History professor Brian Balogh wrote a readable, academic 1991 book (most obscure in Australia) about nuclear debate, covering the three decades to 1975. In 1956, he writes, based on National Security Council papers (which I now wish I’d sighted):
…the OCB [Operations Coordinating Board] warned that “there are signs that the early emotional over-optimism on peaceful uses may turn into a corresponding emotional disillusionment.” At the same time, the OCB stated, “the Soviet Union has emerged as a challenger to U.S. leadership in Atoms-for-Peace programs.” According to the OCB, the Soviets had benefited by suddenly unveiling their power development program after years of secrecy and by setting specific targets – calling for 2.5 million kilowatts of nuclear power in their five-year plan.Balogh, Brian. 1991. Chain Reaction: Expert Debate and Public Participation in American Commercial Nuclear Power, 1945-1975. Cambridge University Press, United Kingdom, p. 104.
“Unveiling”? Igor Kurchatov had addressed the 1956 National Congress with his grandiose notions for the development of Soviet nuclear power, but none of the mooted 2.5 GWe had then even been proposed for approval. The Soviets would take years to launch much more modest build programs. Surely U.S. intelligence could winnow out the truth from the Soviet posturing? Apparently not.