The Soviet Union developed their first nuclear bombs only a few years after the United States , undoubtedly aided by espionage . The USSR entered the nuclear age in 1949 with their imitation of the American Fat Man plutonium implosion design . Although the Soviet Union was behind the U.S in the years following World War II in terms of nuclear development , they soon closed the gap . By 1953 , the U.S successfully tested the world 's first hydrogen bomb , Ivy Mike with a yield of about 10 MT. It was only two years later on August 12 , 1955 that the Soviet Union successfully tested their own hydrogen bomb , the RDS-6 ( known as Joe-4 in America ) . In addition , the development of stealth and fighter bombers by the USSR were heavily modeled on the American counterparts , the B-2 and B-47
Ivy Mike
Ivy Mike
Nuclear triad