RDS-27

Missile warheadSoviet UnionLayered fission–fusion

No freely licensed photo of this device yet.

Yield · TNT equivalent250 kt

Key specs

Country: Soviet Union
Design: Layered fission–fusion
Type: Missile warhead

Overview

A weaponised version of the RDS-6s “layer cake” using lithium deuteride, reduced to 250 kt and intended as the warhead of the R-7, the first intercontinental ballistic missile. It was air-dropped over Semipalatinsk in November 1955.

Effect radii: estimates

Calculated for 250 kt

Fireball, maximum radius: ≈ 550 m
Initial radiation, 500 rem (5 Sv): ≈ 2.4 km
Blast 5 psi: most buildings collapse: ≈ 4.5 km
Thermal: third-degree burns: ≈ 6.4 km
Blast 1 psi: windows shatter: ≈ 14 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

Tests and use

Date	Event	Site	Yield
Nov 6, 1955	RDS-27	Semipalatinsk Test Site, Kazakh SSR	250 kt

Sources

Soviet Nuclear Test Summary, Nuclear Weapon Archive (Carey Sublette)
Joe 4, Wikipedia