'Reassurance' given by Dounreay after latest survey looking for nuclear particles on Sandside beach
A new survey has not found any evidence of a cluster of americium-rich hotspots on a public beach near Dounreay.
The assurance follows concern about the discovery of 12 particles with enhanced levels of the so-called daughter of plutonium on the private foreshore immediately off the nuclear plant between December 2016 and February 2018.
Traces of americium were also for the first time publicly recorded from a shard of reprocessed fuel unearthed from Sandside beach in January 2018.
The finds had raised fresh questions about Dounreay's historic pollution of the coastline.
Site operators have been recording radioactive fuel finds from the seabed and shoreline since the early 1980s.
But the focus on americium-241 – a metallic radio-toxin – has been a recent phenomenon.
The three-week survey carried out by radiation monitors from the plant this summer did not register new finds and, according to plant bosses, has allayed concern that there could be a cache of the rogue particles buried under the sand.
Dounreay managing director Mark Rouse said enhanced low gamma-ray energy detectors were deployed to scan for the presence of the radio-nuclide on Sandside and the west foreshore.
He said: "We wanted to evaluate the possibilities of there being more americium-rich particles present on the beaches.
"No particles were found during the surveys ... which provides reassurance that there was no resident cache of americium-rich, caesium-poor particles present and undetected on the beaches."
A total of 291 particles have been recovered from Sandside and 346 from the Dounreay foreshore.
An independent expert panel found that there is a one in 80 million chance of a regular beach goer at Sandside coming into contact with a particle which posed a realistic health hazard.
The Scottish Environment Protection Agency concluded the first americium-rich particle recovered from the foreshore in December 2016 would not have had a significant impact on human health, even in the unlikely event that the particle was swallowed.