The clean-up of Dounreay is expected to take until 2033

It covers a 12-month period from 1 April, 2005 and includes details on waste removed but also the highest dose of radiation received by a worker.

The UK Atomic Energy Authority (UKAEA) reported 20 "safety events", with one serious spillage recorded.

It also said that its clean-up at the 140-acre site over the 12 months had come in 7% below budget.

Dounreay Review 2005/06 has been produced by UKAEA.

Waste spillage

It reports that 14 buildings were demolished, 18 laboratories cleaned out, 20 glove-boxes and 25 fume-cupboards removed, a shielded cell was decommissioned and 150 tonnes of sodium was destroyed.

Dismantling work generated almost 250 drums of solid intermediate-level radioactive waste. This was then checked and consigned for storage.

More than 5,000 drums of solid low-level radioactive waste were also processed for disposal.

There were 20 "safety events" recorded.

UKAEA said only a spillage in a waste treatment plant was serious enough to be registered on the International Nuclear Event Scale.

The scale is a means for communicating quickly to the public the safety significance of events reported at nuclear installations.

It was designed by a group of experts convened jointly in 1989 by the International Atomic Energy Agency and the Nuclear Energy Agency of the Organisation for Economic Co-operation and Development.

Local beaches

One member of staff was found to have the highest dose of radiation over the 12 months. The authority said it had represented 16% of the annual legal limit for radiation exposure.

Four radioactive particles were detected during monitoring of almost five million square metres of local beaches.

A further 41 were retrieved from the seabed.