<P> In the years immediately after the Second World War, the United States had a monopoly on specific knowledge of and raw materials for nuclear weaponry . American leaders hoped that their exclusive ownership of nuclear weapons would be enough to draw concessions from the Soviet Union but this proved ineffective . </P> <P> Just six months after the UN General Assembly, the United States conducted its first post-war nuclear tests . This was called Operation Crossroads . The purpose of this operation was to test the effectiveness of nuclear explosions on ships . These tests were performed at Bikini Atoll in the Pacific on 95 ships, including German and Japanese ships that were captured during World War II . One plutonium implosion - type bomb was detonated over the fleet, while the other one was detonated underwater . </P> <P> Behind the scenes, the Soviet government was working on building its own atomic weapons . During the war, Soviet efforts had been limited by a lack of uranium but new supplies in Eastern Europe were found and provided a steady supply while the Soviets developed a domestic source . While American experts had predicted that the Soviet Union would not have nuclear weapons until the mid-1950s, the first Soviet bomb was detonated on August 29, 1949, shocking the entire world . The bomb, named "First Lightning" by the West, was more or less a copy of "Fat Man", one of the bombs the United States had dropped on Japan in 1945 . </P> <P> Both governments spent massive amounts to increase the quality and quantity of their nuclear arsenals . Both nations quickly began the development of a hydrogen bomb and the United States detonated the first hydrogen bomb on November 1, 1952, on Enewetak, an atoll in the Pacific Ocean . Code - named "Ivy Mike", the project was led by Edward Teller, a Hungarian - American nuclear physicist . It created a cloud 100 miles wide and 25 miles high, killing all life on the surrounding islands . Again, the Soviets surprised the world by exploding a deployable thermonuclear device in August 1953 although it was not a true multi-stage hydrogen bomb . However, it was small enough to be dropped from an airplane, making it ready for use . The development of these two Soviet bombs was greatly aided by the Russian spies Harry Gold and Klaus Fuchs . </P>

When did the ussr became a nuclear power