Atomic Weapons Research Establishment. Orford ... - English Heritage

Laboratories 1, 2 and 3
To the west, the first development phase comprised three main structures, Laboratory
1 F3/123, Laboratory 2 F1/125, and Laboratory 3 F2/126/128, also associated with
Laboratory 1 was the Control Room F4/127/67. To move heavy construction plant
across Stony Ditch it appears that a shingle causeway was created to the southeast of the
First World War Barracks C1/18. From this point a concrete road was laid towards the
Control Room F4/124 and another toward Laboratory 2 F1/125. As discussed above a
new road was also laid from the existing bridging point at the north eastern end of The
Street towards the Black Beacon G1/40. This is a well constructed road with kerbs to
either side and is surfaced in asphalt and it was probably along this road that the test
devices were brought. From the headquarters area the road heads southwest towards
the Control Room F4 after which point it splits, a southerly branch heading towards to
Laboratory 2 F1/125 and a northerly arm towards Laboratories 1 F3/123 and 3 F2/126.
At the time these laboratories were designed the standard casing for large air dropped
nuclear devices was the one used for the first generation of operational nuclear weapons
known as Blue Danube. It was large and measured 24ft (7.3m) in length with a maximum
diameter of 5ft (1.52m) and weighed 10,000lb (4636kg), its size determined by the
dimensions of its warhead. Britain’s first operational warhead, the Mark I, also contained
around 2.50 tons of conventional high explosives (Cocroft and Thomas 2003, 30). As
discussed above this casing had been extensively proven by trial drops over Orford Ness,
and there was probably also an element of expediency and economy to use casings
that were already held in stock for a number of later warheads. Given its large size, for
trials work it was able to accommodate newer models of warheads, such as the interim
megaton device Orange Herald. Combined with a Blue Danube casing it was known
as Violet Club or Knobkerry and was issued briefly to the RAF between 1958 and 1959.
The size of the Blue Danube casing, the relatively large amounts of conventional high
explosives used within 1950s nuclear warheads, the proposed trial routines and safety all
contributed to the form of the test buildings.
Travelling from the headquarters area the first major structure of this period
encountered is Laboratory 1, or the Large Vibration Laboratory F3/123 (Figures 10
and 49). As its name suggests the function of this laboratory was to gently vibrate a
fully assembled weapon, minus its fissile core, to simulate the types of stresses it might
undergo while being transported by road or in the air. Laboratory 1 is a massive
reinforced concrete structure with a large central bay measuring 30.69m (100ft) by 9.13m
(30ft) and was designed to mitigate against the effects of an accidental explosion. Its
concrete walls were given extra mass by the shingle traverse placed around them, which
would tend to force blast vertically rather than laterally. The roof was also a relatively
weak structure comprising nine steel W-shaped trusses and clad in aluminium sheeting,
insulated with cork and covered in weather proof felt. The original requirement for this
building was to test the Mark I atomic bomb and the Red Beard tactical weapon. It was
envisaged that two chambers would be required, one for the assembly of the weapon
and drop-tests with an impact loading of up to 200 tons. As it name implies in a droptest
a weapon would be released from given height to simulate a ground handling mishap.
A second chamber would be required for vibration tests (TNA: PRO AVIA 65/1258).
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10 - 2009