though Fermi's reactor had pioneered the technology.
Kurchatov and Panasyuk sat down at the F-l control panel late in the afternoon, Dubovsky remembers:
All radiation-measuring equipment was switched on. We checked the functioning of the control and protection systems. The emergency rods were pulled completely out of the reactor but not locked; from this position they could be dropped into the reactor in one second. Then Kurchatov personally began winching out the control rod. We were all very anxious, of course… Everyone was silent. The only sounds were the clicks of neutron counts from the loudspeakers and Kurchatov's brisk orders.
Kurchatov stopped the control rod with 280 centimeters (9 feet) still inserted into the reactor. The clicks of neutron counts and the flashes of red light from the gamma-ray counters multiplied. “Everybody got excited,” reports Panasyuk. Kurchatov watched the light on the galvanometer connected to the main neutron counter. “The beam did not move even after ten minutes had elapsed,” Panasyuk continues. “The frequency of the clicks and flashes increased and then steadied.” Kurchatov checked the graph of neutron intensity Dubovsky was plotting, declared that they had not yet achieved a self-sustaining chain reaction and immediately shut the reactor down.
They took a ten-minute break. When they were all back in their places, Kurchatov winched the control rod 10 centimeters (4 inches) farther than before. (“Ever since his Leningrad days,” reminisces Kurchatov's colleague V. A. Davidenko, “taking measurements, Igor Vasilievich would always start a stopwatch or flip a switch to his favorite countdown: ‘Ready?
Another ten-minute break. Panasyuk:
Kurchatov quickly removed the two emergency rods from the reactor. As the seconds passed, the graph showed an almost linear growth of reactor power. For the first time the sound turned into a roar. The indicator lamps no longer blinked but burned with a reddish-yellow light. Everyone watched Kurchatov with excitement while he studied the graph. After awhile he declared that although the effective multiplication ratio had reached 1, that did not yet prove that the reactor was functional. It was necessary to repeat everything from the beginning.
One final run-up. Kurchatov dropped the emergency rods and withdrew the control rod only 5 centimeters more. Panasyuk does not say they took a break. Out came the emergency rods:
In thirty minutes all the sound indicators were roaring, the light indicators glowing and the galvanometer beam from the boron trifluoride counter [inside the reactor] deflecting not in an even way, as in the previous series, but in an accelerating progression. The tension became extreme when the second boron trifluoride counter, which was located within the underground control room, began producing more frequent clicks than its background of two or three per minute — an increase which meant that neutrons from the reactor had penetrated the thick layers of earth and cement and reached the room…
Kurchatov pressed the button that dropped the emergency rods.
On December 26, they measured its neutron doubling time at 134 seconds. Within a few days, says Panasyuk, “this level of supercriticality no longer suited either the creators of the reactor or its increasing number of users.” More uranium had become available by then; Kurchatov decided to enlarge the uranium loading, adding several more layers to reduce the doubling time to twelve seconds.
F-l was their first concrete achievement and they were proud of it. They used it to test the purity of the uranium and graphite being prepared for Chelyabinsk-40: they pushed samples of the test material through a channel into the center of the reactor and measured the extent to which the test material affected F-l reactivity. They used the little reactor to determine the optimal grid spacing for the production reactor and to test its control and monitoring equipment. Most crucially, operating from a backup control room a kilometer away from the reactor building on weekends and over holidays, they ran the reactor remotely at one-thousand-kilowatt power levels to breed plutonium.
A few days after the start-up, Beria came to see what his scientists had wrought. They had shut the reactor down so that he could watch it come alive. With Beria in the underground control room, write Golovin and Smir-nov, “Igor Vasilievich put the winch in motion, lifting the control rod. The clicks increased and gradually transformed into a continuous roar. The light beam of the galvanometer ran off the scale. The people on hand shouted ‘It's going!’ meaning the chain reaction.” Beria had seen massed assemblies of Stalin's Organs fire racks of screaming Katyushas; here were only clicking counters and flashing lights. “And that's all?” he challenged Kurchatov. “And nothing else?” He wanted to see this famous machine for himself and asked to approach the reactor. “No,” Kurchatov told him. “You can't go down there now. It's dangerous to your health.” That made Beria more suspicious: where was the danger? “Beria began suspecting that Kurchatov was swindling him,” Golovin and Smirnov report.
Beria was habitually suspicious, of course; his rise to power in the criminal enterprise that was the Soviet Communist Party and his duties along the way demanded that he be. Anatoli Yatzkov says Beria questioned “the idea of nuclear weapons even when nuclear weapons work in the Soviet Union had achieved large scale.” His doubt may have arisen from his ignorance of science and from his intellectual and parvenu insecurities. If he suspected the scientists were swindling him, Kapitza's assault on his leadership can only have deepened his suspicions. But Beria even doubted the veracity of the information that his own espionage apparatus had collected, Yatzkov notes: “L. R. Kvasnikov says that once, when he was reporting to Beria on intelligence information, Beria threatened him, saying, ‘If it's disinformation I'll throw you all into the cellar.’ When the head of intelligence, P. M. Fitin, hinted that it was high time to reward agents for their accomplishments, Beria berated him that it was not yet clear if they deserved reward or punishment.”
Beria seems to have been incredulous that the United States would allow its most strategic military technology to be stolen so easily, that spies so perfectly positioned as Fuchs had been would simply walk in off the street and volunteer, that privileged citizens would willingly subvert their nation's commanding military advantage in the service not of fear or cold cash but of insubstantial ideals. The bribes and the medals that his subordinates kept throwing at their surprised, amused or indignant charges imply a need to mark these volunteers with some feculence Beria could recognize. (In England after the war, Fuchs accepted a gift of one hundred pounds from his Soviet contact because “security precautions had been tightened up after the exposures in Canada [as one of his interrogators paraphrases him] and he felt that in accepting this money he was more or less assuring his contact of his loyalty.”) And if scientists in England and the United States were such nai'fs, how could he trust his own?
Kurchatov and Alexandrov had their work cut out for them convincing Beria that the plutonium-production reactor should be different from the reactors the United States had built at Hanford. The Hanford production reactors were horizontal cylinders of graphite bored with several thousand horizontal channels into which aluminum-clad fuel elements could be loaded. When the fuel elements had been irradiated long enough to transmute some of their U238 into plutonium, they could be pushed through the reactor out the other end for plutonium separation. Military security was crucial to the Soviet project, however — Chelyabinsk was potentially within range of American B-29s — and in pursuit of that security the Chelyabinsk reactor would be sheltered underground, in a huge pit, like F-l. The pit, as well as the scientists’ first experience with F-l, argued for a vertical design. “Every day,” Pervukhin recalls, “there were heated arguments in the reactor section concerning the choice of design for the industrial reactor. After lengthy discussions, the vertical design was chosen. But the project for a horizontal graphite reactor was prepared as well, and only after considering all the arguments for and against did everyone agree on the advantages of the vertical design.” It is significant that those advantages primarily concerned security, a subject Beria understood.
In the meantime, the scientists were learning what it meant to work for Lavrenti Beria. “The successful startup [of F-l] brought confidence to all who worked on the problem,” says Pervukhin, “and showed them they
