Blue Danube was the first operational British

nuclear weapon A nuclear weapon is an explosive device that derives its destructive force from nuclear reactions, either fission (fission bomb) or a combination of fission and fusion reactions ( thermonuclear bomb), producing a nuclear explosion. Both bomb ...

. It also went by a variety of other names, including Smallboy, the Mk.1 Atom Bomb, Special Bomb and OR.1001, a reference to the

Operational Requirement An Operational Requirement, commonly abbreviated OR, was a United Kingdom (UK) Air Ministry document setting out the required characteristics for a future (i.e., as-yet unbuilt) military aircraft or weapon system. The numbered OR would describe ...

it was built to fill. The RAF

V bomber The "V bombers" were the Royal Air Force (RAF) aircraft during the 1950s and 1960s that comprised the United Kingdom's strategic nuclear strike force known officially as the V force or Bomber Command Main Force. The three models of strategic ...

force was initially meant to use Blue Danube as their primary armament at a time when the first

hydrogen bomb A thermonuclear weapon, fusion weapon or hydrogen bomb (H bomb) is a second-generation nuclear weapon design. Its greater sophistication affords it vastly greater destructive power than first-generation nuclear bombs, a more compact size, a lowe ...

had not been detonated, and the British military planners still believed that an atomic war could be fought and won using atomic bombs of similar yield to the

Hiroshima bomb "Little Boy" was the type of atomic bomb dropped on the Japanese city of Hiroshima on 6 August 1945 during World War II, making it the first nuclear weapon used in warfare. The bomb was dropped by the Boeing B-29 Superfortress ''Enola Gay'' ...

. For that reason the stockpile planned was for up to 800 bombs with yields of 10-12

kiloton TNT equivalent is a convention for expressing energy, typically used to describe the energy released in an explosion. The is a unit of energy defined by that convention to be , which is the approximate energy released in the detonation of a ...

s. V-bomber bomb bays were sized to carry Blue Danube, the smallest-size nuclear bomb that was possible to be designed given the technology of the day (1947) when their plans were formulated.

Design

Initial designs for the Blue Danube warhead were based on research derived from

Hurricane A tropical cyclone is a rapidly rotating storm system characterized by a low-pressure center, a closed low-level atmospheric circulation, strong winds, and a spiral arrangement of thunderstorms that produce heavy rain and squalls. Dep ...

, the first British fission device (which was neither designed nor employed as a weapon), tested in 1952. The actual Blue Danube warhead was proof-tested during

Operation Buffalo Operation Buffalo may refer to: * Operation Buffalo, 1944 military operation, part of the Battle of Anzio in WW2 * Operation Buffalo (1956), four open-air nuclear tests at Maralinga, South Australia * Operation Buffalo (1967), a Vietnam War opera ...

in autumn of 1956 at the ''Marcoo'' (surface) and ''Kite'' (air-drop) nuclear trials at

Maralinga Maralinga, in the remote western areas of South Australia, was the site, measuring about in area, of British nuclear tests in the mid-1950s. In January 1985 native title was granted to the Maralinga Tjarutja, a southern Pitjantjatjara Aborig ...

, Australia, by a team of Australian, British and Canadian scientists. During the ''Kite'' test on 11 October 1956, a

Vickers Valiant The Vickers Valiant was a British high-altitude jet bomber designed to carry nuclear weapons, and in the 1950s and 1960s was part of the Royal Air Force's " V bomber" strategic deterrent force. It was developed by Vickers-Armstrongs in respon ...

No. 49 Squadron RAF No. 49 Squadron was a bomber squadron of the Royal Air Force from 1938 to 1965. They were the first squadron to receive the Hampden in September 1938. The unit achieved fame through the Victoria Cross awarded to Rod Learoyd in 1940 and for its r ...

piloted by

Squadron Leader Squadron leader (Sqn Ldr in the RAF ; SQNLDR in the RAAF and RNZAF; formerly sometimes S/L in all services) is a commissioned rank in the Royal Air Force and the air forces of many countries which have historical British influence. It is als ...

Ted Flavell became the first British aircraft to drop a live atomic bomb. Blue Danube added a ballistically shaped casing to the existing Hurricane

physics package Nuclear weapon designs are physical, chemical, and engineering arrangements that cause the physics package of a nuclear weapon to detonate. There are three existing basic design types: * pure fission weapons, the simplest and least technically ...

, with four flip-out fins to ensure a stable ballistic trajectory from the planned release height of 50,000 ft. It initially used a

plutonium Plutonium is a radioactive chemical element with the symbol Pu and atomic number 94. It is an actinide metal of silvery-gray appearance that tarnishes when exposed to air, and forms a dull coating when oxidized. The element normally exh ...

core Core or cores may refer to: Science and technology * Core (anatomy), everything except the appendages * Core (manufacturing), used in casting and molding * Core (optical fiber), the signal-carrying portion of an optical fiber * Core, the centra ...

, but all service versions were modified to use a composite plutonium/

U-235 Uranium-235 (235U or U-235) is an isotope of uranium making up about 0.72% of natural uranium. Unlike the predominant isotope uranium-238, it is fissile, i.e., it can sustain a nuclear chain reaction. It is the only fissile isotope that exist ...

core, and a version was also tested with a uranium-only core. The service chiefs insisted on a yield of between 10-12 kt for two reasons: firstly, to minimise usage of scarce and expensive

fissile material In nuclear engineering, fissile material is material capable of sustaining a nuclear fission chain reaction. By definition, fissile material can sustain a chain reaction with neutrons of thermal energy. The predominant neutron energy may be t ...

; and secondly, to minimise the risk of

predetonation In nuclear physics, a nuclear chain reaction occurs when one single nuclear reaction causes an average of one or more subsequent nuclear reactions, thus leading to the possibility of a self-propagating series of these reactions. The specific nu ...

