Ivy Mike

Ivy Mike
The mushroom cloud from the Mike shot
Information
Country	United States
Test series	Operation Ivy
Test site	Enewetak
Date	November 1, 1952
Test type	Atmospheric
Yield	10 megatons of TNT

Ivy Mike was the codename given to the first test of a full-scale thermonuclear device, in which part of the explosive yield comes from nuclear fusion. It was detonated on November 1, 1952 by the United States on the island of Elugelab in Enewetak Atoll, in the Pacific Ocean, as part of Operation Ivy. It was the first full test of the Teller–Ulam design, a staged fusion device.

Due to its physical size and fusion fuel type (cryogenic liquid deuterium), the Mike device was not suitable for use as a deliverable weapon; it was intended as an extremely conservative proof of concept experiment to validate the concepts used for multi-megaton detonations. A simplified and lightened bomb version (the EC-16) was prepared and scheduled to be tested in operation Castle Yankee, as a backup in case the non-cryogenic "Shrimp" fusion device (tested in Castle Bravo) failed to work; that test was cancelled when the Bravo device was tested successfully, making the cryogenic designs obsolete.

The 82-ton "Mike" device was essentially a building that resembled a factory rather than a weapon. It has been reported that Soviet engineers derisively referred to Mike as a "thermonuclear installation". At its center, a very large cylindrical thermos flask or cryostat held the cryogenic deuterium fusion fuel. A regular fission bomb (the "primary") at one end was used to create the conditions needed to initiate the fusion reaction.