The plant, which went into operation in 1959, was originally planned to be phased out March next year, but due to technical problems the deadline has been pushed forward. One of the four reactors at the plant has remained out of service since an accident in 2001, and the rest have been switched off since February.

Continued Magnox operation not justified
“We have now reached the position at Chapelcross where we are clear that continuing to deploy the resources needed to maintain generation from the three remaining – by modern standards – relatively small reactors at this site cannot be justified commercially,” said Chapelcross site manager Dr. Bob Clayton.

Many of the 450 workers at the site will be retained for several years while decommissioning takes place and reactors are made safe. The work force will now concentrate on de-fuelling the reactors before beginning on demolition at the site near the city of Annan.

The reactors at Chapelcross were the first of the first generation of British nuclear reactors that later came to be called Magnox reactors. In total, 26 such reactors were built in the United Kingdom. Except for Chapelcross and its sister power plant, Calder Hall at Sellafield, all of the reactors were constructed between 1960 and 1970. As a consequence of the Chapelcross closure, there will only be eight Magnox reactors left in operation, dispersed among four different plants. The United Kingdom is the only country in the world that operates this kind of reactors.

In a statement today, Mark Morant, Managing Director of the group’s Reactor Sites business praised the site and its workforce: “As the world’s currently longest serving nuclear power station, Chapelcross has earned a rightful place in the record books as a faithful provider of electricity to South West Scotland and the North of England.

An early weapons producer
The Chapelcross plant was actually constructed to operate both as an electricity generator and a producer of weapons grade plutonium, and for many years played a central role in the UK nuclear weapons programme, producing plutonium both for atomic and hydrogen bombs. It is believed that the reactors produced weapons-grade plutonium for the British army as late as in 1978—1979.

For the last fifteen years Chapelcross has been operating purely as an electricity production plant. Still the Scottish Campaign for Nuclear disarmament, or SCND, argues that Chapelcross continued to play a military role—until it was shut down today—through the delivery of tritium to the military.

Modern nuclear weapons contain small quantities of tritium—a radioactive material that plays a key role in the thermonuclear process of a hydrogen bomb, and is also used to boost the yield of atomic bombs. It is used on British Trident warheads. Tritium is a radioactive material with a short half-life of 12 years. Because it decays so quickly it has to be replaced. The tritium in British nuclear weapons is replaced after seven or eight years. The military, therefore, demands a constant supply of tritium—and in according to the SCND this has been delivered by Chapelcross.

5,000 tonnes of Depleted Uranium are stored at Chapelcross. This was part of a massive military stockpile of this material which has been controversially used in conventional weapons. In 1998 Britain, announced that the material at Chapelcross would no longer be considered as military material and would be placed under EURATOM and IAEA safeguards.

End to Magnox generation
Over the last years BNFL has had considerable technical problems with its old Magnox reactors. Since 2000, four different Magnox plants, consisting of 16 different reactors, have been shut down. All of the remaining eight Magnox reactors are expected to closes within the next six years.

BNFL though hopes to build four to six new light-water reactors in the same location that some of the shut down Magnox reactors now stand. These new reactors have been developed by the BNFL-owned company Westinghouse, and are called the AP 600 and the AP 1000. But the construction of new nuclear power plants in the UK has been put on ice for the time being.

The British government has proposed a goal to reduce the country’s CO2 emissions by 60 percent by 2020. But in order to achieve this, the government would like to pursue alternative sources of energy, not nuclear sources. However, the British government has said it is open for a new assessment of nuclear power at a later point in time.