Energy Quest : Fusion--Some Still Like It Hot
At the center of a thicket of oaks, maples and sycamore trees three miles northeast of Princeton University, 115 physicists, 200 engineers and 400 technicians have been toiling quietly in a cluster of boxlike buildings, inching toward a goal that has long tantalized scientists.
“Site C” is home to the Princeton Plasma Physics Laboratory, the premiere fusion program in the United States. For almost 40 years, scientists here have been at the vanguard of an agonizingly slow but alluring effort with a wildly ambitious goal--to solve the world’s energy woes.
They aim to do that by harnessing on Earth the same process that fires the sun, and in a football field-sized workroom filled with tangles of copper tubing, stainless steel tubs and humming machinery, they claim to be just inches away from showing that fusion can become a viable energy source.
View of Next Century
Fusion die-hards claim that by the middle of the 21st Century, the process will be used to heat our homes, light our cities, irrigate our deserts, clean our sewage--even help cure cancer.
“From a technical point of view I think it is a certainty that it will be made to work one way or another,” said Harold P. Furth, the frizzy-bearded, quintessentially professorial head of the Princeton lab. “It is so obvious . . . It’s like asking somebody in the 18th Century how sure are you that people are going to fly. (They) don’t quite know how yet, but it is pretty clear that it can be done.”
With nuclear fusion, two atoms are squeezed together at inferno-like temperatures to make a new atom, and in doing so a sizable burst of energy is released. But before that can happen, the atoms--usually a type of “heavy” hydrogen called deuterium--must be compressed with a strong enough force to overcome the fact that they are laden with electrical charges that repel one another. At Princeton, the compression is done with the aid of giant magnets.
So far, the quandary for the scientists has been that the process requires more energy than it produces, making it impractical for anything other than a scientific experiment.
Source of Excitement
It was because of this hitch that two chemists shocked the world in March when they coolly announced that they had produced energy through fusion with a simple table-top device. The two, B. Stanley Pons of the University of Utah and Martin Fleischmann of the University of Southampton in England, have claimed to accomplish their feat without the high temperatures, without the huge magnets, without any costly machinery at all. Operating on a shoestring budget, the men used a flask, a sliver of metal and an over-the-counter battery.
Their seemingly fantastic claim of achieving a nuclear reaction at room temperature has thrown the normally staid scientific community into a frenzy. Some of the world’s top researchers say the Pons-Fleischmann claims have merit, but many more are calling it folly. With each passing week, more and more scientists have abandoned attempts to duplicate the work, turning their attention once again to the more traditional programs like Princeton’s.
Most scientists agree that Pons and Fleischmann, with their credibility on the line, must come up with clear evidence soon that their work is sound. The two chemists are scheduled to appear at scientific meeting in Los Angeles today.
“I doubted from the beginning that it was true,” physicist Don J. Grove, a member of the Princeton team since 1954, said of the Pons-Fleischmann claim. “But I was not unhappy to have it come up. I can’t go one inch at a cocktail party without people wanting to know about it. That just gives me the opportunity to tell them why I think fusion is such a good thing. . . . A lot of people know the word now, know what it means, and they didn’t before.
Chance for a Joke
“While it’s unfortunate if it turns out that some segment of the scientific community may be caught with its pants down, at least it isn’t physicists,” joked Grove, who originally came to Princeton for six months to draft a design for a fusion power plant for Westinghouse. He never left.
The doubting of Pons and Fleischmann has been so extreme in some quarters that scientists have even resorted to circulating cartoons and jokes mocking the two. At Princeton, researchers gleefully displayed a parody of a press release trumpeting the greatest find yet in the quest for fusion--this one using the common potato. The announcement quotes a Dr. Spuds McKenzie, research director of the newly formed Potato Fusion Division at Oak Ridge National Laboratory in Tennessee.
