Mark 11 nuclear bomb

It used a fixed large target assembly of highly enriched uranium (HEU), a gun-like barrel, and a powder charge and uranium bullet or projectile fired up the barrel into the target.

A total of 40 were produced, replacing but not expanding the quantity of Mark 8 bombs.

A major difference over the MK-8 was that the MK-91 had an electric operated actuator as a safety device that would rotate a spline ring to prevent the projectile from being fired into the target rings.

Upon release from the delivery aircraft detonation would occur after the black powder fuzes burned 90-110 seconds.

A "PHOEBE" polonium neutron initiator increased the nuclear detonation efficiency.