• • •
Glenn Seaborg arrived in Chicago to take up his assignment from Compton on Sunday, April 19, 1942. The blustery day was his thirtieth birthday. He understood the challenge ahead, for he and his colleagues had yet to produce a speck of element 94 detectable even by microscope. The work, as he put it wryly, involved “invisible materials being weighed with an invisible balance.” The scientists could determine if plutonium was present only by reading its trace radioactive signature; this was science performed not by observation but by deduction.
Compton named Seaborg’s group Section C-1 and gave it space on the fourth floor of the University of Chicago’s Herbert A. Jones Laboratory, where the aging benches, sinks, and fume hoods reminded Seaborg of the laboratories he had haunted in his undergraduate years. Now he was the man in charge, however, and his first task was to fill out his team. Taking a page from Ernest Lawrence’s recruitment handbook, he reached out to the best chemists he had known as classmates and fellow faculty members, and dangled before them the prospect of career-making jobs on a project that, alas, he was not at liberty to describe. “Unfortunately I cannot divulge to you the nature of the work but . . . you are in a fair position to guess,” he wrote a college friend whom he knew to be unhappy in an oil company job. “It is the most interesting problem upon which I have ever worked.”
It was a difficult sell. Seaborg had Lawrence’s verve and enthusiasm but not his reputation, and he was not always successful at persuading his quarries that his mysterious summons warranted their dropping everything and moving to Chicago for an indefinite period. Still, within five months, he had assembled a staff of twenty-five; within a year of his arrival, it would be fifty, and at its peak, one hundred.
Their primary goal was to bombard uranium to obtain sufficient plutonium for study. There were two methods to choose from: a cyclotron-generated neutron beam or a chain-reacting atomic pile. But the first produced minuscule quantities; at a production rate of 1 microgram of plutonium per week of uranium bombardment, Seaborg calculated it would take the cyclotron twenty thousand years to make a single kilogram of element 94. A chain-reacting pile would be more efficient but still existed only in theory, for Fermi’s most recent prototype had produced less than one neutron per fission—a definite fizzle. Even assuming that a chain reaction could be started and maintained, the task would remain of extracting the plutonium—concentrated at 250 parts per million, or a half pound per ton of uranium—from material so radioactive that the processing would have to be done from behind walls of dense concrete.
Luckily, Seaborg did not need a kilogram of plutonium just then, only a few micrograms. And for that, the cyclotron at Washington University in St. Louis, which Compton had built before moving to the University of Chicago, would do. Seaborg’s group commandeered the cyclotron to bombard uranium twenty-four hours a day. Over the next eighteen months, this indefatigable machine would produce two thousandths of a gram of plutonium, a quantity about the size of a grain of salt. Seaborg monitored the work with only a single break in his routine: a quick visit to Berkeley to collect Helen Griggs, his bride-to-be, followed by a hurried wedding in a dusty Nevada town called Pioche and a wedding night in a hotel room on the second floor of the rail depot. From there the married couple continued on to Chicago by train. Soon after their arrival, the first shipment of irradiated uranium arrived from St. Louis by truck: three hundred pounds of it packed in plywood crates shielded by lead bricks. Some of the boxes had broken open on the way, spilling hot uranium over the truck bed; Seaborg advised his assistants to wear rubber gloves to sweep up the detritus. Once they hauled the cargo upstairs to their lab, they let it cool for a week before beginning the tedious process of reduction, oxidation, precipitation, and extraction.
A breakthrough came on the morning of August 20. Seaborg’s microchemists used hydrofluoric acid to reduce a solution made from the bombardment products and watched a minuscule quantity of pinkish material precipitate out: this was pure plutonium-239. As Seaborg reported in his journal, it was the first time that plutonium—indeed, any synthetic element—had been seen by the naked eye. “I’m sure my feelings were akin to those of a new father,” he wrote. It had been twenty months since he and Joe Kennedy had identified element 94’s alpha signature in their microscopic sample. With Fermi’s chain-reacting pile still undergoing its difficult gestation, for all they knew this was the only plutonium that would be seen for months, or even years.
