Chairman of the Joint Chiefs of Staff Fleet Admiral William D. Leahy military Joint Chiefs of Staff Nagasaki Fat Man atomic bombs
By 30 June 1946, there were components for nine atomic bombs in the US arsenal, all Fat Man devices identical to the one used in the bombing of Nagasaki. The nuclear weapons were handmade devices, and a great deal of work remained to improve their ease of assembly, safety, reliability and storage before they were ready for production. There were also many improvements to their performance that had been suggested or recommended, but that had not been possible under the pressure of wartime development. The Chairman of the Joint Chiefs of Staff, Fleet Admiral William D. Leahy, decried the use of the atomic bombs as adopting "an ethical standard common to the barbarians of the Dark Ages", but in October 1947 he reported a military requirement for 400 bombs.
