The elaborate refrigeration plant necessary to keep its fusion fuel in a liquid state meant that the " Ivy Mike " device was too heavy and too complex to be of practical use . The first '' deployable '' Teller – Ulam weapon in the U.S. would not be developed until 1954 , when the liquid deuterium fuel of the " Ivy Mike " device would be replaced with a dry fuel of lithium deuteride and tested in the " Castle Bravo " shot ( the device was code-named the '' Shrimp '' ) . The dry lithium mixture performed much better than it was expected to , and the " Castle Bravo " device that was detonated in 1954 had a yield two and a half times greater than expected ( at 15 Mt , it was also the most powerful bomb ever detonated by the United States ) . Because much of the yield came from the final fission stage of its uranium 238 tamper , it generated much nuclear fallout , which caused one of the worst nuclear accidents in U.S. history when unforeseen weather patterns blew it over populated areas of the atoll and Japanese fishermen on board the '' Daigo Fukuryu Maru ''
Castle Bravo
Castle Bravo
History of the Teller–Ulam design