All that day and into the evening, Met Lab associates streamed into room 405 of the Jones Lab to peer through the microscope at the pink speck. A few weeks later, General Groves was ushered upstairs to view the plutonium sample for himself. He put his eye up to the microscope, where a researcher had set the sample on a glass plate with exquisite care.
“I don’t see anything,” he growled. “I’ll be interested when you can show me a few pounds of the stuff!”
• • •
Groves’s order to freeze the calutron design was honored only in the most general terms, and then only for the very first units to be shipped for installation at Oak Ridge. This was inevitable, for the separation process was so novel that no firm specifications could have been devised without continued experimentation by the Rad Lab, even after the start of construction of Y-12. The mass and purity of the U-235 collected from the calutrons varied widely depending on the pressure within the units, the strength and shape of the magnetic field, the voltage of the accelerating electrodes, and myriad other factors, all interrelating in ways not fully understood.
Lawrence originally calculated that two thousand calutron source-and-collector arrays—two thousand vacuum tanks, or about twenty racetracks—would yield 100 grams a day of U-235. By January, the calutron had been modified so that each one could be operated with pairs of sources and collectors. That would double their output or, to put it another way, reduce the requirement for 100 grams of daily production to only one thousand tanks. Having absorbed Lawrence’s confidence that further efficiencies eventually would be achieved, Groves reduced the specification for Y-12 to five hundred tanks, or five racetracks. The plant was built with sufficient room to install more tanks if production failed to continue ramping up. Groves set a punishing pace for construction, demanding that the first racetrack be running by July 1, 1943, and all five by the end of the year. These deadlines left no time for idle theorizing. The Rad Lab returned to the days of cut-and-try; any configuration that produced a stronger or sharper beam was incorporated into the standard, even if the experimenters could not figure out why it worked.
Every piece of equipment had to be machined to the most demanding specifications and designed for the heaviest duty. Gaskets had to survive extreme temperature changes and maintain their airtight seal over long periods of constant operation. Vacuum pumps, a constant source of frustration for the Rad Lab staff even when the machinery operated at its best, had to be scaled up to gargantuan dimensions so they could rapidly reestablish vacuums in tanks that would be regularly opened for cleaning but had to be promptly returned to service. The collectors were repeatedly redesigned in a never-ending effort to keep the deposits of U-235 and U-238 apart.
For the Rad Lab, the most familiar design elements were the magnets. After all, they had already erected the largest magnet in existence for the 184-inch cyclotron. But that did not mean designing the Y-12 magnets would be without its challenges, for all the racetrack magnets combined would be one hundred times larger.
This led to the first major procurement crisis of Groves’s tenure. The original magnet design called for using copper for the electromagnet coils and the massive transmission bus that carried electricity to the racetracks. But the entire national supply of copper had been requisitioned for other war needs, and not even Groves’s bullishness could overcome that cold fact. As an alternative, the designers settled on silver. That metal was also in short supply—except for the US Treasury Department’s monetary reserve, which was located in a vault at West Point. Gro
ves demanded access to the hoard and got his way. Some 14,700 tons of silver worth more than $300 million were procured from the depository on the understanding that every ounce would be returned after the war. The appropriation of the silver bullion underpinning the US dollar was kept absolutely secret, its milling into electrical cables and its transport watched over by armed military guards until the finished product arrived at Oak Ridge. Groves kept his promise: the precious metal was all returned to the Treasury, though the last of it was not transferred until 1968.
In General Groves, Lawrence encountered—possibly for the first time in his adult life—someone who was even more driven than himself. Ernest now found himself in the unaccustomed position of being regularly outflanked and outrun on decision making; often Groves would make a show of consulting with him, sometimes even visiting Berkeley as part of the charade, only to disclose at last that he had settled unilaterally the question supposedly under joint consideration. Thus a debate over which contractor to place in charge of operating Y-12 ended with the appointment of Tennessee Eastman Corporation, a Kodak subsidiary with which Groves finalized a deal while Lawrence was still pondering a list of candidates. Equipment manufacturers were appointed in the same mysterious manner while supposedly awaiting Lawrence’s approval. Instead, he would learn that the decision had been made and contracts signed, and that Groves was already on his way to Berkeley with representatives of the contractors—Westinghouse, General Electric, or the Allis-Chalmers Manufacturing Company—demanding a full Rad Lab briefing about the process and the equipment they were expected to manufacture and install in Tennessee a month or two hence.
