New equipment in hunts for rogue Dounreay particles
New vehicles are being used to monitor for radioactive particles at three beaches near a Scottish nuclear power plant.
Sandside, Strathy and Murkle are regularly checked for pollution from Dounreay.
Tiny particles linked to the reprocessing of nuclear fuel rods were flushed into the sea through the site's liquid discharge pipe in the 1970s.
Thousands of the fragments have been found and removed from beaches.
The Metrac H5 all-terrain vehicles, already used for monitoring beaches near Sellafield in Cumbria, are now patrolling Sandside, Strathy and Murkle.
They have replaced Hill Cat ATVs, which have been used for a number of years but will be retained for use in peak periods of particle detection work.
Sandside is the most frequently checked of the beaches, while Strathy and Murkle are looked at in May and November.
Dounreay Site Restoration Limited expects the monitoring to continue for several years.