Thermonuclear · United States · 1954
Castle Bravo
Castle Bravo test (“Shrimp”)
The most powerful American nuclear test. An unexpected reaction of lithium-7 multiplied the yield by 2.5.
See Castle Bravo in the 3D simulator- Yield
- 15 MtDocumented
- Energy
- 62.8 PJ
- Mass
- 10.7 tDocumented
- Dimensions
- 4.56 m · Ø 1.37 mDocumented
- Type
- “Dry” thermonuclear device (lithium deuteride)
- Period
- Cold War
- Status
- Single test
Castle Bravo releases about 1,000 times the energy of Little Boy (Hiroshima, 1945).
Key points
- A fireball about 7 km across in less than one second.
- The first “dry” thermonuclear weapon, without liquid hydrogen: the path to transportable bombs.
History
Fallout contaminated inhabited atolls (Rongelap, Utirik) and the crew of the Japanese fishing boat Daigo Fukuryū Maru, causing an international crisis.
- 1 March 1954 Castle Bravo test.
- March 1954 Late evacuation of the inhabitants of Rongelap.
- 1963 Partial Test Ban Treaty on atmospheric testing.
How does it work?
A thermonuclear weapon (“H-bomb”) first uses a fission explosion, which creates the extreme conditions needed to fuse light nuclei (hydrogen isotopes).
Fusion releases a lot of energy per unit of mass and is not limited by a critical mass: this is what makes the megaton range and beyond possible.
One megaton (Mt) is the energy of one million tons of TNT, about 4.2 × 10¹⁵ joules.
Deliberately general explanations: the application provides no design or manufacturing information.
Frequently asked questions
How powerful is Castle Bravo?
Castle Bravo has an estimated yield of 15 Mt of TNT equivalent, about 62.8 PJ of energy.
What is the history of Castle Bravo?
Single test, on 1 March 1954, at Bikini (Marshall Islands). Fallout contaminated inhabited atolls (Rongelap, Utirik) and the crew of the Japanese fishing boat Daigo Fukuryū Maru, causing an international crisis.
What does the Castle Bravo explosion look like?
The Bomb Simulator shows the fireball, shock wave and cloud of Castle Bravo at real scale, over Paris, London or New York, with the sources and reliability of each value.
Sources
- Castle Bravo — Wikipedia (overview, to be cross-checked)
- The Effects of Nuclear Weapons, 3rd ed. (Glasstone & Dolan, 1977) — U.S. DoD / DOE (OSTI)
Other weapons
- Trinity — 25 kt
- Little Boy — 15 kt
- Fat Man — 21 kt
- RDS-1 — 22 kt
- Hurricane — 25 kt
- RDS-6s — 400 kt
- Gerboise Bleue — 70 kt
- 596 — 22 kt
- Davy Crockett — 20 t
- Ivy Mike — 10.4 Mt
- RDS-37 — 1.6 Mt
- Mk 17 — 15 Mt
This application is an educational tool. The animations and effect zones are simplified representations meant to illustrate orders of magnitude. They are neither a prediction of the effects of a real weapon nor a military planning tool.