Kyshtym disaster

Kurchatov received more than 30.000 pages of secret documents from the Americans.

An excerpt from the article 42 facts about Kyshtym disaster

The Soviets received plans for the construction of a nuclear bomb, as well as information about the materials needed to make the bomb. Based on the plans they received, they learned that they needed nuclear reactors, uranium, and plutonium, but had none of the above.