The far-off fusion race
Posted: Friday, May 02, 2008 7:00 PM by Alan Boyle
UW-Madison |
Ions glow inside an electrostatic fusion reactor at the University of Wisconsin.
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One of the nation's top fusion researchers is worried that America is already falling behind in an energy race that won't start for 30 or 40 years.
"We're losing our lead to other countries in the world," Gerald Kulcinski, director of the Fusion Technology Institute at the University of Wisconsin at Madison, told me in his office last week.
How can that be, when most of the world's top technological powers are working together on a $13 billion nuclear fusion research project that hasn't even started construction yet? Kulcinski's answer demonstrates why an "Apollo-scale" effort to solve America's energy woes just might require more thought and time than the original Apollo moon effort.
Long-term investment
Nuclear fusion is shaping up as one of the longer-term investments in the power portfolio. For the next few decades, cleaner coal, biofuels, nuclear fission, geothermal, wind and solar power will be much bigger factors in the energy equation. Theoretically, fusion could provide clean, cheap and abundant power - that is, once scientists solve all the technological challenges associated with controlling the nuclear reaction that fuels the sun.
That's what the $13 billion ITER project is all about: By 2016, a huge magnetic containment vessel (also known as a tokamak) is to be built at a facility in France. Researchers will use that tokamak to test their concepts for sustaining a fusion reaction.
ITER's schedule calls for 20 years of research operations - leading to the construction of a prototype for a commercial fusion reactor, known as DEMO, and then actual commercialization.
NASA file |
Fusion researcher Gerald Kulcinski speaks during a
meeting of the NASA Advisory Council.
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Kulcinski is worried about the latter stages of the plan. Once ITER and its follow-up projects demonstrate that fusion power can be sustained and controlled inside a magnetic vessel, it's up to the parties in the project - the United States as well as China, Europe, India, Japan, Russia and South Korea - to figure out how best to get the power out.
"First you do the physics," Ned Sauthoff, the head of the U.S. ITER program, told me back in March. "You get yourself a burning plasma. Once you've gotten a burning plasma, then it's a matter for the politicians to decide, do they want to invest in the technology?"
In Kulcinski's view, that's the key step: "If it really works, you better figure out what you're going to do with it," he told me.
But at a time when other countries are putting more resources into fusion research, less and less U.S. funding is going into developing the technology for extracting power from a magnetically contained fusion plasma, Kulcinski said.
He said his own program has had a lot of success in magnetic fusion development, but "we're in danger of losing that now as resources get pulled away and faculty retire or die off or whatever, and we're not replacing them now with people who are looking down the road at the end product."
By the time magnetic confinement fusion is ready for commercialization, perhaps a generation from now, America will sorely miss the scientists and engineers who should have been trained for the task, Kulcinski said. "It's very ironic: The closer we get to that, the more it's collapsing," he said.
Other paths to fusion
ITER's path to fusion isn't the only one: For more than three decades, the University of Wisconsin's institute has focused its research not only on magnetic containment, but also on the other two "legs" of fusion research: laser-powered inertial confinement, which is to be developed in the United States at the National Ignition Facility; and inertial electrostatic fusion, which has been in the news recently due to the work of the late physicist/engineer Robert Bussard.
Today, the institute is funded to the tune of about $15 million a year, with 150 people working on fusion, Kulcinski said. Inertial confinement fusion currently accounts for about two-thirds of the technology development work being done at the institute.
Laser inertial confinement, which involves blasting pellets of hydrogen isotopes with precisely timed laser bursts, carries its own challenges. But the "inertial fusion folks have a much more healthy view of their end product than the magnetic fusion folks," Kulcinski said.
"There are programs that are supported to look down the road and say, 'Well, if this works, here's what our reactor will look like,'" he said.
If Kulcinski had to pick a favorite in the decades-long fusion marathon, it might well be the dark horse in the race: electrostatic fusion, which involves packing ions densely within a negatively charged grid or a cloud of electrons. He and his colleagues have been experimenting with electrostatic grid reactors for years.
"We're not even close to break-even," Kulcinski said. But the devices do produce enough high-energy protons to create short-lived radioisotopes for medical applications.
"It's an early application of fusion that has nothing to do with electricity," he said.
Kulcinski foresees a day when every hospital could have its own little fusion reactor churning out oxygen-15 and other isotopes for diagnostic purposes. (Right now they're created in cyclotrons.)
He said fusion devices could also be used to detect hidden nuclear weapons and buried explosive devices. They could even disable nuclear weapons. "We probably shouldn't discuss that, but there are ways," he said.
To the moon?
The real promise of the electrostatic devices, at least the way Kulcinski sees it, is that the electrostatic devices can be used for fusion reactions using helium-3. His group has been experimenting with a deuterium-helium-3 combination as well as with pure helium-3.
Such reactions are much cleaner than the deuterium-tritium reaction favored for the magnetic and inertial confinement devices. The D-T reaction is easier to achieve, but it produces waves of neutrons that would lead to radioactive contamination of the reactors.
Helium-3 is rare on Earth, but there's an abundance of the stuff on the moon - which is why space veterans such as Apollo 17 astronaut (and former U.S. senator) Harrison Schmitt is on the helium-3 bandwagon.
"About 40 tons of helium-3 would produce all the electricity we use in the United States in 2008. ... The moon may be a major source of new energy, and it would make the investment in the space program one of the largest payoffs in history. If in fact it all happened, this would be a huge return on taxpayers' money, as well as all the other things we do in space," Kulcinski said.
But there are lots of hurdles on the way to that nuclear nirvana: Exactly how can you scale up electrostatic fusion past the break-even point? Could future moon-mining operations really extract helium-3 from the moon and send it to Earth efficiently enough to turn a profit? Would the reaction be as clean as Kulcinski thinks it would be? Some experts have voiced grave doubts about the prospects for helium-3 fusion, or even for fusion power in general.
Answers ahead
Kulcinski predicted that each of the three potential routes to fusion will have its turn to prove itself.
"We'll do the easiest one first: That's D-T [deuterium-tritium fusion] in tokamaks. In my personal opinion, I don't think tokamaks will ever be commercially effective," he said. "I think laser fusion, or heavy-ion fusion, or X-ray fusion has a chance of being economic, probably a better chance than magnetic fusion, but it's hard to quantify."
He sees electrostatic fusion reactors using helium-3 as the best long-term option. "We could put the thing right downtown," he said.
If Kulcinski's prediction is to hold true, researchers will have to continue working on all three routes: the magnetic route, the laser inertial route and the electrostatic route.
Currently, the most promising path toward electrostatic fusion runs through Santa Fe, N.M., where a team at EMC2 Fusion Development Corp. is currently trying to validate Bussard's results. The team's leader, Richard Nebel, told me this week that it's still too early to gauge how promising the Bussard fusion device could be.
"We're getting high-power plasma," he said. "We don't have answers ... [but] we're far enough along that we know we're going to get answers."
Who knows? Maybe the dark horse in this race will pull off a surprise or two yet.
Update for 2:20 p.m. ET May 5: Nebel goes into more detail about what to expect (and what not to expect) on the Talk-Polywell.org discussion forum.