Yet Groves was fully cognizant of Lawrence’s crucial role in the program. Without Ernest’s energy, his serene self-confidence, and his charismatic command over the scientists and engineers inventing the separation process, there would be no Y-12. Groves placed Lawrence within the same bubble of personal security he ordered for Oppenheimer and a few other indispensable Manhattan Project personnel, notifying him by letter of “certain special precautions” he was to take for his personal safety. Among these was an absolute ban on “flying in airplanes of any description,” except with Groves’s explicit consent. Lawrence was not to get behind the wheel of an automobile for any distance longer than a few miles, or travel “without suitable protection on any lonely road” or after dark. Instead, he was provided with an armed chauffeur at government expense.
Nowhere was the awe-inspiring scale of the Manhattan Project—in spending, in manpower, in physical size—as evident as at Y-12. The electromagnetic separation plant was the largest and most complicated installation in the valley. By the end of the war, Groves calculated, its construction, engineering, and electricity would cost more than a half billion dollars, making it the single most expensive component of the Manhattan Project. During a two-week period of construction, 128 carloads of electrical equipment arrived by rail. Deliveries of concrete blocks filled 63 railcars; lumber—38 million board feet—another 1,585 cars.
When Lawrence visited Y-12 in May 1943, less than three months after ground had been broken, the sight of the transformed valley left him spellbound. He had been primed to expect big things after inspecting the bustling Westinghouse, General Electric, and Tennessee Eastman factories turning out equipment for Y-12. But the Clinton Engineer Works, the official name of the Tennessee site, looked to be in a class of its own. Four immense two-story buildings were rising in various stages of construction. Cow paths had been transformed into paved thoroughfares, railroad tracks crisscrossed the valley floor, and electric lines snaked over the ridges and connected up to a vast switchyard hulking with transformers. “When you see the magnitude of that operation there,” he reported back to the Rad Lab staff, “it sobers you up and makes you realize that whether we want to or no, that we’ve got to make things go and come through . . . Just from the size of the thing, you can see that a thousand people would just be lost in this place.” Great achievements always inspired Lawrence to think bigger, and Oak Ridge was no exception. “We’ve got to make a definite attempt to just hire everybody in sight and somehow use them, because it’s going to be an awful job to get those racetracks into operation on schedule. We must do it.”
Groves was anxious to advance Y-12 from the experimental phase to industrial operation quickly, despite warnings from the Rad Lab that what its scientists did not know about electromagnetic separation still outweighed what they could say for certain. Other players expressed similar concerns. When an executive at Tennessee Eastman fretted that his firm might not be capable of the scientific research needed to build a U-235 plant, the executive recalled, Groves snapped that he already had “so many PhDs that he couldn’t keep track of them.” What he needed from Eastman was its industrial expertise.
Lawrence relocated one hundred of his Berkeley staff to Oak Ridge to tune the calutrons personally. His recruitment method, perfected for the MIT Rad Lab, held firm: “Would you like to go to Tennessee?” he’d ask a candidate. Anyone who responded with even a conditional assent was told, “Good. You leave the day after tomorrow.”
The Berkeley scientists arrived to find Y-12 mired in mud, chaos, and rock-bottom morale. With its bulldozer-graded streets and its rows of prefab houses, Oak Ridge looked like an “unfinished movie set,” recalled Seaborg. Everything was encrusted in dense Tennessee clay. Those who braved the Oak Ridge cafeteria invariably suffered an introductory bout of intestinal distress dubbed “Clinton fever.” The physical conditions were overlaid with military regimentation far beyond anything imposed at the Rad Lab, even after its absorption into the bomb project. Portions of Y-12 were partitioned off so that the scientists could not cross from one end of its vast floor to the other without stopping repeatedly to show their passes.
