Dounreay beaches particle hunt kit 'modified'
Equipment used to find radioactive particles on beaches near a nuclear power site has been modified so it can better detect the fragments.
The tiny particles were discharged from Dounreay in Caithness into the sea in the 1970s.
For several years surrounding beaches have been monitored and more than 200 particles removed.
Following the discovery of a particle with an unusual radioactive signal, the kit has been made more "sensitive".
Fragments with gamma radiation have made up the majority of finds on the beaches.
But in February last year one dominated by beta radiation, which is less easily detected, was found.
Following discussion with independent experts, regulators and monitoring contractor Nuvia, the plastic covering that protects the detection sensors has been replaced with a carbon fibre covering.
Dounreay Site Restoration Limited (DSRL), which is leading the demolition of Dounreay and commissioned the monitoring, said the change would improve the work.
A spokesperson said: "Carbon fibre is less dense than plastic, improving the capability of the equipment to detect other such particles that may be present."
DSRL also said the frequency of monitoring could be reduced and even discontinued at some beaches in the future.
It said this would be done in line with advice from the Scottish Environment Protection Agency (Sepa).
Meanwhile, work to clean up the seabed near Dounreay will not take place this year.
A remotely-operated vehicle was used to recover the harmful particles every summer since August 2008.
DSRL said it had agreed to clean up an area of 148 acres (60ha) and by September had removed fragments from 222 acres (90ha).
The company said a total of 2200 particles were recovered from seabed.