DOUNREAY was the centre of Britain’s research into fast-reactor technology in the 1960s, with the first of its reactors going live in 1958.

In 1962, its fast reactor was the first in the world to provide electricity to a national grid and it operated until 1977.

A damning safety audit by the Health and Safety Executive and Sepa in 1998 made 143 recommendations for improvements and a decommissioning programme was announced.

It is now recognised as the most complex nuclear site closure project in Europe, which will involve the dismantling of the site’s three reactors, starting in 2018.

This will include the removal of its famous “golf-ball” dome, which houses the fast reactor, as part of the final phase of the £1.6 billion clean-up of the old nuclear site.

Most of the radioactive materials held there, such as fuel, are being moved to other locations, including Sellafield in Cumbria, where it will be reprocessed or stored.

Also included in this is waste that comes from a series of nuclear reprocessing deals agreed by the Dounreay plant in the 1990s.

Some 800 fuel elements from power plants and research centres in Australia, Belgium, Germany and Italy were processed before a key chemical plant broke down in 1996.

Dounreay said at the time the resulting liquid waste would be mixed with cement, solidified in drums and returned to the countries of origin, in line with government commitments.

However, “substitution arrangements” allow for the exchange of nuclear waste with a “radiologically equivalent” amount of material from Sellafield.