Thin Man (nuclear bomb) Thin Man (nuclear bomb) "Thin Man" was the code name for a proposed plutonium gun-type nuclear bomb using plutonium-239 which the United States was developing during the Manhattan Project. They aborted its development when they discovered that the spontaneous fission rate of their nuclear reactor-bred plutonium was too high for use in a gun-type design, due to the high concentration of the isotope plutonium-240. In 1942, prior to the Army taking over wartime atomic research, Robert Oppenheimer held conferences in Chicago in June and Berkeley, California, in July at which various engineers and physicists discussed nuclear bomb design issues. A
B90 nuclear bomb B90 nuclear bomb The B90 was an American thermonuclear bomb designed in the mid-to-late 1980s and cancelled prior to introduction into military service due to the end of the Cold War making further nuclear weapon development unnecessary. The B90 design was intended for use as a naval aircraft weapon, for use as a nuclear depth bomb and as a land attack strike bomb. It was intended to replace the B57 nuclear bomb used by the Navy. The B90 bomb design entered Phase 3 development engineering and was assigned its numerical designation in June 1988. The B90 was 13.3 inches in