Things seemed to run smoothly only when Ernest was on hand. This was discouraging, since the demands on his attention elsewhere were multiplying. Still, he had only to make an appearance at Y-12 for all the issues of logistics and construction staging and equipment design that had piled up in his absence to evaporate. There, as at Berkeley, he convened a policy meeting every morning at eight, marched into the room to its most comfortable chair, and launched the proceedings with a breezy “What’s new?” He absorbed the details of every problem instinctively, formulated a solution or a path to the solution as he listened, and moved rapidly on to the next item. Lawrence’s visceral feel for the mechanics and capabilities of the calutrons matched the mysterious affinity he had always shown for the cyclotrons. “He felt it in his bones,” marveled Bill Parkins, the Cornell recruit.
Another malady suffered by the Berkeley transplants was severe culture shock. Primed to disdain the young women recruited from the Tennessee hollows to work as calutron operators—many of whom were most comfortable padding around the floor barefooted and conversing with one another in an impenetrable back-country drawl—the Berkeley PhDs could not get their minds around the thought that the success of Y-12 depended on these platoons of “essentially illiterate hillbillies,” as Kamen labeled them. “Mass spectrometers were still lab instruments of extreme fragility and erratic performance, which could be operated only by highly trained technicians. To assert that they could be built on the scale needed and operate more or less on a push-button basis was to invite invitations to don a straitjacket.”
Nor were the women themselves immune from culture shock. They were trained to perform a purely mechanistic job “watching meters and adjusting dials” from swivel chairs set before tall steel consoles marked only with numerals. They reported to work in vast factories that had appeared almost overnight—at least they seemed to be factories, but there was “no receiving dock and no loading dock,” Parkins reported. “Nothing went in or out, but everybody was very busy.” Women who inquired about their jobs were told “a cock-and-bull story about broadcasting radio signals that jammed the communications of our enemies” or, as one instructor told his training class, “I can only tell you that if our enemies beat us t
o it, God have mercy on us.”
Yet the Tennessee women outdid the Berkeley scientists in one crucial quality: patience. Once Y-12 was operational, their equanimity made them superb operators. Indeed, Colonel Nichols, exasperated by the scientists’ condescension toward his workforce, soon informed Lawrence that the women could outproduce the scientists and that he was prepared to prove it in a production race. Lawrence accepted, and lost. The reason, Nichols reckoned, was that the women were trained to follow without debate or explanation the instructions they were given, so they went ahead without distractions; the scientists, however, could not avoid investigating the cause of even the most minor fluctuation of their meters—and since they actually knew what every figure meant, they were constantly making trivial and unnecessary adjustments. As Nichols understood, once the plant entered the production phase, what was needed was unquestioning operation, not ceaseless tweaking.
Lawrence regarded Y-12 as his personal fiefdom (notwithstanding the eleven thousand Tennessee Eastman employees who made it run). On his frequent visits, he could be spotted chatting amiably with workers or engineers, sometimes in the company of less patient companions, such as Groves. One time he gave a lengthy tour to a tall, stoop-shouldered man with a lugubrious expression on his long face, whom Lawrence introduced with unusual deference as “Dr. Nicholas Baker.” This was the code name of Niels Bohr, whose gloom reflected his misgivings about the horrific weapon being brought forth by his own discoveries. Lawrence, of course, displayed no such doubts, which may only have deepened “Dr. Baker” ’s dismay.
Many issues raised at Lawrence’s briefings resulted from the decision to begin construction of Y-12 before the central technology was perfected. An alteration in calutron design that seemed trivial in Berkeley could set off an avalanche of costly and time-consuming changes downstream at Oak Ridge. New designs kept flowing out of Berkeley: by the end of the program, 71 different types of ion sources and 115 designs for the receivers and collectors had been prototyped and tested, with the results sent on to Groves. Some design changes arose from Lawrence’s own indefatigable quest for the next big technical advance. He implemented the doubling of the source-and-collector arrays in the calutrons without much fuss, but even before they were installed, he was pondering four arrays, and then eight, and then sixteen—each upgrade requiring new studies of beam interference and power consumption.
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