Bldg 84 strip.jpg

Nuclear Test Detection - French Sahara

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The Plate Store (Building 84)

 

When originally called the 'Plate Store’ this Orford Ness building was used to store components (airplanes or parts of them) that from 1938 were tested against bullets etc. as part of “Lethality and Vulnerability” trials. 

 

In the late 50’s, the Plate Store was also called Building 84 (under an AWRE numbering system) and from it, trials were held to assess the effectiveness of 'Over The Horizon Radar’ (OTHR) technology in the detection of long distance, atmospheric nuclear detonations.

 

The electronics systems and the aerial involved were designed and built by local AWRE staff, with major components being purchased from a "second hand dealer in Bournemouth" and then customised and assembled on site.

 

On 13 February 1960, the first French nuclear detonation from Reggane, in the Sahara Desert, took place and this was detected by this locally developed OTHR system. Our research suggests that the second detonation (1 April 1960) was also detected, but this has yet to be confirmed. This OTHR installation was the first of a number of OTHR systems that were built on the Ness. These included two confirmed installations on Orford Ness: ’Cobra Mist’ and ‘Chaplain’ (which was installed on a 50m diameter concrete ring) and possibly a fourth Ness installation called Zinnia. Research continues.

 

The French nuclear tests from the Sahara 

For detailed information see https://en.wikipedia.org/wiki/Gerboise_Bleue_(nuclear_test) 

 

The programme for the above-ground nuclear tests was:

  • 13 February 1960 : Gerboise Bleue ( "Blue Jerboa") : 70kt

  •    1 April 1960 : Gerboise Blanche ("White Jerboa") : <5kt

  • 27 December 1960 : Gerboise Rouge ("Red Jerboa") <5kt

  • 25 April 1962 : Gerboise Verte ("Green Jerboa") <1kt

Shortly after the Gerboise Verte test the French moved their nuclear testing to the mountainous In Ekker Sahara region, which housed an underground facility. Later tests were carried out in French Polynesia from 1966 to 1996.

 

Aerials with undefined purpose

B84 is located in the marsh area adjacent to the River Ore. An 1965 AWRE site plan shows a number of different aerials located in the surrounding marsh. See Drawings button above

Only one rhombic aerial was used in the detection of the French Tests. The purposes of the other aerials, including a large rhombic and an 'open V’ aerial, remain unknown.

 

Research continues and a complete report is to follow.

Drawings - click image to enlarge view  - for full size please contact IRGON 

 

Photographs - click image to enlarge view - for full size please contact IRGON 

 
 

Graphics - click image to enlarge view

Nuclear Test Detection French Sahara

Nuclear Test Detection French Sahara

Extract from AWRE 1965 site map © Crown Copyright / AWE 2021 Contains public sector information licensed under the Open Government Licence v3.0.

Nuclear Test Detection French Sahara

Nuclear Test Detection French Sahara

View of building 84 looking toward Orford from The Street

Nuclear Test Detection French Sahara

Nuclear Test Detection French Sahara

Foundations of quad aerial near building 84 - purpose of this aerial is unknown

Nuclear Test Detection French Sahara

Nuclear Test Detection French Sahara

Photo showing location of B84 in marsh area near River Ore

Nuclear Test Detection French Sahara

Nuclear Test Detection French Sahara

CGI Image showing B84 in Marsh area as at 1960

 

Nuclear test Detection -  French Sahara Tests  Location - Satellite view