The picture below shows the Shrimp device , detonated on March 1 , 1954 at Bikini , as the Castle Bravo test . Its 15-megaton explosion was the largest ever by the United States . The silhouette of a man is shown for scale . The device is supported from below , at the ends . The pipes going into the shot cab ceiling , which appear to be supports , are actually diagnostic light pipes . The eight pipes at the right end ( 1 ) sent information about the detonation of the primary . Two in the middle ( 2 ) marked the time when x-radiation from the primary reached the radiation channel around the secondary . The last two pipes ( 3 ) noted the time radiation reached the far end of the radiation channel , the difference between ( 2 ) and ( 3 ) being the radiation transit time for the channel
Castle Bravo
Castle Bravo
Nuclear weapon design