Chagai-I
Pakistan · 1998 · 40 kilotons · pure fission
Overview
First Pakistani nuclear test.
With a yield of 40 kilotons, the Chagai-I is 3× more powerful than the Hiroshima bomb. As a pure fission weapon, it derives its energy from nuclear fission of uranium or plutonium.
Chagai-I 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 zone | Air burst | Surface burst |
|---|---|---|
| Fireball radius | 0.63 km | 0.51 km |
| Severe blast (20 PSI) | 1.63 km | 0.90 km |
| Moderate blast (5 PSI) | 3.48 km | 1.91 km |
| Light blast (1 PSI) | 9.90 km | 5.44 km |
| 3rd-degree thermal burns | 3.04 km | 1.82 km |
| 2nd-degree thermal burns | 5.45 km | 3.27 km |
| Lethal fallout zone | minimal | ~52.5 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 Chagai-I on a City
Use the interactive simulator to detonate the Chagai-I 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.
🎯 Simulate Chagai-IRelated Weapons
FAQ
How big is the Chagai-I blast radius?
In an air burst, the Chagai-I produces a fireball roughly 0.63 km in radius and a 5 PSI moderate-blast zone of about 3.48 km — the area in which most residential buildings would collapse. The 1 PSI light-damage radius extends to roughly 9.90 km, where windows shatter.
What is the yield of the Chagai-I?
The Chagai-I has a yield of 40 kilotons of TNT equivalent. That is 3× more powerful than the Hiroshima bomb.
Is the Chagai-I bigger than the Hiroshima bomb?
The Hiroshima bomb (Little Boy) had a yield of approximately 15 kilotons. The Chagai-I at 40 kilotons is 3× more powerful than the Hiroshima bomb.
What thermal burn radius does the Chagai-I produce?
Thermal radiation from the Chagai-I can cause 3rd-degree burns out to roughly 3.04 km and 2nd-degree burns out to 5.45 km in an air burst. Surface bursts reduce these radii by approximately 40 percent due to ground absorption.