scientific discovery."
More to the point, the chief limitation of the first generation of fusion machines--the inability to control turbulence in a roiling mass of magnetically confined plasma--has begun to yield to technical solutions, explains Miklos Porkolab, director of the Massachusetts Institute of Technology's Plasma Science and Fusion Center in Cambridge. "We have shown that, in principle, it is possible to eliminate turbulence," he says. "To me, this is just a mind-boggling achievement. With adequate federal funding, a prototype nuclear fusion reactor could be tested within 30 to 40 years. A commercial reactor could be deployed by the middle of the century."
Every nuclear power plant now in operation produces neutrons and PU.
"Every nuclear power plant now in operation produces neutrons and PU."
The point I wanted to make, the problem of illicit PU-239 production does not go away. The reaction path for the production of Pu-239 is:
U-238 + n yields U-239
U-239 yields Np-239 + Beta
Np-239 yields Pu-239 + Beta
To optimize the production of Pu-239, the U-239, Np-239, and the Pu-239 must be removed before further neutrons are added. I believe it is possible (in a fusion reactor) for them to be removed almost as soon as they are created.
"We have shown that, in principle, it is possible to eliminate turbulence," he says. "To me, this is just a mind-boggling achievement. With adequate federal funding, a prototype nuclear fusion reactor could be tested within 30 to 40 years. A commercial reactor could be deployed by the middle of the century
That above was what the article actually said . They haven't solved anything, just "it's possible in principle". To me that just sounds like more bureaucratize for "we need more money".
The writer could use a course in predicate logic. Or not. Probably a waste of time and money.
Hype for plasma physics to get more government money. As regards modelling, I quote: "To get results from MHD modelling takes the most brilliant mathemetical physicists -- to believe them requires the biggest idiots."
Identify a place that is dry and geographically stable --Nevada comes to mind. Secure the place well from potential terrorism, like put it on a military base. And pay the state citizens enough so that they receive a benefit that overcomes all the phony histeria that they will have to live with from people who are basically trying to stop new power sources for environmentalist reasons. (I.E. to stop growth.)
The solution will mean some real estate will be forever (several generations for sure) unusable for anything else, but there is space available.
Very interesting!
There's a lot of exciting research going on the the field of nuclear fusion today and of course most of it is very difficult for a layman like myself to understand. (My background is in history and social sciences.)
Fascinating nonetheless though.
And we can only hope it promises real energy independance for both America and the rest of the world.
Everytime I read about new research being done in the field of nuclear fusion, I am filled with hope for the future.
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