5 Nuclear Test Failures Caught on Tape

Castle Bravo was the first of several tests of a brand-new series of high-yield thermonuclear weapons conducted by the US military in the Marshall Islands under Operation Castle. The detonation was the first atmospheric test of a nuke fueled by lithium-deuteride. It was expected to yield a 6 megaton blast, but nuclear engineers were astonished by its ultimate power. On March 1, 1954, the Castle Bravo detonation produced a 15 megaton yield. In terms of energy released, it was about 1,000 times more potent than the Hiroshima and Nagasaki bombs. The incident became the most powerful nuclear explosion that the United States has ever detonated. The miscalculation occurred because engineers only considered the lithium-6 isotope to be reactive. This isotope accounted for 40% of the lithium content. The remaining 60% was lithium-7 isotope, which produced a larger neutron flux than expected and contributed to the detonation’s increased yield.