New Evidence of a Soviet Spy in the U.S. Nuclear Program

Two former nuclear scientists make the case that a spy took nuclear secrets to the Soviet Union.

A giant column of smoke rises more than 60,000 feet into the air, after the second atomic bomb ever used in warfare explodes over the Japanese port town of Nagasaki, on August 9, 1945.

In a new book, two former nuclear weapons scientists make the case that Soviet spies didn't just steal atomic secrets from the Manhattan Project in the 1940s—something historians have known for years—but say a previously unknown spy also helped the Soviets design their first hydrogen bomb. The Soviet Union detonated its first thermonuclear bomb in 1953, only a year after the first American H-bomb was tested, ending the period of nuclear supremacy the U.S. military enjoyed after World War II.

In The Nuclear Express: A Political History of the Bomb and Its Proliferation, published this month, Danny Stillman and Thomas Reed, two longtime veterans of the U.S. nuclear weapons program, do not provide the name of the spy they say took hydrogen bomb secrets out of the Los Alamos, N.M., weapons lab. But they do offer some of his biography, saying he was born in the United States, raised abroad, came under the sway of the Communist Party in the 1930s, and took a job at Los Alamos during World War II.

Stillman and Reed say in the book that they have refused to reveal the name of the suspected spy, who is now dead, because he "can neither defend his family name nor refute our arguments." They say his name doesn't really matter, anyway: "His fingerprints are what count."

Stillman, a physicist who worked at Los Alamos from 1965 until 2000, says he tried to make a case against the scientist in the 1990s, going to the FBI after he noticed the man's apparent wealth. The local Santa Fe office bungled the investigation, the authors say, and the inquiry was "botched beyond recognition." The FBI eventually became distracted by the modern-day spy scandal surrounding Wen Ho Lee, another scientist working at Los Alamos, and stopped pursuing the case, the authors say.

As the Cold War faded into memory, the authors say they began to get their first real confirmation that the Soviet H-bomb effort had help from someone inside the American nuclear program. In particular, they say Russian scientists told them at a meeting in the late 1990s that the Soviet bomb designer, Andrei Sakharov, had privately refused to take full credit for the hydrogen bomb. The Russians hinted that Sakharov knew he'd gotten a boost from someone in the American program.

Former Soviet weapons experts have also said they were given a copy of an early design drawing of a "radiation implosion," the technology used in hydrogen bombs, that appeared to have been sketched in the early 1950s by an American H-bomb designer. The document was apparently stolen or copied and found its way to the Soviets. Stillman and Reed say there is only one way this kind of information could have ended up in Soviet hands: a spy.

Most historians seem to be leery of Stillman's and Reed's conclusions, barring more hard evidence. But they say the notion of a Soviet spy inside the early American atomic program isn't so far-fetched. There is little doubt, in fact, that the Soviets' first nuclear weapon—a plutonium bomb like the one dropped on Nagasaki, Japan—was the result of espionage. "We know now that their first design was a carbon-copy of the 'Fat-Man,' " Robert Norris, a researcher at the Natural Resources Defense Council and the author of Racing for the Bomb: General Leslie Groves, the Manhattan Project's Indispensable Man, said in an interview earlier this year.

Nearly a dozen Soviet spies—including Julius and Ethel Rosenberg and Klaus Fuchs—were executed or imprisoned after World War II for passing atomic secrets to the Soviets, including information about the plutonium bomb and the early work on the hydrogen bomb. Last year, Vladimir Putin, then Russia's president, shocked American historians and government officials alike when he announced that an undetected spy, George Koval, had also penetrated the Manhattan Project.

Putin said Koval, an Iowa-born son of Russian Jewish immigrants, had provided the Soviets with information about American atomic production levels while working at nuclear facilities in Oak Ridge, Tenn., and Dayton, Ohio. Koval moved back to Russia in the 1950s and died in 2006. He was posthumously awarded the Hero of Russia medal.

Corrected on : Corrected on 01/07/09: An earlier version of this article misstated the year the Soviet Union tested its first thermonuclear bomb. The first Soviet test was in 1953, one year after the first U.S. test in 1952.