He shared this ability with several personalities described in this book, such as Richard Feynman, Robert Oppenheimer, Hans Bethe, and Freeman Dyson himself. That’s one of the reasons the paths of these men kept crossing. Making frequent jokes, Teller had a brilliant idea every sixty seconds or so. They worked well together as a team—Teller triggering a train of thoughts and Dyson embodying the ideas in equations. Teller, like Richard Feynman, possessed a strong intuitive grasp of physical phenomena, while Dyson possessed the complementary rigorous mathematics needed to crystallize a concept quantitatively.
That summer Dyson and Teller were part of a ten-person group designing a safe reactor. Safe in this case meant not merely “engineered safety”—providing a number of redundant shut-down mechanisms under a variety of emergency scenarios. True safety, or inherent safety, holds to a higher standard. Reactors would be inherently safe only if there were no conceivable sequences of events in which the control system for the reactor, or a stupid or even malicious human operator, could unleash a catastrophic chemical explosion or meltdown of critical components.
An inherently safe reactor would be safe even in the hands of schoolkids. No matter how you spun the dials or what you did to the control panel with a crowbar, the reactor would still shut down. Teller was insistent on inherent safety. Only if this were achieved, he argued, could reactors become a large, efficient, and trustworthy part of society’s energy infrastructure.
CHILDPROOF REACTORS
Freeman Dyson’s career is manifestly linked to the instability of fissionable nuclei. Uranium is number 92 in the periodic table, the heaviest naturally occurring element. But an element can exist in several forms, or isotopes, depending on how the nucleus is stocked. Both uranium-235 and its slightly heavier and much commoner cousin, uranium-238, contain a complement of ninety-two protons, the positively charged subnuclear particle. But U-238 has three more neutrons (the neutral subnuclear particle) than U-235; the number to the right of the U is just the sum of the protons and neutrons.
All these protons and neutrons are packed into a wiggly little ball, the nucleus, which has a volume only a fraction that of the atom as a whole. One of the reasons the uranium nucleus wiggles is that it can’t quite properly accommodate its cargo of protons and neutrons. Like a restless sleeper tossing and turning, U tries to find a comfortable position. Both uranium isotopes are fitfully active. In fact, they are radioactive; that is, they vibrate until small fragments come flying out, leaving behind a more stable consignment of protons and neutrons. In this process the parent atom changes its identity. It is now a different, lighter chemical element. It’s not uranium anymore.
U-235 has another means of expressing its agitation. It can indulge in the process called fission. A passing solitary neutron of just the right energy, if it intrudes upon the nucleus, can unleash a miniature cataclysm. The U-235 nucleus sunders in half, creating such daughter nuclei as iodine, strontium, and cesium. Among the debris will be two or three energetic neutrons that can seed further fission of more U-235 nuclei. These fissions, in turn, release still more neutrons that can pry apart further nuclei, and so on. The result is a sequential breakdown.
Such a chain reaction is what makes both nuclear bombs and nuclear reactors work. In reactors the fission is controlled and the liberated energy used to make electricity. In bombs the chain reaction is uncontrolled and the surplus energy is used to make destructive pressure, fire, and radiation. In a bomb the energy stored in U-235 nuclei is extracted in a fraction of a second. At a reactor the U-235 in a fuel rod can be used over several years. The goal is to moderate the chain reaction so that it releases as much energy as you need to make electricity right then. In a bomb the goal is to encourage the chain reaction to double and redouble its propagation as quickly as possible before the bomb blows itself apart.
If Dyson had worked at Los Alamos the summer of 1945 his concern would have been for nuclear bombs. But at La Jolla in the summer of 1956 his concern was for nuclear electricity. Why do we want to handle radioactive and fissile materials at all? Nuclear materials are nasty. The spent fuel rods, in which many of the U-235 atoms have, in the course of nuclear reactions, been replaced by even more radioactive daughter atoms, are so hot when pulled from the reactor that they would melt if they weren’t quickly placed back in a pool of cooling water. The absence of that water is what worsened the accident at the Japanese reactors in the wake of the huge earthquake and tsunami in 2011.
