The Mark-12 nuclear bomb was a lightweight nuclear bomb designed and manufactured by the United States which was built starting in 1954 and which saw service from then until 1962.
The Mark-12 was notable for being significantly smaller in both size and weight compared to prior implosion-type nuclear weapons. For example, the overall diameter was only 22inches, compared to the immediately prior Mark-7 which had a 30inches diameter, and the volume of the implosion assembly was only 40% the size of the Mark-7's.
There was a planned W-12 warhead variant which would have been used with the RIM-8 Talos missile, but it was cancelled prior to introduction into service.
The complete Mark-12 bomb was 22inches in diameter, 155inches long, and weighed 1100to. It had a yield of 12ktTNT14ktTNT.
The Mark-12 has been speculated to have been the first deployed nuclear weapon to have used beryllium as a reflector-tamper inside the implosion assembly (see nuclear weapon design). It is believed to have used a spherical implosion assembly, levitated pit, and 92-point detonation.
Though the weapon went out of service in 1962, it resurfaced in a fictional role in Tom Clancy's 1991 book The Sum of All Fears and the 2002 film, where the plot included an Israeli copy of the Mark-12 being lost by accident in 1973 during the Yom Kippur War in southern Syria near the Golan Heights, and then recovered by a terrorist organization.[1]