Nuclear testing at Bikini Atoll
The nuclear testing at Bikini Atoll program was a series of 23 nuclear devices detonated by the United States between 1946 and 1958 at seven test sites on the reef itself, on the sea, in the air and underwater. The test weapons produced a combined fission yield of 42.2 Mt of explosive power.
The United States was engaged in a Cold War Nuclear arms race with the Soviet Union to build bigger and better bombs from 1946 until 1992. The first series of tests over Bikini Atoll in July 1946 was code named Operation Crossroads. The first test was dropped from an aircraft and detonated 520 feet (158 m) above the target fleet. The second, Baker, was suspending under a barge. It produced a large Wilson cloud and contaminated all of target ships. Chemist Glenn T. Seaborg, the longest-serving chairman of the Atomic Energy Commission, called the second test "the world's first nuclear disaster."
The second series of tests in 1954 was codenamed Operation Castle. The first detonation, Castle Bravo, was a new design utilizing a dry fuel thermonuclear hydrogen bomb. It was detonated at dawn on March 1, 1954. Scientists miscalculated and the 15 megaton nuclear explosion far exceeded the expected yield of 4 to 8 megatons (6Mt predicted), and was about 1,000 times more powerful than each of the atomic bombs dropped on Hiroshima and Nagasaki during World War II. The scientists and military authorities were shocked by the size of the explosion and many of the instruments they had put in place to evaluate the effectiveness of the device were destroyed.
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