So for making electricity, why not stick to the old reliable fuels, like coal? Why invest the billions of dollars needed to start up a uranium furnace? Putting aside for the moment the virtue of uranium’s not emitting clouds of climate-changing carbon dioxide or pollutants, the development of the nuclear industry got down to this: a kilogram of nuclear fuel surrenders a million times more energy than a kilogram of coal.
Therefore with the prospect of plentiful electricity, derived from relatively cheap fuel, producing very little pollution, many scientists were eager to push ahead. That’s why Dyson, the quantum theorist, and bomb makers such as Teller, Taylor, and de Hoffmann, were cheerfully on hand in the schoolhouse. What they accomplished that summer was to rethink the way in which the subtle control mechanisms work together inside a reactor.*
It was fitting that Dyson and his friends were working in a schoolhouse, because here they were, grown men all, but schoolkids again, trying to learn by doing. Some of their time had been spent at picnic tables out back. Their school project was to design an inherently safe reactor. If they were kids they surely would have gotten stars put next to their names.
Edward Teller was the dominant personality. He fought fiercely, even angrily, for his ideas. But then he would calm down, and come up with another scheme. Few of the participants liked Teller’s political views—the Oppenheimer security hearings were only two years in the past—but everyone liked Teller anyway.7
At summer’s end Dyson made a day trip to Tijuana, where he was bitten by a dog. Not wanting to take any chances catching rabies, Dyson underwent the painful treatment. Teller stayed with him for this period. Dyson was grateful.8
These three-month volunteers at what was essentially a nuclear summer camp did something rare in the world of high technology. They and their full-time General Atomic collaborators would design, blueprint, build, and sell a new type of reactor, all in the space of three years. The reactor Teller and Dyson had helped design that summer was called TRIGA, for Training, Research, Isotope production, General Atomic. It was destined to be one of the bestselling reactor models in history, with seventy units later installed in two dozen countries spread across five continents.9 The prototype unit operated for forty years and was given a historical designation. Another early unit became the first working reactor in Africa.
The ceremony marking the debut of TRIGA as a commercial product and the dedication of the new headquarters building for General Atomic occurred with great fanfare a few years later. The guest of honor was Niels Bohr, who, in the 1940s, had tried to persuade President Franklin Roosevelt and Prime Minister Winston Churchill to share bomb secrets with the Russians as a way of mitigating mistrust. Now he was arguing that the West and East should share reactor secrets, partly as a practical effort to speed up reactor development and, perhaps more importantly, as a gesture of trust and peaceful intentions.
At this time the phrase “peaceful use of atomic power” could mean many things, including the use of nuclear bombs to excavate canals or to mine minerals. In practice atomic power meant the generation of electricity. Many hoped, at least in the late 1950s, that nuclear-derived electricity would be “too cheap to meter.” This cornucopia would transform cities and raise up poor nations. Arthur Eddington, whose book on space and time had so inspired Dyson as a boy, prophesized in another book that subatomic power would one day transform society. It could offer a great supply of cheap energy, but it also posed a danger, since it might enable destructive forces on a large scale.10 Dyson always kept this duality
in mind.
On the day of the General Atomic dedication, Dyson was granted a great privilege: a stroll along the nearby beach with Bohr, just the two of them. Bohr was famous both for his philosophical discourse and for the fact that he often spoke very softly and in a mumble, making it hard for others to hear him. And so it was this day when Dyson leaned in to hear the great man’s words. Dyson, almost as if he knew already about the issues that would occupy so much of his time over the coming decades, issues like curbing nuclear weaponry, understanding the Russian point of view in international diplomacy, and harnessing technology, suspected that the Danish sage had a storehouse of useful insights. Dyson strained to catch Bohr’s words, but most of them were blown away by the wind.11
NOT FUN ANYMORE
Dyson had been exhilarated by his brief foray into engineering. He considered his schoolhouse summer as one of the turning points in his life. He had learned, to his surprise, that he could apply science to practical ends.12
Nevertheless, years later, after he had time to gain some perspective on the multibillion-dollar industry he had helped launch, he came to see the history of nuclear power as a tragedy. His reservations about what happened can be sorted into categories of concerns over specific critical issues, issues that haunt energy policy to this day.
