The latest trawl of the contaminated seabed recovered 38 high-hazard fragments of reactor fuel.
Each has over one million bequerels of radioactivity and has the potential to cause significant harm to human health. They have been detected and retrieved by a remote control robot launched from a barge anchored just off the shoreline.
Contractor Land and Marine left at the weekend after completing a nine-week operation.
In all, 351 particles of reprocessed fuel were found and brought back to the atom plant for analysis.
It is the high-hazard ones which plant contractors DSRL is targeting in its multi-million pound drive to help clean up the local coastline.
The pollution stems from historic sloppy waste practices at the former fast reactor site.
A 22-strong team worked round-the-clock, scanning an area the size of 36 international football pitches. The robot - the size of a small bulldozer - worked at depths of up to 30 metres.
Last year’s survey unearthed over 400 particles, including 74 in the high-hazard category. The latest trawl brings the total of seabed particles recovered to 1884.
A further 481 have been recovered, nearly all from the Dounreay foreshore and Sandside each, near Reay. A two-mile fishing exclusion zone has been in place since the seabed pollution was detected in 1997. Source