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Atomic bomb store on Thetford Heath

A Scheduled Monument in Barnham, Suffolk

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Coordinates

Latitude: 52.3856 / 52°23'8"N

Longitude: 0.7194 / 0°43'9"E

OS Eastings: 585161.003185

OS Northings: 279873.38173

OS Grid: TL851798

Mapcode National: GBR QC8.GP0

Mapcode Global: VHKCK.F94K

Entry Name: Atomic bomb store on Thetford Heath

Scheduled Date: 20 May 2003

Source: Historic England

Source ID: 1020781

English Heritage Legacy ID: 30608

County: Suffolk

Civil Parish: Barnham

Traditional County: Suffolk

Lieutenancy Area (Ceremonial County): Suffolk

Church of England Parish: Barnham St Gregory

Church of England Diocese: St.Edmundsbury and Ipswich

Details

The monument includes a bomb store which was one of two designed and built in
the 1950s for the storage and maintenance of Britain's atomic bombs. The
storage compound covers an area of around 9ha and is pentagonal in plan,
enclosed by a double fence with a patrol path between. Within this enclosure
the various storage and maintenance units for the components of the bombs are
laid out in a functionally designed landscape. A metalled track leads from
Elvedon Road, 30m to the south, to the entrance, and on either side of the
gate to the main compound is an outer fenced enclosure containing various
ancillary buildings and other structures, chiefly relating to site security.

Planning of the facility is thought to have begun in 1952 and the site was
purchased by the Air Ministry in 1954. Building work was substantially
complete by August 1955 and the station, known as RAF Barnham, became
operational at the beginning of September in the following year. It was
commanded by No.40 Group and formed part of No.94 Maintenance Unit, with
headquarters at RAF Honington, approximately 6km to the south east. It was
intended that this group should supply airfields at Honington in Suffolk and
Marham and Watton in Norfolk. In the original design the ancillary buildings
to either side of the main entrance were situated between the inner and outer
fences of the main compound, but at a later date, probably in 1958, the fences
here were moved back and the present outer enclosure constructed. The early
free-fall bombs for which the storage system was designed became obsolete with
the introduction of the stand-off missile Blue Steel in late 1962, and storage
of weapons here probably ceased in 1963. The site was sold into private
ownership by the RAF in late 1965, but the layout and most of the original
structures remain.

The bombs originally stored here were large, measuring 7.3m in length by 1.52m
in diameter and weighing 4636kg. The two principal components were the
plutonium core and the machined lenses of high explosive which surrounded the
core and, when detonated, would cause it to implode to form a critical mass.
The fissile cores were stored separately from the outer casing containing the
explosive lenses and the electronic and mechanical components. These bombs
required careful maintenance and monitoring. Some of the nuclear components
were highly unstable and the cores containing them had to be reassembled at
frequent intervals. The high explosives also had to be kept in a controlled
environment.

The track giving access to the storage area is enclosed by a wire fence
carried on concrete posts. Entry, at the southern end, was controlled by
double gates, and immediately behind these, to the right of the track, is a
picket post for an armed guard. Beyond the picket post, also to the right of
the track, are bays for a motor transport shed, fuel compound and two standby
generator buildings. The track runs due north, then bends eastwards at right
angles towards the gate of the outer enclosure. The metal rails for the
original electric inner gate, moved back when this side of the storage
compound was remodelled, can be seen in the surface of the track. Most of the
buildings within the outer enclosure are of prefabricated construction. On the
east side of the track, immediately to the right of the original gate, is a
hut which housed the duty officer and a small brick building which was the
standby generator house, with a three sided brick structure behind it to
contain a transformer and sub-station. To the east of these is a small brick
building which was the small arms ammunition store. Buildings on the opposite
side accommodated the RAF Police dog section. Alongside the track is an L-
shaped hut which contained the guard room and a control centre, with a small
mess and sleeping accommodation for the dog handler, who was the only person
billeted on site. Behind this is a small building used as the meat preparation
store for the dogs, and beyond it, in the angle of the outer enclosure, the
concrete base of the dog compound, on which the outline of the individual runs
can be traced. Other buildings on this side include the former fire station,
the telephone exchange and a gym. In the southern angle of the enclosure is a
water tank and pump.

