of our Institute of Optics, Chekhmataev, forbade the study of rare earths on the grounds that they occur only rarely in nature and thus could present no practical interest. Unfortunately, Chekhmataev, in his administrative zeal, was not alone. It turned out that, as if nature had deliberately planned it that way, creating an atomic industry called for profound knowledge of the physical and chemical properties of precisely the rare earths, f Luckily for us… Khlopin at the Academy of Sciences Radium Institute, despite all the prohibitions, continued working on rare earths. When a speedy solution of certain complex chemical problems of these elements was called for [i.e., uranium metallurgy], it was none other than Khlopin who rendered invaluable service. Had he… not shown the stubbornness with which a scientist will pursue his favorite “irrelevant” research, it would undoubtedly have taken longer to create our atomic bomb.
On the other hand, Frish observes, “the ability to carry out slated assignments quickly and as ordered, to throw our resources at the ‘bottlenecks’ and to close gaps as they arise” — abilities Frish attributes to the Soviet system of centralized planning — served them in good stead in their atomic enterprise. Nor did skeptical Americans like Groves take into account “the experience we had acquired during the war in the mounting of contemporary armaments production and the advances we had made in our precision-instruments industry as a result of captured German technology.”
The implication of Kurchatov and Panasyuk's 1943 proposal was that they were describing an original invention, but one month earlier, in June 1943, a small group of physicists at the University of Chicago Metallurgical Laboratory — the Met Lab — had begun designing a graphite-natural uranium reactor that was intended for use at Hanford testing the purity of the fuel elements destined for the big production reactors being built there. The Hanford 305 test reactor (so called because it was destined for building number 305 at Hanford) was the fourth nuclear reactor built in the United States, completed at Hanford in March 1944 and operated beginning in April. The Soviet F-l reactor as it was ultimately built shared many of the 305 reactor's significant physical parameters. Physicist Arnold Kramish, then an analyst for the Rand Corporation, noticed the parallels when the Soviet Union declassified details of the F-l design in 1955; in a Rand study he compared them in a table:
The two reactors differed slightly in their control-rod arrangements. The Soviet F-l design had three control rods — two for emergency scrams, one for adjusting reactivity — that descended vertically into the reactor. The American 305 had three horizontal control rods, Kramish notes, but three vertical holes as well. “A single boron- steel safety rod was suspended above the reactor. There were two other vertical holes, to accommodate a smaller metal safety rod, which could shoot small boron-steel pellets downward in an emergency.” The decision to forgo horizontal control rods in the F-l design appears to have followed from the difference in siting; the 305 was built above ground, but F-l was assembled in a pit with only about a meter of clearance around the reactor — not enough room to maneuver control rods horizontally. Both reactors were air-cooled. Both were designed to test the purity of graphite and uranium for the industrial-scale production reactors they supported. To that purpose, both reactors were built with channels bored through them into which samples of materials could be introduced. Both used internal and external boron ion chambers to measure activity from which their power was computed. Both used an unusual measurement technique involving computed reactivity to determine the purity of the materials being tested.
“The first Soviet reactor,” Kramish concludes, “was practically a carbon copy of the American 305 reactor built at Hanford… The similarity of construction is interesting. Is it coincidental, or were details on the 305 reactor obtained through espionage?” In the opinion of reactor experts, coincidence in so many particulars is not even remotely possible. Pioneer reactor physicist Alvin Weinberg points out that lattice spacing, at least, is determined by physical constants that Soviet scientists could have calculated as well as American — as indeed they did for F-l, since it was Kurchatov's practice to require his staff to work out the science and engineering independently of his espionage information in order to confirm its authenticity and to build a base of knowledge for further Soviet development. But reactor technology was still in its infancy in 1946 and there was no common body of technical literature available to consult; coincident identity among so many major design variables is unlikely. “To come up with the same design blind?” questions physicist Charles Till, a reactor inventor and designer and in 1995 the associate director of Argonne National Laboratory. “I wouldn't put any money on it, and I'm a betting man.”
