Kinglet (nuclear primary)

Kinglet was a boosted fission primary used in several American thermonuclear weapons.

The W55 warhead for the UUM-44 SUBROC anti-submarine missile and the W58 warhead for Polaris A-3 were designed to use Kinglet, while the W47 warhead for Polaris A-1/A-2 were retrofitted with Kinglet to overcome the technical issues with the Robin primary the W47 was initially deployed with. Allegedly, only the W47Y2 was converted to the Mod 3 design using Kinglet.

Design
The Kinglet device was approximately 11.2 - 11.57 inch in diameter, 11.5 - 12.2 inch in length and weighed approximately 58 - 63 lb.

The device was of the two-point design. Two-point devices only require two detonators to fire the whole device, compared to earlier nuclear weapons that required tens of detonators.

Characteristics of the warheads that used Kinglet are: