Nov. 10, 2011 at 9:43 PM ET
The standard joke about nuclear fusion is that it's the energy technology of the future, and always will be. Well, fusion is still an energy option for the future rather than the present, but small steps forward are being reported on several fronts. That even includes the long-ridiculed campaign for "cold fusion."
Efforts by the Italian-based Leonardo Corp. to harness low-energy nuclear reactions (the technology formerly known as cold fusion) have reawakened the dream of somehow producing surplus heat through unorthodox chemistry. Today, Pure Energy Systems News reported that Leonardo's Andrea Rossi signed an agreement with Texas-based National Instruments to build instrumentation for E-Cat cold-fusion reactors.
Will this venture actually pan out? The E-Cat reactors are so shrouded in secrecy and murky claims that it's hard to do a reality check, but most outside experts say that the concept just won't work.
Some observers are similarly pessimistic about the other avenues for fusion research. The basic physics of the reaction is well-accepted, of course. You can see the power generated when hydrogen atoms fuse into helium when you look at that big ball of gas in the sky, 93 million miles away, or when you watch footage of an H-bomb blast.
But no one has been able to achieve a self-sustaining, energy-producing fusion reaction in a controlled setting on Earth, even after more than a half-century of trying.
Researchers had hoped to reach that big milestone, known as ignition, at the $3.5 billion National Ignition Facility by the end of 2010. But in last week's issue of Science, Steven Koonin, the Energy Department's under secretary for science, was quoted as saying "ignition is proving more elusive than hoped" and added that "some science discovery may be required" to make it a reality. (Coincidentally, Energy Secretary Steven Chu announced this week that Koonin will be leaving his post.)
The big challenge is to tweak all the factors involved in NIF's super-laser-blaster system to maximize the energy directed on tiny pellets of fusion fuel, and minimize the loss of energy through tiny imperfections or interference. "We're at the end of the beginning," NIF's director, Edward Moses, told Science.
How much longer will it take? The new director of Lawrence Livermore National Laboratory, where NIF is headquartered, told the San Francisco Chronicle that he was convinced the facility would attain ignition "in this fiscal year" — that is, by next October.
If NIF hits that schedule, it'll be way ahead of the world's most expensive fusion experiment, the $20 billion ITER experimental project in France. ITER is taking the most conventional approach to creating a controlled fusion reaction, which involves magnetic containment of a super-hot plasma inside a doughnut-shaped device known as a tokamak. The European Union and six other nations, including the United States, have divvied up the work load with the aim of completing construction in 2017 and achieving "first plasma" in 2019.
Right now, Oak Ridge National Laboratory and US ITER are testing a fuel delivery system that would fire pellets of ultra-cold deuterium-tritium fuel into the plasma.
"When we send a frozen pellet into a high-temperature plasma, we sometimes call it a 'snowball in hell,'" Oak Ridge physicist David Rasmussen said in an ITER report on the tests at the Dill-D research tokamak in San Diego. "But temperature is really just the measure of the energy of the particles in the plasma. When the deuterium and tritium particles vaporize, ionize and are heated, they move very fast, colliding with enough energy to fuse."
The tricky part has to do with shaping the pellets just right to produce the desired reaction. When it comes to snowballs in hell, the devil is in the details.
The politics of ITER is just as tricky as the technology. Considering the economic problems that are afflicting the world, and Europe in particular, will there be funding to support the development timeline? Last month, one of the leaders of the European Parliament's Green bloc called ITER a "ticking budgetary time bomb."
Wiffle-Balls and other wonders
Smaller-scale fusion research efforts, meanwhile, are getting a lot of good press. For example, the Navy-funded experiments in inertial electrostatic confinement fusion, also called Polywell fusion, are continuing at EMC2 Fusion Development Corp. in New Mexico. The latest status report for the $7.9 million project says that the test reactor, known as a Wiffle-Ball because of its shape, "has generated over 500 high-power plasma shots."
"EMC2 is conducting tests on Wiffle-Ball plasma scaling law on plasma heating and confinement," the brief report reads.
The Polywell system is designed to accelerate positively charged ions inside a high-voltage cage, in such a way that they spark a fusion reaction. If enough of the ions fuse, the energy could exceed the amount put into the system.
In the past, leaders of the EMC2 team have told me that their aim is to build a 100-megawatt demonstration reactor. Nowadays, EMC2 is more close-mouthed about their progress, primarily because that's the way the Navy wants it. But the report about 500 high-energy plasma shots brought a positive response from the Talk-Polywell discussion board, which has been following EMC2's progress closely. "I'd be drunk by now if those were shots of whiskey," one commenter joked.
Privately backed efforts are moving ahead as well: Last month, Lawrenceville Plasma Physics reported reaching a record for neutron yield with its "Focus Fusion" direct-to-electric generator. And this week, Canada's General Fusion and its magnetized target fusion technology were featured in an NPR news package.
"I wouldn't say I'm 100 percent sure it's going to work," General Fusion's Michel Laberge told NPR. "That would be a lie. But I would put it at 60 percent chance that this is going to work. Now of course other people will give me a much smaller chance than that, but even at 10 percent chance of working, investors will still put money in, because this is big, man, this is making power for the whole planet. This is huge!"
Is it a huge opportunity, or a huge waste — especially considering that the energy technology of the future will have to compete with present-day technologies such as solar, wind, biofuel and nuclear fission? Feel free to weigh in with your comments below.
Update for 3:40 p.m. ET Nov. 11: Some commenters have rightly pointed out that there are many other nuclear fusion and high-energy plasma initiatives under way, including the Z Machine, a huge X-ray generator at Sandia National Laboratories in New Mexico. The journal Science quotes Sandia researchers as saying the machine could be used to start testing the feasibility of pinch-driven fusion, but conducting a definitive test would require a far more powerful machine.
Science also notes that some researchers suspect NIF's indirect approach to laser-driven fusion, in which fuel pellets are placed inside a pulse-shaping cylinder known as a hohlraum, may not be as efficient as it needs to be. Research groups are investigating direct-drive laser fusion at the Laboratory for Laser Energetics in Rochester, N.Y., and the Naval Research Laboratory in Washington.
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