The main enclosure is aligned on a north east-south west axis, with the
entrance at the south western angle of the pentagon. The two fences are set
about 22m apart, and the area between was lit by lamps on concrete posts. The
outer fence is of wire mesh supported on concrete posts which are angled
outward at the top, and a perimeter path runs around the inner side. At the
mid point along the north west, north east and east sides the fence line is
offset to form a triangular bastion about 5.2m wide and 1.5m deep, allowing
patrolling guards to sight along the external faces of the fence. At the
western, northern, north eastern and south eastern angles there are steel
framed observation towers 8.2m high with roofed cabins on which search lights
were mounted, and there is a fifth observation tower inside the fence,
immediately to the east of the entrance gate. The inner fence is of concrete
panels slotted into concrete uprights. Immediately to the west of the inner
gate which is set in this inner fence, is a small building thought to have
been a picket post.

The storage and maintenance buildings radiate from a sub-oval circuit road
around a central area enclosed by an earthen bank. The three buildings to
house the non-nuclear components of the bombs were almost identical in plan
and were positioned symmetrically, one at the north eastern end of the circuit
and one on either side. The building on the north western side was demolished
following a fire in the 1980s, leaving only the concrete floor slab, but the
other two survive. All three are surrounded by earthen banks 4.42m high
revetted by reinforced concrete walls at the ends abutting the roadway. The
two surviving buildings are constructed of reinforced concrete columns and
beams, with walls of precast concrete blocks, and are rectangular in plan,
measuring 57.97m by 18.29m internally. Two longitudinal rows of columns
support the reinforced concrete roof slabs, dividing the interior into a
central corridor 7.62m wide with aisles of 11 bays on either side. Originally
these bays were open, but dividing walls have been inserted to convert them
into workshops. The floors, which are included in the scheduling, are surfaced
with a patented gritless compound to reduce the risk of accidental sparks.
The access doors at the end of the buildings opening onto the road are 3.05m
wide and 3.66m high, and there are emergency exits at the opposite ends.
Flanking the entrances are buildings which contained the heating and air
conditioning plant for the store. The bombs were loaded and unloaded by means
of a gantry extending above the roadway, with reinforced concrete support
columns and beams, to which were attached a steel joist runway beam,
originally fitted with a hoist.

The fissile cores were stored in 54 small, rectangular, kiosk-like buildings
or `hutches' arrayed in four groups between and to the south of the
non-nuclear component stores. The buildings in each group are linked by a
rectilinear system of footpaths leading off a primary path which opens off the
main road circuit. The paths are fenced by tubular steel railings and where
the ground rises, in the north eastern part of the site and at the entrance to
the path to the south western group, they are cut level into the surrounding
surface. The areas were lit by concrete lampposts. Free standing walls, set
around the central area within the main road circuit, face the entrances to
each of the path systems.

The buildings themselves are constructed of concrete, with foundations 0.91m
thick, cavity walls, and flat, overhanging roofs covered with bituminous felt.
The walls are rendered internally with gritless plaster, with four small
ventilators inset at the sides and to the rear. The doors are of wood
protected externally by a steel sheet, and are secured by a combination lock
and internal, vertical locking bar operated by an external handle. Attached to
the frame above the doors were spring loaded electrical contacts, probably to
signal whether the doors were open or closed to an external control board at
the gate. Many of the buildings retain the remains of other electrical
fittings, including small bore pipes, junction boxes and switch boxes. The
fissile cores were contained in stainless steel vessels sunken into the floors
The vessels have been removed but the shafts into which they were sunk remain.
These are cylindrical, about 0.54m deep and 0.44m in diameter, with a
shallower, rectangular depression 0.09m deep and measuring 0.27m wide by 0.21m
at the lip, forming a keyhole shape. The buildings are of two types. The
majority measure 2.54m by 2.39m in plan and have a single shaft in the centre
of the floor. Nine of them, grouped in threes in the northern, north eastern
and south western arrays respectively, are slightly larger, with two shafts in
the floors. It is thought that the single shafts were for plutonium cores, and
the double shafts for cobalt cores. At some stage the double shafts were
sealed with asphalt, but this has been removed and the shafts re-exposed in
one of the buildings in the northern array. A small brick building shielded on
three sides by a brick wall and situated alongside the path leading to the
northern array is thought to have been used for the inspection of cores.

