General Atomic from the air, looking north, 1964.
Project Orion was launched officially in 1958, but its crew began to assemble in 1956. When General Atomic received the green light from John Jay Hopkins, Frederic de Hoffmann did not wait around for buildings to get built. Operating out of an office within General Dynamics' Stromberg-Carlson Division on Hancock Street in downtown San Diego, near what is now Lindbergh Field, he went straight to work, without laboratories and tennis courts but with people and ideas. In January of 1956 de Hoffmann's new company rented an abandoned schoolhouse near Point Loma, vacant since the closure of the Frontier housing project that had accommodated aircraft workers during the war. In 1943, Robert Oppenheimer and the U.S. Army had requisitioned the Los Alamos Ranch School to house the initial group of physicists assembled to build an atomic bomb. Thirteen years later, de Hoffmann reinvited many of the same nuclear physicists, and their promising younger colleagues, to gather at the Barnard Street School for the summer of 1956.
De Hoffmann's first target for recruitment from Los Alamos was Lois Iles—secretary of the Theoretical Division. According to Harris Mayer, "that's when Carson Mark hit the roof: You can take my Ted Taylor, you can take my scientists, but you can't take Lois Iles! Lois Iles did not want to work directly for de Hoffmann, but agreed to come to San Diego if she could work for somebody else, so, says Ed Creutz, "Fred then hired me, and Lois came to work for me. For the first year, Lois and I were the personnel department. In the summer of 56, she made all of the arrangements for the visitors and consultants. I think that she and I hired at least a hundred people with no other help. Lois Iles stayed on through all of Project Orion, and, as Ted puts it, "She had a lot to do with how fast everything went."
F. W. (Bill) Simpson, then the technical librarian for the AEC in Washington, D.C., was flown out to San Diego by de Hoffmann on February 28, 1956. "Fred spent most of two days with me, with a driver, showing me around town," Simpson remembers. "And he took me to the little red schoolhouse. It was dusty and cobwebby, and it looked like hell. Well, by the end of April, they had cleaned that place up, and painted things, and it was sparkling new-looking. And in the patio he had picnic benches and huge palm trees and a lot of bougainvillea and other things. They were in these huge nursery containers, looking forward to a place where they could be planted permanently. And he said, to the guy in charge of the grounds, 'I want flowers and blossoms. When people think of California, they think of flowers and blossoms. So get me some.' " De Hoffmann's instructions to Simpson, who became one of General Atomic's first employees, were to order enough books and journals so the physicists would have a working library as well as bougainvillea when they showed up. And they did.
In contrast to the Jeeps and barracks of Los Alamos, de Hoffmann insisted that transportation and accommodations be first class. "That first summer was just fabulous," remembers Ralph Stahl. "The first thing de Hoffmann did in preparation for that summer, he established a motor pool. Nice cars and drivers." Freeman Dyson wanted to see the California desert and mentioned this to his driver, who "was buying up land in El Cajon just at the right time, and didn't need to be a chauffeur anymore" and spent an entire Sunday giving him a tour. "De Hoffmann rented lovely houses for all of the visitors," says Jonny Stahl, who worked in the stenographic pool. "They weren't paid, but boy they had a lovely place to live and nice things to do for the summer." Jonny remembers deciphering Teller's Hungarian accent during the day and lengthy Scrabble tournaments at night. "I beat them all. I was very good at that. That's what I remember about that summer, that I could beat these brilliant people at Scrabble."
"Those of us who started General Atomic didn't much know the meaning of working hours," de Hoffmann explained. "We didn't know the words 9 to 5."[59] Ed Creutz, director of the laboratory that did not yet exist, helped set up the lunch tables in the courtyard of the school. "We covered these with blackboards, complete with chalk and erasers. The idea was to continue thought and discussion during lunch."[60] The school-house came to life. "The drinking fountains were down very low for children and the blackboards were low," remembered Brian Dunne, Ted's college roommate from Caltech who soon joined the schoolhouse gang. "The machine shop used to be the kindergarten and all the drawers were way down there next to the floor."[61]
Participants in the summer-long workshop ranged from well knowns such as Edward Teller, Hans Bethe, and Marshall Rosenbluth to people like Manhattan Project nuclear chemist Bob Duffield, who had played a supporting role in the development of the atomic bomb. "Plutonium—it's warm, it's decaying all the time," explains Dunne. "They made this tiny piece of it, and it was so valuable they didn't dare send it by airplane to Los Alamos. They didn't even dare send it by train. They looked around for the most reliable way to get it there. And they chose Bob Duffield to haul it there in his old Oldsmobile." When General Atomic decided to send a prototype reactor to the second Geneva conference on peaceful uses of atomic energy in September 1958, it was Bob Duffield who got it there in working order and on time.
