| Gerboise Blanche | |
| Map Type: | Algeria |
| Country: |  France |
| Test Series: | Reggane series |
| Test Site: | Reggane, French Algeria |
| Coordinates: | 26.1661°N -0.1025°W |
| Test Type: | Atmospheric |
| Test Altitude: | 0 m |
| Device Type: | A-bomb |
| Yield: | 3 kt (12.5 TJ) |
| Previous Test: | Gerboise Bleue |
| Next Test: | Gerboise Rouge |
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 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]
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.
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.
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]