According to McKenzie, the potato test, conducted in two reactor units, featured an ordinary household spud wrapped in a thin palladium-like foil--mimicking the metal used by Pons and Fleischmann--and a second, unwrapped potato. Like Pons and Fleischmann’s, the “Potato Experiment” produced more heat than was needed to run it. “In fact,” the release proclaimed, “over one kilowatt was observed to be emitted judging by the acoustic emission from one of the researchers (‘Ouch’).”
The announcement ended with the promise that “further work is in progress, including tests on ‘Big Boy’ tomatoes.”
Cautious Viewpoints
Despite such mockery, scientists such as Furth and Grove are cautious when asked about the Utah experiment, saying that no scientist worth his salt should wish that the fusion-in-a-flask claim is a hoax.
“It can happen in any field, particularly something that has the potential of this,” Groves said. “It’s pretty tough to keep your enthusiasm in check if you think you’ve got the answer to the world’s energy problems. I’m sympathetic.”
What’s at stake in fusion research is more than a matter of reputation. Fusion scientists are competing for shares of an ever-shrinking pie of government money. The U.S. Department of Energy has cut funds for fusion research from a peak of about $460 million a year in the early 1980s to about $350 million last year. At Princeton, where the largest share of the money goes, budget cutters have trimmed spending from about $140 million to $102 million during this period.
In addition to Princeton, the government underwrites programs at the Massachusetts Institute of Technology, Oak Ridge and UCLA, among others.
At Princeton, much of the work takes place inside a mammoth, 50-foot-tall mass of machinery known as a “Tokamak.” An acronym for the Russian words for “torus,” “chamber” and “magnetic” the Princeton version of this Russian invention cost $314 million when it opened in 1982.
Just Like a Movie
The Tokamak is run from a nearby central operating area straight out of a science-fiction movie. Scores of computer screens are stacked wall-to-wall. Warning signs are everywhere, from more serious alerts of high voltage danger to the more benign--signs that advise workers to plop their food garbage into covered trash cans.
Six hundred feet of yellow concrete-floored tunnel leads to the cavern where the Tokamak is located, a space so huge that its four walls are marked with giant directional signs--north, south, east and west. The Tokamak itself is so large that the room had to be constructed around its base. More than three dozen scientists and technicians are needed to monitor the machine when it is operating.
The program at Princeton began in 1951 under the title “Project Matterhorn,” so named because its then-director liked to climb mountains. Like others around the nation, scientists were drawn to the Princeton experiments because of fusion’s infinite possibilities.
Unlike fission, in which huge amounts of uncontrolled energy and radioactivity are created by splitting--rather than joining--atoms, fusion has long been seen as offering a clean, danger-free and endless supply of fuel. It has been touted as a cure-all for such modern-day problems as acid rain, greenhouse warming trends, and the dwindling supply of fossil fuels.
Plenty of Materials
Even better, the raw materials needed to produce the reactions are bountiful. The heavy hydrogen used in fusion is found in common sea water. Tritium, another raw material, is found in the metal lithium, which can be easily produced.
But so far, transforming the work done in fusion experiments into a process that can run the nation’s power plants remains an elusive dream.
The work now being done is aimed at a milestone called “break-even”--that point at which energy used is equal to energy produced.
“Well, we are prudently optimistic,” said Furth, a smiling man who speaks in a slow, clipped cadence. “We do think maybe by 1990, we can reach this break-even point.” A scientist to the core, the bespectacled, slender Furth is not given to overstatement. Even though he has been at the forefront of fusion research for years, frequently giving speeches and writing papers extolling its merits, he’d clearly rather be left alone to work in his lab. Talking to the media and having his photograph taken are little more than necessary evils, “part of the show business” side of promoting Princeton’s program.
“We tend to be a little shy,” said Furth, who joined the Princeton project more than 30 years ago, devoting virtually all of his professional life to the quest for a clean and plentiful energy supply. “We like getting a little attention every eight or 10 years when we do something that is really well-proved . . . when we do something really good.”
