Tihiro Ohkawa. “Ohkawa has had a lot of the fundamental ideas that have come out in fusion in the last ten years. In fact, most of them.“
It’s like building a house or a bridge, insists Tihiro Ohkawa. He sits at a conference table in his office at General Atomic’s Torrey Pines complex, drawing from time to time on a briar pipe. Outside a light rain is falling; from the windows of Ohkawa’s ground-level office you can see it drifting downward like mist. Water from the eves drips into the bushes a few feet away from the glass. You start with a design. he continues, and you try to make it as strong as possible. “You look at what its limitations are. And then you try to remove those limitations. The rest is straightforward. ...”
Ohkawa: "If you’re talking about when I do my best scientific work, probably it’s sometime when I’m asleep.”
Ohkawa is not in the business of building houses or bridges. His specialty is magnetic bottles, containers whose “walls” are magnetic fields. As the head of General Atomic’s controlled fusion research program, he has been working for the last twenty years to solve one of the most elusive riddles of modem physics; the controlled conversion of hydrogen into helium, a process which heretofore has taken place only in the middles of stars. The problems to overcome have been formidable. In particular, the reaction takes place only at temperatures in the neighborhood of 100 million degrees centigrade. How to heat hydrogen to this temperature and then effectively contain it are questions which have defeated scientists around the world for the last thirty-five years.
Ohkawa. General Atomic, a division of General Dynamics Corporation, had been actively researching the fusion process since 1959.
But if the problems are formidable, the possible gains make them well worth trying to solve. Unlike fission (the process that fuels today’s nuclear power plants), which involves the splitting of atoms, fusion involves the joining of them. Also unlike fission, fusion produces no radioactive waste material. And hydrogen is plentiful on earth—it’s a prime component of sea water. If a controlled fusion reaction could be harnessed, say, to generate electricity, the world’s energy problems would be over for roughly the next 10 billion years.
Ohkawa and Doublet III. Doublet has become the vanguard of fusion research not only at General Atomic but around the world.
Ohkawa smiles faintly from across the conference table, and leans forward and raps the bowl of his pipe sharply on a glass ashtray. “At the moment, controlled fusion is not really technology-limited,” he says. It is February 23, 1979. Ohkawa and his assistants are one of four groups nationwide racing to be the first to control a fusion reaction. Nearly everyone involved thinks the race will be over by 1981.
Schematic of Doublet
Ohkawa is a short, wiry man, with a broad forehead and graying hair. He is modest and soft-spoken. One of his top assistants, John Gilleland, says of him, “Ohkawa has had a lot of the fundamental ideas that have come out in fusion in the last ten years. In fact, most of them.“ But Ohkawa would never make such a claim, at least not publicly. He shrugs off most questions about his research and compares it to something mundane—like building a house. A native of Japan, he speaks English well but in phrases sometimes linked more by logic than by grammar. He has at least three different laughs, one of which is a full-bodied chuckle. Another is a short, nervous laugh that many say is characteristic of the Japanese. His third laugh is not really a laugh at all, but a bemused expression that occasionally appears when he is regarding someone with his luminous, dark eyes.
Diagnostics used on Doublet
Ohkawa came to General Atomic in 1960, when he was thirty-one years old. In 1959 he had been working in Geneva, Switzerland, for an international committee on nuclear research; prior to that he was an associate professor of physics at the University of Tokyo. He was an ardent skier as a younger man, and says of the time he spent in Geneva, “Good skiing place, the Alps.” He remembers writing a postcard to his friend Donald Kerst, then a key figure in General Atomic’s fusion research program, telling him just how good the skiing was. Kerst wrote back that Ohkawa could ski at Mammoth if he would visit San Diego. Ohkawa accepted the offer, and soon went to work as one of the principal scientists in the fusion research program.
General Atomic, at that time a division of General Dynamics Corporation, had been actively researching the fusion process since 1959. In addition to the parent corporation’s own funds, much of the considerable money needed was supplied by the Texas Atomic Energy Research Foundation (a group of electric utility companies that hoped fusion reactors would shortly replace coal- and oil-burning electric generators). But fusion, which looked so promising in the late Fifties, soon bogged down in what seemed like insurmountable problems. How was such an extraordinarily high temperature to be reached? How would the hot gas be contained? The more intricate these problems got, the more General Atomic focused on its other major research efforts, particularly uranium fission reactors. The problems of fission reactors—primarily the fact that such reactors produce a substantial amount of waste material that emits a hazardous level of radiation for hundreds, in some cases thousands, of years—were well known, but so was most of the technology that would put them to work producing electricity. While interest in fusion dropped off. General Atomic began to develop its own brand of commercial fission reactor, called the High Temperature Gas-Cooled Reactor (HTGR), along with a smaller reactor used for training and research, known as TRIG A.