Safety. Avoiding catastrophe should be at the heart of all engineering efforts, Dyson felt. TRIGA had been designed with inherent safety as the main goal. General Atomic sold plenty of their little training reactors, but they also wanted to sell billion-watt power plant behemoths as well. General Atomic’s contender at the heavyweight level was called the High Temperature Graphite Reactor (HTGR). Its chief opponent was the Light Water Reactor (LWR). Dyson asserted that HTGR, with its much larger core, was a thousand times safer than LWR, at least against the possibility of a meltdown of the fuel assembly.13 The hitch was that the HTGR cost more and took up more space. Teller and Dyson argued, long before the disaster at Chernobyl, that safety, and along with it public trust, should override other factors in sustaining a healthy nuclear power industry.
Bandwagon Effect. What the navy wants the navy gets, and what they wanted in the 1950s was nuclear propulsion, allowing submarines to run further, longer, quieter, and deeper than with diesel power. In submarines space is at a premium, so a compact reactor core is desired. Admiral Hyman Rickover’s zealous pursuit of a nuclear navy provided the construction incentive the reactor industry needed. But it also favored the small-core LWR layout over the larger-core HTGR layout in the competition for reactor design.14 Compactness was allowed to trump safety.
Economy of Scale. In embracing high technology, companies seemed to favor a larger-is-better attitude, especially in the electricity business. This tendency toward gigantism was reaching its peak just as the reactor business was taking off in the 1960s. For many years it was indeed true that larger power plants produced more electricity per fuel input than small plants. But largeness has its drawbacks. Larger machines can be disproportionately down for repairs; this was often the case for reactors in the 1970s and 1980s. In this way, Dyson asserted, a false economy of scale developed.
Flexibility. Not only does a large reactor needing repairs throw off the daily operation of a utility, but the construction of such an immense machine can take a decade or longer to complete, tying up financial resources, making it even harder for the power company to respond quickly to new increases (and sometimes decreases) in demand. “If a plant takes ten years to build,” said Dyson, “it is almost certainly too big.”15
Marketplace. In a free market, competition for customers by rival products should, in principle, optimize design and price. But what market is totally free from qualifications such as regulations, insider information, collusion, false advertising, and hidden costs? The environmental burden of nuclear power—the social cost of pulling uranium out of the ground, or enriching uranium, or storing the spent fuel rods—was for a long time not fully factored into the cost of nuclear power.16
Accountants shouldered aside the young inventors and scientists that might have come up with better solutions. Existing designs became rigid. New engineering concepts, the kind of thing that came out of the General Atomic schoolhouse, no longer emerged. For scientists and engineers working on reactors, Dyson laments, “Sometime between 1960 and 1970, the fun went out of the business.”17
In the summer of 1956, at least, the design of reactors had still been fun. Ted Taylor, having made his mark in building bombs, left Los Alamos to work with Freddie de Hoffmann full-time at General Atomic. Freeman Dyson headed back east for Princeton.
Something interesting happened to him on the way home. He had spent the whole summer studying controlled fission inside reactors. Now, stopping off at Los Alamos by invitation, he would study for two days how nuclear fusion unfolds inside bombs. Apparently Los Alamos wanted some advice about how tritium, a heavy form of hydrogen, was produced at reactors. Tritium is a vital material needed to create the fusion reactions that power a hydrogen bomb. So great was the lab’s need to talk to someone of Dyson’s ability that his lack of American citizenship did not stand in the way of his dropping in and being given, as part of his visit, a quick but thorough education in the physics of bombs.18 This crash course did not have any immediate consequence, but two years later his new knowledge would be valuable when he came to work on a nuclear device much larger than any reactor.
