Gerboise Blanche

Gerboise Blanche (or Opération Gerboise Blanche) was the codename of the second French nuclear test. It was conducted by the Nuclear Experiments Operational Group (GOEN), a unit of the Joint Special Weapons Command^[1] on 1 April 1960, at the Saharan Military Experiments Centre near Reggane, French Algeria in the Sahara desert region of Tanezrouft, during the Algerian War.^[2][3]

Gerboise Blanche
Location of the test site
Information
Country	France
Test series	Reggane series
Test site	Reggane, French Algeria
Coordinates	26°09′58″N 00°06′09″W
Date	1 April 1960; 65 years ago (1960-04-01)
Test type	Atmospheric
Test altitude	0 m
Device type	A-bomb
Yield	3 kt (12.5 TJ)[a]
Test chronology
← Gerboise Bleue Gerboise Rouge →

Name

Gerboise is the French word for jerboa, a desert rodent found in the Sahara. The color white (Blanche) adjuncted is said to come from the second colour of the French Flag.^[4]

Test

Explosion

Gerboise Blanche operation was carried out 3 months after the success of the first test, Gerboise Bleue. Unlike the first attempt and the two others that were to come, this bomb was placed a few kilometres from ground zero, and detonated on a concrete pad.^[5] This was a voluntary act of the authorities as they feared the usual test site would have been too contaminated for the next tests.^[6]

On 1 April 1960 at 6:17:00 UTC,^[7] the 1,250 kg plutonium filled fission bomb was detonated with a yield of 3 kt.^[8] The explosion created a crater that was later filled in.^[9] The Ministry of the Armed Forces subsequently asserted that the test paved the way for the miniaturization of this type of weapon, and that the lower yield was voluntary.^[10] A 2001 document of the National Assembly confirmed this assertion while claiming that the bomb was an "emergency device" that would have been used had Gerboise Bleue failed.^[6]

Synthesis of the aerial nuclear tests at the CSEM^[9]

Fallout

Initial monitoring reported a radiation dose of 100 rad/h at 3 km from ground zero one hour after the blast, and 0.3 rad/h at 45 km. Monitoring at Khartoum, around 3,400 km from Reggane, reported 10⁻¹⁰ Ci/m³.^[8]

In 2005, the Algerian government asked for a study to assess the radioactivity of former nuclear testing sites. The International Atomic Energy Agency published the report suggesting that Gerboise Blanche explosion site had the highest Caesium-137 surface levels of the four tests, with a residual surface activity between 0.02 and 3.0 MBq/m² over a surface area of about 1 km².^[11] The same report showed that while the fallout of the 3 other tests of the Reggane series were contained in circular areas of less than 1 km in diameter, the fallout of Gerboise blanche expanded south-west over a distance of more than 6 km.^[12]

See also

• Agate (French first underground A-bomb)
• Canopus (French first atmospheric H-bomb)
• Force de Frappe
• List of states with nuclear weapons
• Nuclear weapons and France
• History of nuclear weapons

Notes

1. Physicist Pierre Billaud reported a yield of 4 kt (16.7 TJ). See External links.