Here is a timeline of Dounreay's controversial recent past.

1998:
31 March - The government announces it will spend more than �200m cleaning a contaminated shaft at Dounreay. The pit was sealed more than 20 years ago but is still leaking radioactivity.

The plant is a major employer in the area

22 April - It is announced that Dounreay is to receive a total of 5.1kg of uranium, including 800g of waste fuel flown in an American transport plane from the former Soviet state of Georgia.

16 May - The Health and Safety Executive announces a sweeping review of safety at Dounreay. It follows an incident when a mechanical digger accidentally cut through power cables paralysing the plant.

2 June - It emerges that 170kg of weapons-grade enriched uranium from the nuclear plant cannot be accounted for.

5 June - The government announces that Dounreay is to be closed, although the necessary decontamination work will take many years. The plant employs 1,400 staff.

1999:
28 January - An investigation confirms weapons-grade uranium has gone missing at the nuclear plant. However the energy minister said the amount lost is tiny and "acceptable" by modern standards.

Operators deny cover-ups

28 May - Five workers at Dounreay have to be monitored for possible radioactive contamination. They had been handling a package of uranium waste when it burst in to flames.

1 August - The operators of Dounreay are accused of delaying the news that they have found another radioactive "hot-spot" near the site. A Dounreay spokesman said he was waiting for the results of tests before making the news public.

2000:
7 March - A report praises the management at Dounreay for the progress made in improving safety. However the House of Commons trade and industry committee warns that much still needs to be done.

1 August - The operators of the Caithness plant accept "full responsibility" for breaches of safety which caused two major alerts. The UK Atomic Energy Authority is fined �101,000 after three workers are contaminated and a main power cable is cut.

40-year-old waste in storage

28 May - Another radioactive particle is found on a beach close to the Dounreay plant. It is the 12th particle to be found there since 1983. Nine have been discovered in the last 12 months.

2001:
18 July - The government rules out any future role for the Dounreay plant as a nuclear reprocessing site. The energy minister said that he thinks a refurbishment of the plant's reprocessing systems is not merited.

2002:
22 January - Dounreay is given a clean bill of health by inspectors following a safety review. However the Nuclear Installations Inspector said the ability to decommission the site fully will depend on the ability to recruit sufficient numbers of staff.