The other maintenance buildings are situated opposite to or near the entrance
to the main enclosure and accessed by bypass loops off the main circuit road.
Immediately opposite the inner gate is a rectangular building constructed of
concrete blocks, with a porch and self contained battery charging room at the
front. The original building has been extended to the east. Behind this, and
separated from it by an earthen bank, is a larger and taller building of
similar construction to the non-nuclear component stores, with air lock
porches at either end and separate plant rooms and a dark room to the rear.
This was probably used for the assembly or maintenance of warheads, and the
entrances are shielded by high, free standing breeze block walls. Another
large building of brick stands to the west of the entrance. This was
constructed in 1959 and is described in the design drawings as `Inspection and
Repair Workshop'.

Other features of the inner enclosure include three large, static water
tanks located one on either side of the north eastern non-nuclear
component store and one to the west of the south eastern array of fissile
core stores.

A number of features are excluded from the scheduling, these are: the wire
mesh of the fences, wooden fences, fence posts which post-date the
occupation of the site by the RAF, service poles in use and supports for
signs post-dating the occupation of the site by the RAF, an electrical
substation in use, inspection chambers in use, fuel tanks, the
superstructure of the non-nuclear component stores and the associated
gantries and all other roofed buildings other than kiosks for the storage of
the fissile cores. The original floors of the non-nuclear stores, the ground
plans of the excluded buildings and the ground beneath all these features
are, however, included.


MAP EXTRACT
The site of the monument is shown on the attached map extract.

Source: Historic England

Reasons for Scheduling

The archaeological remains of the Cold War (1946-1989) are the physical
manifestation of the global division between capitalism and communism that
shaped the history of the late 20th century. Nuclear weapons were the
defining technology of the Cold War, firstly as atomic fission weapons,
and later as more powerful hydrogen fusion weapons. Both types are
technologically complex, expensive and dangerous products which required
specialised, secure storage and handling facilities. These took the form
of purpose built storage and maintenance units and special storage areas,
on airfields where aircraft cleared to carry nuclear weapons were
permanently stationed or might be deployed in time of war. The evolution
of nuclear bomb stores in England illustrates changing deployment
strategies throughout the Cold War by the Royal Air Force and the United
States Air Force - both by its Strategic Air Command deterrent forces and
by its tactical forces committed to NATO. The siting of nuclear bomb
stores on airfields, for example, demonstrates NATO's willingness to store
nuclear weapons close to the units that would use them.
Initial RAF plans to hold atomic bombs at two central stores were quickly
overtaken by the need for faster response times, and small atomic bomb
stores were instead provided on nine of the ten main V-bomber nuclear
strike airfields. These stores were initially supported by other central
stores and so were configured to hold no more than twelve bombs. In the
first generation of atomic bomb stores there is a close correlation
between the physical infrastructure and the bombs they were designed to
house, and the crudity of early atomic bombs is reflected in the design
and size of their stores. As nuclear weapons became smaller, and required
less on-site maintenance, storage conditions changed too. The power of
these weapons is manifest in special security arrangements, including
double or triple fences, watchtowers, security lights and entry control
points.
Many early RAF airfield stores were enlarged by the Supplementary Storage
Areas (SSAs) offering a far higher degree of protection to the weapons,
and reflecting the increasing robustness of nuclear weapons technology. In
the late 1980s vaults were installed in a number of Hardened Aircraft
Shelters to hold ready to use bombs.
Nuclear bomb stores, or their key components, where these reflect their
diversity of form, are considered to be of national importance where they
survive well and display sufficient of the plan form or layout to provide
for a full interpretation of the monument, illustrating the processes of
storage, maintenance and transportation that occurred there. A selection
of these is deemed sufficient for designation.

The atomic bomb store and servicing facility on Thetford Heath is one of the
two central stores built in the mid-1950s to coincide with the deployment by
the RAF of its first operational atomic bomb, codenamed `Blue Danube', and as
such it is of particular interest. The site and its structures were purposely
designed to handle this bomb, and this is reflected in the design and
landscaping of the complex, as well as in the stores designed to hold the very
large body of the bomb, and the small `hutches' to hold fissile cores. Many
other original features survive, including security installations, and in its
extensive physical remains and internal layout the site provides a good
example of a first generation nuclear bomb store and evidence for the handling
procedures. The monument also illustrates the poor serviceability of early
nuclear weapons policy, which envisaged no more than six weapons being held on
a single airfield, with any reloads being supplied from the central bomb
stores.

Source: Historic England

Sources

Other
Cocroft, W, Cold War Project Survey Report RAF Barnham, (1998)

Source: Historic England

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