Chapelcross nuclear power station

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Chapelcross nuclear power station.

Chapelcross, previously the Chapelcross Processing Plant (CXPP), codenamed CANDLE, was a Magnox nuclear power plant located near the town of Annan in Dumfries and Galloway in south west Scotland. It was the sister plant to Calder Hall in Cumbria, England, both built and originally operated by the UKAEA (United Kingdom Atomic Energy Authority) Production Group.

The primary purpose of both plants was to produce weapons-grade plutonium for the UK's nuclear weapons programme (see WE.177), but they also generated electrical power on a commercial basis with a thermal efficiency of 19%.

Chapelcross operated from 1959 until 2004. At the time of its closure it was one of the oldest nuclear power plants in the United Kingdom. It consisted of 4 x 50MWe Magnox reactors generating a peak electric power output of 200MWe.

1 Nuclear weapons programme of the United Kingdom
2 Partial nuclear meltdown
3 Accident
4 Decommissioning
5 See also
6 External links

[edit] Nuclear weapons programme of the United Kingdom

Chapelcross nuclear power station.

Main article: Nuclear weapons and the United Kingdom

A tritium production facility called the Chapelcross Processing Plant (CXPP) operated on the site from 1980 until 2005, managed by BNFL for the UK Ministry of Defence. Liquid effluent was disposed of via a pipeline to the Solway Firth, and radioactive gases discharged to the atmosphere. All environmental discharges are subject to an annual discharge authorisation which is regulated by SEPA, the Scottish Environment Protection Agency. Because of involvement in the defence programme, the site was not subject to international safeguards until 1998[1].

Several thousand tonnes of MDU (Magnox Depleted Uranium) generated by historical reprocessing are stored in drums in a large building at Chapelcross. These are being over-packed with stainless steel drums and dispatched by road to Capenhurst for long-term storage as part of the wider programme of remediation and decommissioning funded by the Nuclear Decommissioning Authority (NDA) on UK nuclear sites. (See external links).

[edit] Partial nuclear meltdown

In May 1967, reactor 2 suffered a partial nuclear meltdown, when one fuel channel that was loaded with fuel elements under evaluation for the commercial reactor programme experienced a partial blockage, attributed to the presence of graphite debris (see fuel element failure). The fuel overheated and the Magnox cladding failed, causing contamination to be deposited in one region of the core. The reactor was restarted in 1969 after successful clean-out operations and was the final reactor to cease operation. [2] [3].

[edit] Accident

Chapelcross nuclear power station.

In 2001, during a refuelling campaign on reactor 3, a basket of discharged fuel elements (see nuclear fuel cycle) was dropped. An investigation was carried out by the Nuclear Installations Inspectorate (NII) and a report is available describing the incident (see External links).

[edit] Decommissioning

Defuelling is due to begin at Chapelcross in March 2007. The nuclear fuel will be removed and taken to Sellafield in Cumbria for reprocessing.

The strategy for decommissioning the Magnox nuclear power stations is known as deferred site clearance. It plans for total site clearance around 100 years after the initial shutdown[4]