, a phenomenon then little understood, and the primary reason for using a composite core of concentric shells of plutonium and U-235. Although there were many plans for versions with higher yields, some up to 40 kt, none were developed, largely because of the scarcity of fissile materials, and there is no evidence that any were seriously contemplated.

Deployment

The first Blue Danube was delivered to stockpile at

RAF Wittering Royal Air Force Wittering or more simply RAF Wittering is a Royal Air Force station within the unitary authority area of Peterborough, Cambridgeshire and the unitary authority area of North Northamptonshire. Although Stamford in Lincolnshire ...

in November 1953 although there were no aircraft equipped to carry it until the following year. No. 1321 Flight RAF was established at RAF Wittering in April 1954 as a

unit to integrate the Blue Danube nuclear weapon into RAF service. The

Short Sperrin The Short SA.4 Sperrin (named after the Sperrin Mountains) was a British jet bomber design of the early 1950s, built by Short Brothers and Harland of Belfast. It first flew in 1951. From the onset, the design had been viewed as a fall-back opti ...

was also able to carry the Blue Danube and had been ordered as a fall-back option, in case the V-bomber projects proved unsuccessful. Declassified archives show that 58 Blue Danubes were produced before production shifted in 1958 to the smaller and more capable

Red Beard is a 1965 Japanese ''jidaigeki'' film co-written, edited, and directed by Akira Kurosawa, in his last collaboration with actor Toshiro Mifune. Based on Shūgorō Yamamoto's 1959 short story collection, '' Akahige Shinryōtan'', the film takes pl ...

weapon, which could accept the Blue Danube fissile core and also could be carried by much smaller aircraft. It seems unlikely that all 58 Blue Danube weapons were operational at any given time. Blue Danube was retired in 1962. Bomb storage facilities for the weapon were built at

RAF Barnham RAF Barnham (also called Barnham Camp) is a Royal Air Force station situated in the English county of Suffolk south of the Norfolk town of Thetford. It is located to the north of the village of Barnham on Thetford Heaths. The camp is a sat ...

Suffolk Suffolk () is a ceremonial county of England in East Anglia. It borders Norfolk to the north, Cambridgeshire to the west and Essex to the south; the North Sea lies to the east. The county town is Ipswich; other important towns include ...

and RAF Faldingworth in

Lincolnshire Lincolnshire (abbreviated Lincs.) is a Counties of England, county in the East Midlands of England, with a long coastline on the North Sea to the east. It borders Norfolk to the south-east, Cambridgeshire to the south, Rutland to the south-we ...

. These sites were built specifically to store bomb components in small buildings called 'hutches' with the high explosive elements of the weapons stored in dedicated storage areas.RAF Barnham (94 Maintenance Unit) Nuclear Bomb Store (Permanent Ammunition Depot)
Subterranea Britannica, 2003-11-09. Retrieved 2013-01-28.
Subterranea Britannica, 2003-11-01. Retrieved 2013-01-28. The storage facilities were probably closed in 1963 and put up for sale in 1966, the Barnham site becoming an industrial estate. The site at Barnham is a scheduled monument.

Problems

Major deficiencies with Blue Danube included the use of unreliable lead-acid accumulators to supply power to the firing circuits and

radar altimeter A radar altimeter (RA), also called a radio altimeter (RALT), electronic altimeter, reflection altimeter, or low-range radio altimeter (LRRA), measures altitude above the terrain presently beneath an aircraft or spacecraft by timing how long it t ...

s. Later weapons used the more reliable

ram-air turbine A ram air turbine (RAT) is a small wind turbine that is connected to a hydraulic pump, or electrical generator, installed in an aircraft and used as a power source. The RAT generates power from the airstream by ram pressure due to the speed o ...

-generators or thermal batteries. Blue Danube was not engineered as a weapon equipped to withstand the rigours of

service life A product's service life is its period of use in service. Several related terms describe more precisely a product's life, from the point of manufacture, storage, and distribution, and eventual use. Service life has been defined as "a product's ...

; it was a scientific experiment on a gigantic scale, which needed to be re-engineered to meet service requirements, resulting in

. The same could be said of the first U.S. atomic bomb,

Fat Man "Fat Man" (also known as Mark III) is the codename for the type of nuclear bomb the United States detonated over the Japanese city of Nagasaki on 9 August 1945. It was the second of the only two nuclear weapons ever used in warfare, the fir ...

, which was quickly re-engineered after

World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the World War II by country, vast majority of the world's countries—including all of the great power ...

Legacy

Parts of a Blue Danube could be viewed by the public at old Sellafield Visitors Centre in Cumbria, England. This centre closed in 2008. Retrieved 2020-09-27. A replica Blue Danube bomb is displayed in the Gorse Industrial Estate (the former site of the RAF Barnham facilities) in Suffolk.

References

Bibliography

* Leitch, Andy. "V-Force Arsenal: Weapons for the Valiant, Victor and Vulcan". ''

Air Enthusiast ''Air Enthusiast'' was a British, bi-monthly, aviation magazine, published by the Key Publishing group. Initially begun in 1974 as ''Air Enthusiast Quarterly'', the magazine was conceived as a historical adjunct to ''Air International'' maga ...

'' No. 107, September/October 2003. pp. 52–59. *Moore, Richard: "A Glossary of Nuclear Weapons". pub: Prospero, Journal of the British Rocketry Oral History Project (BROHP) Spring 2004.
Dr Richard Moore, University of Southampton, Mountbatten Centre for International Studies
*Various declassified official files at The National Archives, London.

External links

{{Strategic nuclear weapon systems of the United Kingdom Cold War weapons of the United Kingdom Nuclear bombs of the United Kingdom Military equipment introduced in the 1950s