By 1956, the first micrograms of plutonium metal that had been produced in Chicago in November 1943 had grown into an industry whose scale was known to people like de Hoffmann but still largely hidden from public view. Enormous, industrial-scale operations such as Hanford in Washington State and Oak Ridge in Tennessee, built during the Manhattan Project, had expanded their production after the war, supplying the growing stockpile of U.S. weapons and a growing number of nuclear tests. The launch of the Nautilus in 1955 led the way to a fleet of nuclear submarines, and nuclear-powered aircraft, nuclear-powered surface ships, and nuclear-powered space vehicles were expected to be next. Amounts, costs, and production capacities of nuclear material were still strictly classified, leading to a vast invisible economy governed by the AEC. It was evident to General Dynamics, and others, that nuclear power stations would be the way to connect this hidden economy to the visible economy, with what promised to be lucrative results.
"We all knew even in 1937 that the world would soon run out of coal and oil," says Freeman, who, with many of his colleagues, expected a world dominated by nuclear power long before the century was out.[62] Freddy's invitation to La Jolla was a chance to repeat some of the technical challenges of Los Alamos, without the bomb project's moral qualms. "It was a marvelous summer," says Freeman, who lived in an apartment at the foot of Nautilus Street, a block from the legendary surfing beach at Windansea. "We had all of these people lecturing in the mornings and then having brainstorming sessions in the afternoons. I've never been involved in anything that worked so well. Freddy was the conductor of the orchestra. He never seemed to be harassed and he never seemed to be exerting authority, but somehow he made everything happen. He was always there when you needed him." The first order of business was to decide what kinds of reactors the group should design. It was Edward Teller, according to Ted, who stood up and said: "What the world needs is a safe reactor." Not only idiot-proof, but Ph.D.-proof. Inherent safety "must be guaranteed by the laws of nature and not merely by the details of its engineering," Freeman explained.
"There was a meeting at my house late one afternoon and into the night," recalls de Hoffmann. "We decided to decide what nuclear product was needed. We felt an ultra-safe research reactor was a finite enough project, that we could tackle this head-on and bring it about. Two of the younger members of the group, Freeman Dyson and Ted Taylor, were so inspired that, that night, they invented the uranium-zirconium hydride reactor."[63] The patent was granted to Freeman Dyson, Ted Taylor, and Andrew Mac-Reynolds, whose rights were sold, according to custom, to General Atomic for one dollar each. This was the best three dollars that General Atomic ever spent. The reactor became known as TRIGA: Training, Research, Isotopes, General Atomic. Some sixty-five TRIGAs have been installed on five continents, making it the best-selling reactor in the world. Producing everything from short-lived isotopes for use in hospitals to pulses as high as 2,000 megawatts for scientific research, TRIGA is the only nuclear reactor design that has consistently turned a profit for forty years.
General Atomic from the air, looking north, 1964.
Most nuclear reactors are governed by control rods of neutron-absorbing material inserted into the chain-reacting fissile core. Control rods make the difference between a critical mass that forms a reactor and a critical mass that forms a fizzling atomic bomb. "The result of suddenly pulling out the control rods," Freeman explains, "would in most cases be a catastrophic accident, including as one of its minor consequences the death of the idiot who pulled the rods."[64] Such an accident would be similar to what did happen at Los Alamos when a neutron-reflecting brick slipped from Henry Daghlian's hand, or what might have happened if the two parts of the super-critical Dragon had become jammed. Reactors have elaborate safety mechanisms to ensure that the control rods cannot be suddenly removed. This was not enough for Teller, who, as Freeman relates, decided that they needed to design a reactor that would be "safe even in the hands of an idiot clever enough to bypass the entire control system and blow out the control rods with dynamite."[65] Teller pushed for the safe reactor with the same intensity he had pushed for the hydrogen bomb. "Some of his ideas were brilliant, some were practical, and a few were brilliant and practical, Freeman says. "His intuition and my mathematics fitted together in the design of the safe reactor just as Dick Feynman's intuition and my mathematics had fitted together in the understanding of the electron."[66]
To make TRIGA inherently safe required a prompt negative temperature coefficient, meaning that as soon as the reactor core starts heating up, the rate of fission immediately drops. The key physical principle is the warm neutron effect: neutrons are less likely to produce fission as their temperature goes up. Conventional reactors achieve a negative temperature coefficient by surrounding the fuel elements with a moderator such as water that raises the neutron temperature as it heats lip. But if the control rods are removed suddenly, this external thermal moderation may not have time to take effect before the reactor core overheats and melts. If an effective moderator, such as hydrogen, could be incorporated within the fuel, the rise in neutron temperature would be prompt. TRIGA's inventors theorized that zirconium hydride would do the job. Hydrogen atoms are bound within a tetrahedral lattice of zirconium—which has one of the lowest neutron capture cross sections of any structural material—so that the evenly spaced quantum energy levels of the bound hydrogen maximize the warm neutron effect. Massoud Simnad, an Iranian metallurgist, soon developed an alloy of uranium hydride and zirconium hydride that worked as the theoreticians hoped. Some of TRIGA's prototype fuel elements have remained in operation for more than forty years.
