Castle Bravo Nuclear Test

Castle Bravo was the first in a series of high-yield thermonuclear weapon design tests conducted by the United States at Bikini Atoll, Marshall Islands, as part of Operation Castle. Detonated on March 1, 1954, the device was the most powerful nuclear device detonated by the United States and the first lithium deuteride-fueled thermonuclear weapon ever tested using the Teller-Ulam design. Castle Bravo's yield was 15 megatonnes of TNT (63 PJ), 2.5 times the predicted 6 megatonnes of TNT (25 PJ), due to unforeseen additional reactions involving lithium-7, which led to the unexpected radioactive contamination of areas to the east of Bikini Atoll. At the time, it was the most powerful artificial explosion in history. Fallout, the heaviest of which was in the form of pulverized surface coral from the detonation, fell on residents of Rongelap and Utirik atolls, while the more particulate and gaseous fallout spread around the world.