In the mid-Sixties General Atomic prepared to enter the field of commercial fission reactor construction. Among the nation 's other reactor-building companies—General Electric, Westinghouse, Babcock & Wilcox, and Combustion Engineering—they were considered a newcomer with an interesting new product. The HTGR, while more expensive to build than other fission reactors, was more efficient and produced somewhat less radioactive waste. A prototype reactor for the Philadelphia Electric Company was completed in 1967 at Peach Bottom, Pennsylvania, and orders for other HTGRs soon followed. Ironically, that same year General Dynamics decided that the expensive fission and fusion research at General Atomic had become too much of a financial drain, and the company was sold to Gulf Oil Corporation. The cost of the research and development of the HTGR alone was later put at $450 million.
Two years before the Peach Bottom reactor became fully operative. General Atomic began building its first commercial HTGR for the Public Service Company of Colorado. This reactor, located at Fort St. Vrain, Colorado, was beset with problems during its construction. Since the plant was a relatively new design, several unforseen engineering problems surfaced, and changing federal and state regulations regarding the safety of nuclear power plants in event of earthquakes and windstorms further delayed its start-up. Begun in 1965, it didn’t become fully operative until 1976.
In 1974 Gulf sold a half interest in General Atomic to Royal Dutch/Shell for $200 million. Within a year Royal Dutch/Shell set aside an additional $199 million for the company against contract losses, for by then it was clear that the HTGR program was in serious trouble. The ten or so commitments for HTGRs that General Atomic had secured over the years were melting away. Power companies, citing the high interest rates for financing long-term construction of the reactors, as well as uncertainty over future electricity demands in their areas, stalled and then gradually backed out of their promises to buy HTGRs. By early 1978 General Atomic had only three HTGR contracts left, and they were forced to cancel them. “A lot of soul-searching went on at the time.” said General Atomic’s public relations director Earl Zimmerman recently. “We eventually decided that it was cheaper to get out of the business.” Zimmerman blames antinuclear and environmental groups for contributing to the changing safety regulations which stalled construction of fission power plants and made them financially less attractive to potential buyers.
Fission research caused additional woes for General Atomic in August, 1977, when the company was accused of “losing” some seventeen pounds of uranium. Officials from the Nuclear Regulator)' Committee informed Governor Jerry Brown about the discrepancy, adding that there was no evidence of theft and that the loss could likely be traced to “overestimates, machining and scrap losses, and unmeasurable amounts bound up in equipment and pipes. ” In a statement quoted in the San Diego Union on August 3, a spokesman for General Atomic confirmed the latter, saying, “We are quite confident that there has been no loss of fissionable materials that cannot be accounted for. In the finished material there is always a certain amount that goes into the laundry (on employees’ clothing), ducts and air conditioning.” (When asked recently about the incident, Earl Zimmerman emphasized that the company has a strong interest in keeping track of exactly how much uranium it has on hand due to the high cost of the material. He conceded that some is inevitably lost in the machining process, but claims that this “dust ” poses no health hazard due to its relatively low-level radioactivity.)
General Atomic today occupies a sprawling 400-plus acres just north of the UCSD campus on Torrey Pines Road. Much of the complex is immaculately landscaped, with pine trees, shrubs, fountains, and lawns like putting greens. But the pastoral atmosphere is exploded by a tall fence encircling the complex, and the entrances are manned by security guards. A visitor must acquire two separate passes before being allowed in. one of which must be signed by a company official before the visitor can then leave. According to General Atomic, some of the reasons for the security are related to the valuable equipment which the company utilizes, and to government regulations on industrial safety in general. But some of the precautions are necessary because of the radioactive material that is manufactured there (the company does not handle bulk uranium ore but machines high-grade “fresh” uranium into rods and pellets for its reactors).
