The Atomic Energy Authority is facing criminal charges over two separate alleged incidents at its Dounreay nuclear plant in the north of Scotland.

The first involved the contamination of three workers by radioactivity in 1995.

The second relates to a mains power failure three years later.

Procurator fiscal Alasdair MacDonald confirmed that both cases are due to be called at Dornoch Sheriff Court, in Sutherland, on 29 March.

The charges relating to the 1995 incident follows a lengthy investigation by officials of government watchdog body, the Nuclear Installations Inspectorate.

Routine checks

They involve alleged breaches of the "ionising radiation" regulations of the Health and Safety at Work Act.

Despite calling in experts from outside bodies, it is understood that the authority has been unable to pinpoint why the three workers became exposed to radioactivity.

The contamination was discovered during routine body checks on Dounreay staff working in potential radiation zones.

The authority has also been charged under summary procedure over the mains power failure at the site's Fuel Cycle Area in May, 1998.

The bucket of an excavator sliced through the underground electricity supply cable.

Contracts ban

The failure sparked off a series of events which included the government stepping in to ban the authority form accepting any further "commercial" contracts for reprocessing irradiated nuclear fuel rods from overseas operators.

It also led to the widest-ranging study of Dounreay's plants and facilities in the complex's 40-year history by the two main regulators.

Their report strongly recommended that improvements by made in 143 separate cases to bring Dounreay in line with modern safety standards.

Until the power failure Dounreay's Fuel Cycle Area used to routinely deal with some the most radioactive materials known.

The authority was ordered to shut the area following the incident, pending essential safety improvements.

The smallest atomic fuel reprossessing plant, code-named D 1204, is to remain closed and be decommissioned.