W31

Missile warheadUnited StatesImplosion fission

No freely licensed photo of this device yet.

Yield · TNT equivalent1–40 kt

Key specs

Country: United States
Design: Implosion fission
Type: Missile warhead
Weight: 420 kg
Length: 1 m
Diameter: 740 mm
In service: 1958–1989
Number built: 4,500

Overview

A warhead of 1 to 40 kt for the Nike Hercules surface-to-air missile and the Honest John artillery rocket, also used as an atomic demolition munition. About 4,500 were built; the last left service in 1989.

Effect radii: estimates

Calculated for 40 kt

Fireball, maximum radius: ≈ 270 m
Initial radiation, 500 rem (5 Sv): ≈ 1.7 km
Blast 5 psi: most buildings collapse: ≈ 2.4 km
Thermal: third-degree burns: ≈ 3 km
Blast 1 psi: windows shatter: ≈ 7.5 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

Complete List of All U.S. Nuclear Weapons, Nuclear Weapon Archive (Carey Sublette)
W31, Wikipedia