In spite of the cost of such security, the setback of their HTGR program, bureaucratic hassles, and public outcry that go with the handling of radioactive materials. General Atomic continues to develop and sell fission reactors (they also market electronic devices and a line of carbon-based artificial body parts used primarily in heart-valve operations). Predictably, when asked about the hazards of such reactors, company officials tend to downplay potential problems; after all, their business is to sell these reactors for a profit. Listening to them, it almost sounds as if storing radioactive reactor waste in such a way as to prevent it from entering the food chain permanently is a relatively small problem, of concern only to vindictive special-interest groups rather than various state legislatures. (Maine and California have passed laws prohibiting the further development of fission power plants until the question of waste storage can be resolved, and three other states are considering similar legislation. The California law is currently being challenged in court.) They repeatedly claim that current coal- and oil-burning power plants are at least as dangerous and harmful to the environment. And they scoff at what they say is undue concern over the dangers of radioactive substances. “Uranium is just another material. In my opinion, there are a lot of other materials far more dangerous,’’one official asserted recently. “There is no such thing as a perfect energy source,” another official said.
Melvin Gottlieb, director of Princeton University’s fusion research program, has put the problem in a somewhat different perspective. “All energy production has undesirable side effects,” he said in an interview in Time magazine. However, he added. “There seems to be less [undesirable side effects] with nuclear fusion than with other power sources currently in use.” That fusion reactors now loom on the horizon as a possibility is due in no small measure to another employee of General Atomic, Tihiro Ohkawa.
Scientists have been intrigued by fusion, the process that fuels the stars, ever since its basic principles became known during the 1930s. It is estimated that in the sun. 564 million tons of hydrogen is converted into 560 million tons of helium every second. The remaining four million tons is released as energy, a small fraction of which is sufficient to warm our entire planet. It is this extraordinary quantity of energy released, along with the availability of large quantities of hydrogen “fuel” on earth, that over the years has made the concept of a fusion power plant impossible to ignore. Because special forms of hydrogen. known as deuterium and tritium, are required, not all of the hydrogen in sea water can be used. But in every gallon of sea water there is about one-eighth teaspoon of deuterium and tritium. In the fusion process this quantity of material releases the energy equivalent of 300 gallons of gasoline.
Since a fusion reaction takes place only at temperatures near 100 million degrees centigrade, scientists in the early Fifties had to search for a new type of container in which the reaction could take place (the highest melting point of any known material is only 6000°F). The most promising approach hit upon was the magnetic “bottle.” Theoretically, hydrogen could be “ionized” (separated into positively and negatively charged particles) and contained within powerful magnetic fields. An electric current could then be passed through the gas to superheat it, and supposedly fusion would take place. Still, no one really knew if such a device would work (one of the first prototype magnetic confinement devices, built in 1952 at the Los Alamos Scientific Laboratory, was dubbed the “Perhapsatron”). As it turned out, the strongest electric current science could come up with for (he next thirteen years only heated the hydrogen to a few million degrees centigrade, and even at those temperatures the gas (known as a plasma in its ionized state) writhed, twisted, and generally escaped from the most elaborate magnetic bottles devised. One physicist compared the effort to trying to contain a blob of Jello in a web of rubber bands.
While some laboratories began to experiment with alternative methods of controlling fusion, Ohkawa, Kerst, and their assistants pursued the magnetic confinement approach. It wasn't easy or inexpensive: to cope with principles never before encountered by science, the group had to design new instruments; and huge amounts of electricity were needed to activate the magnetic fields and heat the plasma. But finally, in 1965, their persistence paid off. Using Ohkawa's new “multi-pole” concept (consisting of interlocking magnetic fields), they achieved the first stable confinement ever of a plasma. They didn’t yet have the capability of heating it to 100 million degrees centigrade, but they could at least get it hot and keep it where they wanted.
Shortly after that, Russian scientists, using a separate but similar approach, achieved the stable confinement of a plasma. Their machine was similar to General Atomic’s in that the confinement chamber was doughnut-shaped; a cross-section sliced out of it would have shown that the wall at any one point was a perfect circle. At the time this was believed to be the best and probably only possible shape for an effective magnetic confinement chamber. But in 1967 Ohkawa published a paper modifying his concept: the overall chamber should be doughnut-shaped, he said, but a cross section of it should look like an hourglass. He referred to this new concept as Doublet, and it has become the vanguard of fusion research not only at General Atomic but around the world.
The same year that Ohkawa published his first paper on the Doublet concept, he became director of General Atomic’s fusion research program. He had revolutionized fusion research, and apparently his contributions were not unrecognized by the company’s executive directors. “Until Ohkawa came along, these magnetic bottles didn’t work. They just didn’t work,” says John Gilleland. Gilleland, at thirty-eight, has been with General Atomic since 1970. Prior to that he obtained his doctorate at the University of Michigan, experimenting with the magnetic confinement of atomic particles. He credits Ohkawa’s multi-pole concept as being the prime reason scientists “have gone from a position of thinking that nature might not like magnetic bottles, that there might be fundamental physics reasons why they wouldn’t work, to demonstrating that the best possible theoretical bottle that anyone could ever dream of worked.”
