Castle Bravo Nuclear Test

Castle Bravo was the code name given to the first U.S. test of a so-called dry fuel thermonuclear device, detonated on March 1, 1954 at Bikini Atoll, Marshall Islands, by the United States, as the first test of Operation Castle (a longer series of tests of various devices). Unexpected fallout from the detonation—intended to be a secret test—poisoned the crew of Daigo Fukuryū Maru (“Lucky Dragon No. 5“), a Japanese fishing boat, and created international concern about atmospheric thermonuclear testing. ht