Stewart Bloom, 86, another CCNY trainee, recalls that Koval lacked a New York accent. "I always thought he was straight out of Iowa," says Bloom, a Chicago native. But in the urgency of war, Bloom says, he gave it little thought until nearly a decade after the war ended, when FBI agents showed up at the Brookhaven National Laboratory on Long Island, where he was then working, to ask about his former colleague.
The ASTP proved short-lived. Toward the end of 1943, just a few months after Koval enrolled, the war was tipping in favor of the Allies and the military was demanding ever more combat troops for a final push to victory. In early 1944, the program was dissolved and most of the participants were sent to the infantry.
Not Koval. He, along with Kramish and about a dozen others from CCNY, was selected for something called the Special Engineer Detachment (SED). It was part of the Manhattan Project, the covert enterprise that organized the talents of U.S., British and Canadian scientists at facilities across the United States for the purpose of designing and building an atomic bomb.
By the time Koval joined the SED in mid-1944, Manhattan Project scientists were pursuing two very different bombs. One was based on a known and relatively simple technology that required a rare, enriched form of uranium. (Indeed, it was in such short supply that its first "test" was in the bomb that destroyed Hiroshima.) The other bomb would use plutonium—an element that had not been isolated until 1941. The Oak Ridge laboratories were central to the development of both types of bombs.
Koval was assigned to Oak Ridge.
There, Koval's good fortune seemed only to build on itself, almost like a nuclear reaction: he was made a "health physics officer," charged with monitoring radiation levels throughout the sprawling facility. That, according to FBI files, gave him top-secret clearance. "He was one of the very few people who had access to the entire program," says Kramish, who worked in a different Oak Ridge lab. Still, the two saw each other frequently. In August 1944, Kramish was transferred to Philadelphia (where he was injured in a lab accident that killed two co-workers), but he returned to Oak Ridge before being assigned to Los Alamos, New Mexico.
"These things could not have been planned by the Soviets or anyone," writes nuclear historian Robert S. Norris in "George Koval, Manhattan Project Spy," a paper to be presented at a conference in Washington this month and published in the Journal of Cold War Studies. "Rather, it was just a lucky hit for the GRU."
Based on experiments conducted at Oak Ridge and elsewhere, reactors that could produce enough plutonium for a bomb were commissioned in Hanford, Washington. Meanwhile, scientists discovered that reactor-produced plutonium was too unstable for the bomb design they had in mind; the material would fizzle out. They had to come up with an "initiator" that would help the plutonium achieve the necessary chain reaction. For that initiator, they chose a form of another rare element, polonium—which was also produced at Hanford and Oak Ridge.
According to Lota, Koval was charged with keeping track of Oak Ridge's polonium. Through a Soviet contact known by the code name Clyde, Koval transmitted production information about it to Moscow via couriers, coded cables and the diplomatic pouch from the Soviet Embassy in Washington. One key fact he passed along was that Oak Ridge's polonium was being sent to Manhattan Project labs in Los Alamos—where Klaus Fuchs happened to be working as a Soviet agent.
"Fuchs passed the Soviets really detailed information on the design of the bombs," says David Holloway, a professor of history and political science at Stanford University and a leading authority on the atomic arms race. But Koval, he adds, knew that the polonium coming out of Oak Ridge "played some role in the development of the bomb"—knowledge that helped the Soviets connect the dots between Oak Ridge and Los Alamos.