Mark 36 nuclear bomb

A Mark 36 casing is on display in the Cold War Gallery at the National Museum of the United States Air Force in Dayton, Ohio.

There were two major variants, conventional ("dirty") weapon designated the Y1 and a low fission fraction "clean" Y2 version.

[3] The clean variant used an inert fusion stage tamper-pusher assembly (see Teller-Ulam Design) such as lead or tungsten.

The "dirty" variant used a depleted uranium or U-238 tamper-pusher which would undergo fission during the second stage fusion burn, doubling the weapon yield.

Chuck Hansen wrote in Swords of Armageddon (1995) that Mark 36 nuclear bomb was produced in two yield versions, clean and dirty.