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
Timeline of the nuclear program of Iran "no evidence" that Iran is attempting to build an atomic bomb. November 13, 2003: The Bush administration claims that the IAEA conclusion of "no evidence" is "impossible to believe." December 18, 2003: As agreed in the Paris Agreement, Iran voluntarily signs and implements the Additional Protocol to the Nuclear Non-Proliferation Treaty Though the Protocol was not binding on Iran until ratified, Iran voluntarily agrees to permit expanded and more intensive IAEA inspections pursuant to the Protocol, which fail to turn up a nuclear weapons program in Iran. Iran ends the voluntary implementation of Additional Protocol after two years of inspections,