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Mk 4

Mk 4
Aircraft bombUnited StatesImplosion fission
Mk 4
Photo: unknown author · Public domain · background removed
Yield · TNT equivalent1–31 kt

Key specs

Design
Implosion fission
Type
Aircraft bomb
Weight
4.9 t
Length
3.25 m
Diameter
1.52 m
In service
1949–1953
Number built
550

Overview

The first mass-produced American atomic bomb, a post-war refinement of Fat Man with interchangeable plutonium and uranium cores. Depending on the core, its yield ranged from 1 to 31 kt.

Effect radii: estimates

Calculated for 31 kt

Fireball, maximum radius
≈ 240 m
Initial radiation, 500 rem (5 Sv)
≈ 1.6 km
Blast 5 psi: most buildings collapse
≈ 2.2 km
Thermal: third-degree burns
≈ 2.7 km
Blast 1 psi: windows shatter
≈ 6.9 km

Estimated ground ranges for an air burst at the optimum height over flat, open ground, computed from the yield with standard scaling laws. These are not measurements: real effects depend on the height of burst, terrain, buildings and weather.

Formulas from: Glasstone & Dolan, The Effects of Nuclear Weapons (1977), chapter II; Carey Sublette, Nuclear Weapons FAQ, section 5

Sources

  1. Complete List of All U.S. Nuclear Weapons, Nuclear Weapon Archive (Carey Sublette)
  2. Mark 4 nuclear bomb, Wikipedia