Sellafield

(Redirected from Windscale)

Categories: Cumbria | Nuclear accidents | U.K. nuclear power plants

Sellafield is a village near the coast of the Irish Sea in Cumbria, England, close to the village and railway station of Seascale.

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The Sellafield facility on the Cumbrian coast, United Kingdom

[1] Sellafield is also the name of a nearby site, operated by British Nuclear Fuels Limited (BNFL), but owned since 1 April 2005 by the Nuclear Decommissioning Authority. It houses the Thorp nuclear fuel reprocessing plant, the Magnox nuclear fuel reprocessing plant, the inactive Calder Hall Magnox nuclear power station — the world's first commercial nuclear power station, and other older nuclear facilities.

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History

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Windscale

The Sellafield site is built on land that was formerly part of the Windscale nuclear site, which is named after a nearby village. Windscale was owned by the United Kingdom Atomic Energy Authority, but when part of it was transferred to BNFL, the transferred part was renamed as "Sellafield". The remainder of the site remains in the hands of the UKAEA and is still called Windscale.

Two air-cooled, graphite-moderated Windscale reactors constituted the first British weapons grade plutonium 239 production facility, built for the British nuclear weapons program in the late 40s and the 50s.

Windscale was also the site of the prototype British Advanced gas-cooled reactor. This reactor was shut down in 1981, and is now part of a pilot project to demonstrate techniques for safely decommissioning a nuclear reactor.

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Looking over the facility out to sea.
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The Windscale fire

Main article: Windscale fire

In 1957, a fire at one of the twin Windscale reactors caused the world's worst nuclear accident until the Chernobyl accident. An estimated 750 terabecquerels (TBq) (20,000 curies) of radioactive Iodine-131 were released, and milk and other produce from the surrounding farming areas had to be destroyed. For comparison, 250,000 terabecquerels or 250 petabecquerels (7 million curies) of Iodine-131 were released by Chernobyl, and only 0.55 terabecquerels (15 curies) of Iodine-131 by Three Mile Island.

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Calder Hall nuclear power station

Calder Hall was the world's first commercial nuclear power station. First connection to the grid was on 27 August 1956, and the plant was officially opened by Queen Elizabeth II on 17 October 1956 [2]. When the station closed on 31 March 2003, the first reactor had been in use for nearly 47 years [3].

Calder Hall had 4 Magnox reactors capable of generating 50 MWe of power each.

However in its early life it was primarily used to produce weapons-grade plutonium, with two fuel loads per year, with electricity production as a secondary purpose [4]. From 1964 it was mainly used on commercial fuel cycles, however it was not until April 1995 that the UK Government announced that all production of plutonium for weapons purposes had ceased [5].

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Plutonium records discrepency

On February 17, 2005, the UK Atomic Energy Authority reported that 29.6 kg (65.3 lb) of plutonium, enough to make seven nuclear bombs, was unaccounted for in auditing records at the Sellafield nuclear fuel reprocessing plant. The operating company, the British Nuclear Group, described this as a discrepancy in paper records and not as indicating any physical loss of material. They pointed out that the error amounted to about 0.5%, whereas IAEA regulations permit a discrepancy up to 1% as the amount of Plutonium recovered from the reprocessing process never precisely matches the pre-process estimates. The inventories in question were accepted as satisfactory by Euratom, the relevant regulatory agency. (BBC) (BNFL's response)

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2005 Thorp plant leak

Main article: Thorp nuclear fuel reprocessing plant

On April 19 2005 83,000 litres of radioactive waste was discovered to have leaked in the Thorp reprocessing plant from a cracked pipe into a huge stainless steel-lined concrete sump chamber built to contain leaks.

A discrepancy between the amount of material entering and exiting the Thorp processing system had first been noted in August 2004. Documentation of this finding was not passed up to the appropriate administrator.

Other indicators of a problem included a rise in temperature in the sump chamber and findings of radioactive fluid there, but these were ignored. The spill was recognized only after another audit suggested that further material was missing, prompting plant operators, after several days' delay, to train an automated camera on the faulty pipe and to actually measure the volume of liquid in the sump.

Responsible administrators have been disciplined. Some 19 tonnes of uranium and 160 kilograms of plutonium dissolved in nitric acid has been pumped from the sump vessel into a holding tank away from the now-closed Thorp plant. Radiation levels in the building preclude entry of humans and robotic repair of the leak would be prohibitively difficult. Officials are considering bypassing the faulty tank to resume operations.

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Controversy

The site has been the subject of much controversy because of discharges of radioactive material, mainly accidental but some alleged to have been deliberate.

One concern is discharges into the Irish Sea. In the hasty effort to build the 'British Bomb' in the 1940s and 50s radioactive waste was originally simply discharged by pipeline into the Irish Sea, which some claim remains one of the most heavily contaminated seas in the world. In his 1986 book The Worst accident in the world: Chernobyl, the end of the nuclear dream, Nigel Hawkes estimates that about 250 kg of plutonium have been deposited in the marine sediments surrounding the site during its lifetime. In addition, it has been shown that cattle and fish are contaminated with plutonium-239 and caesium-137, originating from the contaminated sediments. The plant at Sellafield is currently the most significant source of the long-lived radioactive element technetium in the environment; it is released during the reprocessing of nuclear fuel.

The installation to process spent fuel, which also processes material originating from other countries, is also controversial, as some fear that disposal is not being carried out safely, and the area will simply end up as a "dumping ground" for unwanted nuclear material from nuclear programs all over the world. This is of particular concern as the UK currently has no long term high level waste storage facilities.

German band Kraftwerk opened the song Radioactivity on their June 2005 live album Minimum-Maximum with an audio clip criticizing the Sellafield-2 reactor for radiation released into the atmosphere during typical operation and the dangers of reprocessing plutonium in regards to nuclear proliferation.

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Leukemia risks

In the early 1990s concern was raised in the UK about apparent clusters of leukemia near nuclear facilities. Detailed studies carried out by the Committee on Medical Aspects of Radiation in the Environment (COMARE) in 2003 found no evidence of raised childhood cancer around nuclear power plants, but did find an excess of leukaemia and non-Hodgkin's lymphoma (NHL) near other nuclear installations including Sellafield, AWE Burghfield and UKAEA Dounreay. COMARE's opinion is that "the excesses around Sellafield and Dounreay are unlikely to be due to chance, although there is not at present a convincing explanation for them". [6], [7]

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Irish objections

Sellafield has been a matter of some consternation across the Irish Sea, with the Irish Government and many members of the public angry at the danger that such a facility, of no benefit to Ireland, may pose to the country. The Irish government has indeed made formal complaints about the facility, and recently came to a friendly agreement with the British Government about the issue, as part of which the Radiological Protection Institute of Ireland, and the Irish police force (An Garda Síochána) are now allowed access to the site. However, Irish government policy remains that of seeking the closure of the facility.

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Norwegian objections

Similar sentiments are shared by the Norwegian government and population, because the prevailing sea currents transport radioactive materials leaked into the sea along the entire coast of Norway. Water samples show increases of up to ten times of such materials as Tc-99. This is of great concern to the fishing industry, because they fear for the reputation of Norwegian fish, even though the radiation levels have not been conclusively proved as dangerous for the fish. The Norwegian government is also seeking closure of the facility.

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References

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See also

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External links

fr:Sellafield nl:Sellafield (opwerkingsfabriek) sv:Sellafield (kärnkraftsanläggning)