Ohkawa himself is somewhat at a loss to explain how he comes up with such revolutionary concepts. He is an organized and efficient worker; he keeps regular office hours, and associates say his desk is always neat. When he is in town he spends most of his day on administrative work and conferences with his assistants. In the evenings, from around five to seven o’clock, he works on what he describes as the “technical” side of fusion research. “But if you’re talking about when I do my best scientific work,” he says, “probably it’s sometime when I’m asleep.” He laughs nervously, almost apologetically. “If you’re talking about some new idea or something like that, probably it will be percolating [in my mind] about three or four or five days. And you don’t know the answer, but then sometime in the night you know the answer. You’re probably half awake. And then the next morning you write it down.” He laughs again.
Ohkawa spends a good deal of time these days traveling from his La Jolla home to Washington, D.C., to brief government officials on the progress of fusion research at General Atomic. He insists that he doesn’t mind this “nontechnical” work, most of which relates to gamering government research contracts. But it leaves him little time to work on new theories or take part in experiments. Instead, he’s become something of a paterfamilias to a number of assistants who brief him in weekly meetings about the current research being carried out. “He can extract information faster than most people,” says John Gilleland admiringly. “He runs a sort of institution where he wants other guys to come to him with ideas. But when you get right down to it. Ohkawa has more ideas per day than anyone else around here. He has a different kind of brain. . . .
“I’ve interacted with Nobel Prize winners and heads of physics departments and universities, but Ohkawa is the only guy I’ve known who is always a few steps or a light-year ahead. Sometimes he says things that you don t even understand, and then after a halfday's discussion, it'll all be down on paper and you'll go off with a few theorists and try to fill in the two to twenty steps he's skipped between this model and that model.”
Current fusion research at General Atomic centers around Doublet III, the third in the series of magnetic confinement devices utilizing Ohkawa’s hourglassshaped confinement chamber. Doublet III is not a fusion reactor, which would utilize the heat generated in a fusion reaction to run a steam-driven generator in much the same way that fission reactors generate electricity today. It is simply a scaled-up test device, considered large enough and powerful enough to control a sustained fusion reaction for the first time. The $32 million machine is housed in a bright blue sheet-metal building visible from Interstate 5, looking out from the mouth of a small canyon near the Sorrento Valley business park. Utility poles on the slope to the left support a network of wires that carry in some of the massive amount of electricity needed for the experiments. A reddish metal fence topped with barbed wire encircles the building and adjoining yard, where ground squirrels can be seen running through the equipment and industrial debris: barrels, pipes, reels of cable, wooden pallets, storage tanks. In the foreground a small blue tower less than ten feet tall is the only evidence of the huge electric generator buried there. The largest motor-driven generator in California, it can provide at five-minute intervals surges of power up to 260,000 kilowatts— enough to meet the electrical requirements of a quarter-million people.
Inside the building stands Doublet III itself, a sixteen-foot-high sphere suggesting a giant peeled orange. Its center magnet is a fluted copper column weighing 180 tons. Bunches of wires as thick as a man’s arm feed current into the outer magnets, enormous D-shaped rings of solid copper. The confinement chamber forms a ten-foot-high ring within these outer magnets. During experiments the generator outside is slowly brought up to full speed; when everything is ready, switches are thrown and all 260,000 kilowatts surge towards Doublet III. At the same time numerous other capacitors and electricity-storing devices are called upon—for instance, a bank of six-foot-high submarine batteries is shorted, draining their power instantly. The total resulting jolt of current is enough to ionize the hydrogen within the confinement chamber, press it inward about ten centimeters from the chamber wall, and instantly heat it. “We’ve only been operating [Doublet III] a few months,” Ohkawa says, “so we’ve only achieved temperatures somewhere around ten or thirteen million degrees centigrade.”
To measure the temperature of the heated plasma, a laser beam is directed through it. By measuring the light after it’s been scattered by particles in the plasma, the temperature can be estimated. Paradoxically, such high temperatures do not threaten to vaporize the walls of the chamber, but rather the walls threaten to cool the plasma. “One of the misconceptions that people have about fusion,” explains Gilleland, “is that if you get something to several million degrees, isn’t it going to bum up everything and the machine’s going to fall in a puddle on the floor? It doesn’t work that way. If even a little bit of material from the wall gets back into the plasma it immediately snuffs the reaction out.” Similarly, if the confinement chamber should leak during an experiment, the plasma would instantly be cooled. At any rate, it’s non radioactive— simply inert hydrogen—and so poses no special problems.