HEDDA GABLER
In Henrik Ibsen’s play Hedda Gabler, a headstrong, beautiful, and dangerously bored young woman, Hedda Gabler, marries George Tesman, a maladroit scholar preoccupied with his studies. The wife, forever pacing about her new home, is recharged when she makes contact again with Eilert Lövborg, a former lover and now an academic rival of her husband’s. To make matters still more complicated, Hedda and her husband are frequently visited by George’s mischievous friend, Judge Brack, who, we quickly notice, is there more to flirt with Hedda than to see George. This and a lot of other things escape George’s notice.
Freeman Dyson is not George Tesman. The scientific achievements of Dyson’s public career give us to understand that not a lot escapes his notice. What about the private Dyson?
While the Dysons lived in Ithaca, they were visited by Abraham Pais, formerly linked romantically to Verena. They were visited several times, at Freeman’s invitation, by Hans Haefeli, Verena’s former husband.19 Moreover, during the past summer, at Freeman’s suggestion, Verena in Europe visited her very own Eilert Lövborg, her “older man,” the man to whom she had pledged her heart. Freeman knew all this. What was going on? Was there a pattern at work here? This was not an inherently safe arrangement.
In the fall of 1956, back from La Jolla and reunited with his family in Princeton, Freeman settled into his new house. Purchase price: $30,000.20 Georg Kreisel, whose appointment at the Institute the year before had been made at Freeman’s urging, now became an ever more frequent visitor. What kind of man was Kreisel? Was he a potential Judge Brack?
Kreisel was a friend of biologist Francis Crick. In the Prologue to Crick’s autobiography, Crick said this: “When I met Kreisel I was a sloppy thinker. His powerful, rigorous mind gently but steadily made my thinking more incisive and occasionally more precise. Quite a number of my mental mannerisms spring from him.”21
Kreisel had a reputation as a ladies’ man and was an intimate friend of the British novelist Iris Murdoch. Supposedly he is the model for characters in several of Murdoch’s books. According to Verena, Kreisel had an affair with Brigitte Bardot. Even little Esther Dyson was captivated by the man. At one dull moment during the Salzburg summer, Esther (then five years old) had said, “I’m bored. I wish Kreisel was here.”22
Kreisel came to the Dyson home for the food and for the conversation. Verena had over the summer given much thought to resuming a mathematical career, and was prodded in this direction by Kreisel. She wanted to be a good mother, but she felt hemmed in by domesticity.23 She was cultivating an interest in photography, but t
his wasn’t enough.24
In Ibsen’s play, Hedda accidentally comes into possession of the only manuscript copy of Lövborg’s sensational new book, a book that might give him an academic edge over George Tesman. Thinking partly to cut herself off from her own past, partly to help her husband, and partly for the sheer drama of it, Hedda burns Lövborg’s manuscript.
Now in the new home on Princeton’s Battle Road Circle, Verena gathered up all copies of her Ph.D. dissertation. Going to the backyard, and with her husband looking on, she set fire to the collection. Her mathematical work went up in smoke and flame. She was symbolically declaring her allegiance to husband and children.
Things seemed to be stabilizing between Freeman and Verena. The family returned to normal life in Princeton. The kids went to school. At the annual ball given at the Institute, Freeman spontaneously got up on a sturdy table and did a Russian dance, which he’d learned on his visit to the Soviet Union the previous spring. He became a U.S. citizen, taking the oath in nearby Trenton, New Jersey. The first Christmas in the new home was celebrated with a beautiful tree, covered with real candles. Buckets of water stood by in case of fire.
Kreisel’s stomach complaints were being ignored by his doctors, he said. Only at the Dyson’s could he get the nourishment he needed. Besides, he and Verena could speak in German. She was starved for German language and literature.
Right after Christmas Freeman left for a meeting at Los Alamos. A few weeks later, Imme Jung, twenty years of age, arrived in America to take up her post of mother’s helper. Verena met her in New York harbor and brought her back to Princeton, where she quickly got to know the children and familiarized herself with the household.
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