Blue Danube (nuclear weapon)

Blue Danube was the first operational British nuclear weapon. 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 it was built to fill. The RAF V bomber force was initially meant to use Blue Danube as their primary armament at a time when the first hydrogen bomb 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. For that reason the stockpile planned was for up to 800 bombs with yields of approx. 10-12 kilotons. V bomber bomb bays were sized to carry Blue Danube, the smallest-size nuclear bomb that was possible to design given the technology of the day (1947) when their plans were formulated.

Initial designs for the Blue Danube warhead were based on research derived from "Hurricane", the first British fission device (which was not designed nor employed as a weapon), tested in 1952. The actual Blue Danube warhead was proof-tested at the "Marcoo" (surface) and "Kite" (air-drop) nuclear trials sites in Maralinga, Australia, in late 1956. [http://nuclearweaponarchive.org/Uk/UKTesting.html]

Blue Danube added a ballistically shaped casing to the existing "Hurricane" physics package, 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 core, but all service versions were modified to use a composite plutonium/U-235 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; and secondly, to minimise the risk of predetonation, 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 came to fruition, largely because of the scarcity of fissile materials, and there is no evidence that any were seriously contemplated.

The first Blue Danube was delivered to stockpile at RAF Wittering 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 Vickers Valiant unit to integrate the Blue Danube nuclear weapon into RAF service. Declassified archives show that a total number of 58 were produced before production shifted in 1958 to the smaller and more capable Red Beard 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.

Major deficiencies with Blue Danube included the use of unreliable lead-acid accumulators to supply power to the firing circuits and radar altimeters. Later weapons used the more reliable ram-air turbine-generators or thermal batteries. Blue Danube was not really engineered as a weapon equipped to withstand the rigours of Service life. It was really a scientific experiment on a gigantic scale, which needed to be re-engineered to meet Service requirements. That re-engineered weapon became Red Beard. A similar account could be written of the first U.S. atomic bomb, Fat Man, which was quickly re-engineered after World War II.

Parts of a Blue Danube can be viewed by the public at Sellafield Visitors Centre in Cumbria.

ee also

* Rainbow Codes

References

*Moore. R; A Glossary of Nuclear Weapons. pub: Prospero, Journal of the British Rocketry Oral History Project (BROHP) Spring 2004.
*University of Southampton, Mountbatten Centre for International Studies at website
*http://www.mcis.soton.ac.uk/Site_Files/pdf/nuclear_history/glossary.pdf
*Various declassified official files at The National Archives, London.

External links

* [http://nuclearweaponarchive.org/Uk/UKTesting.html Photos of British nuclear tests - includes Blue Danube]