Operation Grapple

Grapple
First British H-bomb test - Operation Grapple X Round C1, which took place over Kiritimati.
Information
Country	United Kingdom
Test site	Kiritimati (Christmas Island), Kiribati; Malden Island, Kiribati
Period	1957-1958
Number of tests	9
Test type	air drop, balloon
Max. yield	3 megatonnes of TNT (13 PJ)
Navigation
Previous test series	Operation Antler
Next test series	Operation Vixen

Operation Grapple, and operations Grapple X, Grapple Y, and Grapple Z, were the names of British nuclear weapons tests of very early hydrogen bombs. These tests were carried out from 1956 until 1958 at Malden Island and Christmas Island in the Central Pacific Ocean. Nine nuclear explosions were executed during these series of nuclear weapon tests, culminating in the United Kingdom's becoming the third recognised possessor of thermonuclear weapons.

All nuclear bombs used during Operation Grapple, Grapple X, Grapple Y, and Grapple Z were exploded high in the atmosphere, rather than being detonated on the ground, in order to reduce the production of nuclear fallout.

The unproven H-bomb designs being developed by British weaponeers required full-scale testing of their capabilities, hence Operation Grapple was carried out as a massive military operation in the Central Pacific, and this was the largest British military operation carried out since World War II. The preparations for Operation Grapple, including building the necessary structures on Kiritimati, began at the end of May 1956. About 1,200 civilians and servicemen were sent to Kiritimati during 1956.

The first deliveries to Kiritimati were made by the troopship Devonshire, which steamed to the Central Pacific from East Asia and took construction troops aboard at Fiji. These men had flown there from the UK on commercial airliners. The first project on Kiritimati, which was finished in October, was to rebuild the main runway at the airport. The majority of troops and civilians were then flown in from the UK, via Canada and Hawaii, in chartered airliners. The original troops began to be flown out in mid-1957.