Contaminated dust release probed at Dounreay nuclear site
The accidental release of radioactively contaminated dust at Dounreay "contravened multiple" regulatory conditions, investigators have said.
It has emerged that dust was disturbed during testing of a ventilation system at the nuclear complex in February.
Investigators said there was no breach of discharge limits and any environmental impact was "very low".
However, they said conditions of Dounreay's radioactive substances authorisation were contravened.
The Scottish Environment Protection Agency (Sepa) investigated the incident at the former experimental nuclear power plant near Thurso in Caithness.
Sepa was informed of the release of dust by Dounreay Site Restoration Ltd (DSRL).
DSRL said: "A regulatory notice has been received from Sepa following its investigation into an event from February in one of our facilities.
"While we welcome Sepa's assessment that there was no breach of discharge limits and that the environmental impact is considered to be very low, we take such events seriously.
"Environmental compliance is a high priority for us and we are making good progress against an action plan developed in response."
Sepa confirmed that a regulatory notice had been issued that "outlines the steps DSRL is required to take to address the identified contraventions."
The site of Britain's former centre of nuclear fast reactor research and development, Dounreay is in the process of being decommissioned and the land cleaned up.