Test No. 6

China · 1967 · 3.3 megatons · thermonuclear (hydrogen bomb)

Overview

First Chinese H-bomb test.

With a yield of 3.3 megatons, the Test No. 6 is 220× more powerful than the Hiroshima bomb. As a thermonuclear (hydrogen bomb) weapon, it derives its energy from a fission primary that ignites a much larger fusion secondary stage.

Test No. 6 Blast Effects

The table below shows the calculated radius of each effect zone for an air burst (optimal altitude, maximum blast spread) and a surface burst (ground level, with massive radioactive fallout). Formulas are scaling laws from The Effects of Nuclear Weapons (Glasstone & Dolan, 1977).

Effect zoneAir burstSurface burst
Fireball radius3.70 km2.96 km
Severe blast (20 PSI)6.98 km3.84 km
Moderate blast (5 PSI)14.93 km8.21 km
Light blast (1 PSI)42.46 km23.35 km
3rd-degree thermal burns18.56 km11.14 km
2nd-degree thermal burns33.25 km19.95 km
Lethal fallout zoneminimal~306.6 km

All values are 1-D ground-distance estimates from the detonation point. Real-world effects depend on terrain, weather, and building construction.

Run the Test No. 6 on a City

Use the interactive simulator to detonate the Test No. 6 on any city worldwide. Click any location on the map to see the fireball, blast, and thermal radii overlaid on real geography with population-density-based casualty estimates.

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FAQ

How big is the Test No. 6 blast radius?

In an air burst, the Test No. 6 produces a fireball roughly 3.70 km in radius and a 5 PSI moderate-blast zone of about 14.93 km — the area in which most residential buildings would collapse. The 1 PSI light-damage radius extends to roughly 42.46 km, where windows shatter.

What is the yield of the Test No. 6?

The Test No. 6 has a yield of 3.3 megatons of TNT equivalent. That is 220× more powerful than the Hiroshima bomb.

Is the Test No. 6 bigger than the Hiroshima bomb?

The Hiroshima bomb (Little Boy) had a yield of approximately 15 kilotons. The Test No. 6 at 3.3 megatons is 220× more powerful than the Hiroshima bomb.

What thermal burn radius does the Test No. 6 produce?

Thermal radiation from the Test No. 6 can cause 3rd-degree burns out to roughly 18.56 km and 2nd-degree burns out to 33.25 km in an air burst. Surface bursts reduce these radii by approximately 40 percent due to ground absorption.

Sources: declassified DOE/DOD records, FAS, SIPRI, Glasstone & Dolan. See the full Weapons Database or learn about the scientific methodology.