The temperatures achieved so far in Doublet III still fall far short of the needed 100 million degrees centigrade. But within a year General Atomic will receive the first two of six neutral-beam injectors, which should go a long way towards solving that problem. These devices, at about $20 million a pair, will shoot neutrally charged, high-energy atomic particles into the plasma, heating it in conjunction with the electric current. Once all six neutral-beam injectors are operating (sometime around 1981), Ohkawa predicts that he and his assistants will be able to heat the plasma to the temperature needed for a fusion reaction (an additional ten or fifteen years will then be needed to develop a working fusion reactor). At that point, as one researcher once put it, with “fresh” hydrogen flowing into the chamber, you can “turnoff all the power except the magnets, and the gas in there will burn just like our own little sun.”
“Technically, I have a great deal of confidence that we could be the first to achieve a controlled fusion reaction," says Gilleland. “But it's related to the funding we get.” As the only private corporation in the world now involved in fusion research, some of General Atomic’s funds for that program come from its parent corporations, and some from the financial arm of a new group of electric power utilities, known as the Electric Power Research Institute. But the vast bulk of the research money comes from the government, and General Atomic must compete for it with the other fusion research laboratories around the nation: Princeton. MIT. and Oakridge, Tennessee. Both Ohkawa and Gilleland confirm that there is intense competition among labs for this money, which in the last twenty years has come to a total of about $500 million. Ohkawa says of the competition, “You could say it’s friendly but very tough.”
What do Gulf and Royal Dutch/Shell get out of all this? For the moment, very little. Since fusion reactors are a relatively long-term goal, it doesn’t make sense to sink a large amount of private money into them. On the other hand, the government has been more willing to supply funds if private institutions provide the facilities for carrying out the experiments. General Atomic's fusion research program is designed to survive on such grants, neither making nor losing any great amount of money for the present. Then, when the time comes to build fusion reactors commercially. the company will have the technological capability to do it without requiring a large capital investment.
Ohkawa hopes to build a fusion reactor eventually, although currently General Atomic has no specific plans to do so. He is now fifty years old, and such a device would be the crowning achievement of his research. Yet typically, he is already looking ahead to another possible goal of fusion research: the fusion torch. Sitting at the conference table in his office, absently holding a briar pipe that has been out for some time, he describes the concept. “Essentially now with the fusion reactor, you're talking about hydrogen at 100 million degrees centigrade providing your energy. But then the exhaust is the helium gas at that temperature.” Suddenly he stands up and walks over to his desk. After a few moments of searching, he returns with a paper clip and begins cleaning the bowl of his pipe with it. “So you can use helium gas at that temperature to decompose anything, really,” he continues, intent on his task. Abruptly he looks up, eyes full of mirth. “But first things first. You don't talk about the exhaust and things like that until you've invented the engine.”
Still, the fusion torch, if practical, is potentially one of the most important outgrowths of fusion research. Such a device could be used to break down toxic chemicals or the radioactive waste from fission reactors into basic inert elements. It is currently estimated that there are 5000 tons of nuclear reactor waste in the United States, and this figure is expected to reach 100,000 by the end of the century. The toxic sulfur compounds from the cleanest coal-burning power plants must also be stored as solid waste. In the past our government has allowed this waste simply to be buried or dumped into the oceans. But as much as we need electricity, it is clear that materials like these, which remain actively hazardous for long periods of time, cannot just be sealed away and forgotten. The possibility of leaks and accidents at various disposal sites may be relatively small, but the stakes—human health and life—are extremely high. If fusion power plants prove to be practical, as it now seems likely, they may help our culture to cope effectively with dilemmas it has been sidestepping for a long time.
“People often ask me when fusion will be available," Ohkawa says, “but I ask back the question: When do you need it? According to the U.S. government, by the end of the century we will have a fusion reactor. Then (for such reactors] to become a significant contributor to energy production will take about twenty or thirty (additional] years. It takes time to build it. So that's the government’s time scale, but I feel if the country wants it, then probably you could accelerate it by accelerating the work. Of course you can’t have it tomorrow. But when these new technologies become practical is often due to when the country or society wants it, rather than when the scientists invent it.”