If the F-l reactor design was based on espionage, who was the spy? Alan Nunn May could have had access to 305 details, although he arrived on the scene several months after Kurchatov and Panasyuk began planning F-l (not a fatal exception: plans for the reactor could have changed to reflect new information, as plans for the bomb did when Kurchatov learned through espionage of the virtues of plutonium). Or someone else at the Met Lab could have passed the plans — several other Met Lab scientists were observed during the war in contact with known Soviet agents, though they escaped prosecution. Whoever passed the information made a careful selection among possible designs, bypassing CP-1 and the Argonne heavy-water reactor for a system that was practical given Soviet uranium and graphite supplies and that served the further purpose of testing materials for the big production reactor being developed for Chelyabinsk-40. Uranium loading was a significant difference between the two designs; the 60 percent larger Soviet loading is evidence of the difficulties the USSR had purifying uranium.
No one connected with the Soviet atomic-bomb program has ever acknowledged that espionage was the basis for the F-1 design.
Beria's hand is evident in the functional similarity between the 305 test reactor and F-1 — the fact that both machines were intended for materials testing. If the F-1 design was based on the 305, Kramish comments, then “rather than attempt an independent and improved materials testing reactor, the Soviets chose to copy a sure thing. This suggests at this stage of the Soviet program both a sense of urgency and a lack of technical self- confidence.” V. S. Fursov, a physicist who worked on F-1, admits that “there was some reason to consider the proposed construction… as something other than a completely guaranteed undertaking.” Even if Kurchatov had been confident of the purity of the materials available to him and of the accuracy of the physical measurements his team had accomplished with limited resources, copying a sure thing was standard operating procedure in Soviet industrial espionage, as Harry Gold knew all too well.
Igor Kurchatov may have based F-1 on the 305 test reactor, but he and his colleagues still had to repeat the measurements, experiments and tests that the Met Lab reactor physicists had carried out. The Soviet scientists had to do so not only to check for disinformation. They also needed to learn the craft of reactor design and construction, which simply reproducing a copy could not teach them. Their resources were different as well — less pure and less dense graphite, less pure uranium metal — and dictated differences in design. “We paid serious attention to the choice of materials and the design of every detail of the reactor,” Pervukhin insists. “… We had to deliver; we couldn't afford to take the time to improve the design later.” In that serious attention lay the difference between Lavrenti Beria's uninformed approach to the “atomic problem” and the scientific approach Kurchatov followed. Beria wanted copies, as if nuclear reactors and atomic bombs were no more complicated than a jeep or a B-29; Kurchatov insisted on accumulating a working body of knowledge to guard against present failure while building a future. It was Kapitza's point, but Kapitza had been expendable. Kurchatov was not.
“On a plot of grass outside Kurchatov's office window,” Golovin remembers of the time when construction began on F-1, “two army tents were erected.” Soldiers began digging a pit under the canvas for the reactor while “I. S. Panasyuk began to stack graphite columns to measure the absorption and moderation of neutrons in graphite.” The pit was supposed to be dug ten meters deep (thirty-three feet), but at seven meters the workmen encountered groundwater and had to stop short; the reactor would project a little way out of the ground.
For a uranium metal and graphite reactor to operate at all, the uranium cross section for slow-neutron absorption had to be no more than 4–5 ? 10'–27 square centimeters. “The tests with the first batches of graphite,” recalls Panasyuk, “gave values of 50-500 ? 10–27 cm2.” The chemists who analyzed the various batches of graphite reported kinds and levels of impurities that failed to account for the unacceptably high cross sections that Panasyuk found. “Kurchatov advised us not to become desperate but to wait until the results of tests for all the batches of graphite [being processed] became available.” Kurchatov knew from espionage what he could not directly tell Panasyuk — that sufficiently purified graphite would work and therefore the chemical analyses must be wrong. With specific exceptions, cleared in advance, Kurchatov was required to keep the members of his team in the dark about the espionage information he received. “He was not authorized to tell them,” confirms Anatoli Yatzkov, “so he didn't.” Russian astrophysicist Roald Sagdeev, one of the younger generation of Soviet physicists, heard the stories:
