Most deadly substance yet found at Dounreay

THE clean-up of the nuclear plant has uncovered the most potentially hazardous radio- active particle yet found at the site in 26 years of monitoring at the Sandside beach in Caithness.

The Dounreay Particles Advisory Group (DPAG) yesterday revealed that a remotely controlled vehicle deployed by diving contractors at the site had picked up a radioactive particle that measured 100 million becquerels (Bq) of radiation.

DPAG, which makes scientific and technical recommendations to the Scottish Environmental Protection Agency and the UK Atomic Energy Authority, considers radioactivity greater than one million Bq as a health risk. If left on the skin, a particle of above one million Bq could cause serious ulceration after one to two weeks.

A spokesman for Dounreay Site Restoration, the company responsible for the closure programme at the former fast reactor research and development centre, said the latest phase of the offshore clean-up had recovered 429 fragments from the seabed off Dounreay between August and October.

He said: "They were detected and retrieved by a remotely operated vehicle that spent 37 days systematically searching an area of seabed equivalent in size to 22 football pitches. It takes the total number of particles detected on the seabed and nearby coastline since 1983 to almost 2,000.

"A 60-metre-long barge LM Constructor, with a crew of 22, was stationed off Dounreay from 7 August until 17 October and covered 160,000 square metres of seabed.

"It retrieved 429 fragments, of which 81 were above the threshold for being classed as 'significant', as defined by Dounreay Particles Advisory Group in its assessment of potential health effects. The most radioactive fragment measured 100 million becquerels."