Reason for Applause
Princeton scientists earned plaudits in 1986, when they produced temperatures of 200 million degrees centigrade inside the Tokamak reactor. Since then, they have added 150 million degrees more to aid the fusion reaction. By comparison, the core of the sun is measured at about 15 million degrees.
But producing such extreme temperatures requires as much electricity as it takes to power all of the lights in central New Jersey. To run the machine for even a few seconds takes 30 million watts.
What Furth and the other scientists must do to reach their magic threshold is improve the Tokamak’s ability to confine the hydrogen atoms so that they will overcome their natural electrical repulsion and fuse.
Even as late as 1970, the goal seemed wildly futuristic. The energy being produced by the Princeton machinery was many millions of times smaller than the energy used. By 1975, the ratio of energy in to energy out was down to 100,000. And, today researchers are within striking distance of break-even.
But even with break-even, the fusion machine would not produce enough energy to make it economical for widespread use. And so, the researchers are looking beyond their current Tokamak to the next generation of equipment--something they call the Compact Ignition Tokamak.
With that $450-million machine, they hope to reach “ignition,” where fusion will continue to occur on its own once it is started.
Like Building a Fire
“It’s like starting a fire in your fireplace,” said Anthony DeMeo, a physicist who serves as spokesman for the Princeton program. “You strike a match and the thing starts . . . and then it burns forever as long as you keep putting wood in. . . . It’s just dry wood that burns.”
In contrast, the current process works as if the wood is wet. “Now we have to keep lighting the match again,” DeMeo said. “You have to keep the flame under the wet wood because it will not” burn on its own.
After that, there are other plans. An actual test reactor, similar to a power plant, would be built by about the year 2000 in a joint venture with the Soviet Union, Japan and Europe. The facility probably would be in Europe or Canada.
Ten years later would come a prototype power plant, followed by the first in a network of commercial plants around the country. Furth figures that fusion power will not become a staple of daily life until sometime around the year 2040.
He and his colleagues don’t mind that the road to commercial fusion power is long. But they do mind that their ability to make headway too often depends on shifting political winds.
“Yes, there seems to be a 20-year cycle,” Furth said, smiling. “It’s what a psychiatrist would call a manic-depressive cycle--five years manic, 15 years depressive.” He explained that the manic phase happens each time there is public awareness that the world is depleting its supply of fossil fuels and the government responds by loosening its purse strings. That happened in the late-1950s and again in the late-1970s.
‘Stagnation Phase’
“And then we go into a stagnation phase as we have been in since 1980,” Furth said.
The Princeton researchers are not hopeful that the rush of publicity surrounding the Utah fusion experiment will be enough to break the cycle. They worry that it might hurt them.
“It’s possible that . . . everybody has been reminded how great fusion is, how wonderful it would be and so they will say, ‘Gee, the warm fusion approach has done pretty well and is slowly delivering the goods and so why not be serious about it instead of having all these ups and downs,’ ” Furth said.
Ever the cautious scientist, however, Furth was quick to add, “Other things are possible too.”
QUEST FOR FUSION IN A MAGNETIC DOUGHNUT Hot Fusion in a Tokamak Reactor
The most successful hot fusion machine is the doughnut-shaped tokamak reactor used at Princeton and elsewhere, seen at right.
For hot fusion to occur, deuterium atoms must be heated to a high temperature and compressed, forming ions in which electrons have been stripped away. The result is a gas called plasma.
The reactor uses two opposing magnetic fields to compress
confine
the plasma so that fusion can occur. Electric currents, shown here by arrows, run through coils circling the doughnut and creating opposing magnetic fields inside.
The Reaction
Two deuterium ions fuse together to form a helium-4 ion. To get rid of excess energy, the helium-4 normally ejects either a neutron (leaving behind a helium-3 ion) or a proton (leaving behind a tritium ion).