As warm-neutron theory was translated into a working reactor, the foundations of Project Orion began to form. Just as at Los Alamos, the barriers between theoreticians and engineers were lowered and everything moved faster as a result. "I am amusing myself with uranium reactors and I find it absorbingly interesting to think about them," Freeman wrote to his parents in August of 1956. "Probably this summer is a turning-point in my life. I find the atomic energy business not only congenial, but also find I am good at it. My real talent is perhaps not so much in pure science as in the practical development of it. Just as Papa would never make music to himself in an ivory tower but always in the context of a particular group of people who would play it."[67] It was Stanley Koutz, Peter Fortescue, Brian Dunne, Robert Duffield, Ralph Stahl, and other experimentalists, technicians, and engineers who translated the theory of warm neutrons into a working reactor in under two years. "Freeman's warm-neutron paper was like the first draft of what you'd put on a patent application," says Dunne. "He gave guesses as to the total amount of U-238, U-235, zirconium, and hydrogen. It was a description of a workable reactor. I was struggling around trying to find one, and there it was, and it was clear."
The first prototype TRIGA was operational in May of 1958. By September, when TRIGA was exhibited in Geneva, orders were pouring in. "TRIGA was one of the grandest exhibits in the show—everyone wanted to see the blue light," says Brian Dunne. "They sold those things like hotcakes. Without TRIGA on the rails and selling briskly none of these other things would have been as easy." TRIGA gave General Atomic credibility in high places and Project Orion was next. The sales pitch to the board of General Dynamics was simple. "Here's the guy who invented TRIGA, and now he's really got this big, fantastic idea," says Ed Creutz.
In June of 1959, de Hoffmann brought in Niels Bohr, who had tried to engage Churchill, Roosevelt, and Stalin in a joint dialogue on atomic weapons and had initiated the 1955 Geneva conference on peaceful uses of atomic energy, to dedicate the new lab at Torrey Pines. The ceremony was followed by a demonstration putting the reactor's inherent safety to the test. "Niels Bohr pressed the switch and a muffled hiss was heard from the sudden release of compressed air that was used to pull the control rods at high speed out of the TRIGA core," Freeman reported. "The pointer on the large dial, which was graduated to show the power output of the TRIGA in megawatts, swung over instantaneously to 1,500 megawatts and then quickly subsided to half a megawatt. After the ceremony we went and saw it sitting quietly at the bottom of its pool of cooling water. Here it was. It was hard to believe. How could one believe that nature would pay attention to all the theoretical arguments and calculations that we had fought over in the schoolhouse three years earlier? But here was the proof. Warm neutrons really worked."[68]
Bohr, who "loved technical toys, just the opposite of Oppenheimer," according to Freeman, wanted to know what Ted and Freeman were up to next. "Being a Danish citizen and having no need to know, we couldn't tell him any of the details about the project," says Ted. "But on his own, apparently, in the course of a few hours he decided that it made sense." Late that night, over one of the glass tables beside the pool at the Hotel Del Charro, Bohr told Ted and Marshall Rosenbluth that he "had been looking for some really dramatic effort conceived in the United States that we could then go to the Soviets with and say, Let's do this together.'" Bohr continued to advocate an international Orion program until his death in 1962, sending Freddy de Hoffmann, among others, "a strong letter on that subject" and inspiring Ted with a hope "that the flag that would fly at every place Orion took people to would be the U.N. flag."[69]
On July 3, before Bohr left La Jolla, he joined Freeman for an evening picnic at La Jolla Shores. "For about half an hour Bohr talked to me alone as we walked up and down the beach," Freeman reported. "He at once understood and was enthusiastic about our space-ship. He thinks of it as something with which one may once again try to make a reasonable bargain with Russia. It was a tantalizing experience, as his voice is anyway almost too low to hear, and each time a wave broke his wisdom was irreparably lost."[70]