Environmental authorities in Scotland have said that an accidental release of radioactive dust from a nuclear site "contravened multiple" regulatory conditions, according to reports.
The contaminated dust vented out of a uranium recovery plant at Dounreay—a nuclear research center which is in the process of being decommissioned—earlier this year after a valve failed during a system test in February, the BBC reported.
This caused a "disturbance" of contaminated dust in the ventilation system and a subsequent discharge into the facility itself and the atmosphere.
Following the incident, the Scottish Environment Protection Authority (SEPA) conducted an investigation which has concluded that while the discharge was well within the site's authorized limits, the operator—Dounreay Site Restoration Ltd (DSRL)—was still in breach of regulations, The Press and Journal reported.
"The increased discharge of radioactivity to the environment resulting from this incident was less than one percent of the relevant authorized gaseous discharge limit and there was no breach of discharge limits," Stewart Ballantine from SEPA said in a statement.
"Although the environmental impact of the discharge is considered to be very low, SEPA's investigation into the incident concluded that DSRL contravened multiple conditions of its radioactive substances authorisation," he said.
SEPA has now issued DSRL with a regulatory notice containing steps that the operator must take to address the breaches by October 2020.
In response, a DSRL spokesperson 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 environmental impact is considered 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 had conducted an investigation earlier this year into alleged shortcomings in the system used at Dounreay to prevent radioactive substances polluting the local environment, The Press and Journal reported. This probe resulted in site operators being issued with a "final warning letter."
The Dounreay site—located in the far north of Scotland—was operational between 1954 and 1994. The complex comprises some 300 facilities and structures which are expected to be decommissioned entirely by the early 2030s.
However, Dounreay's operators say that the land at the site will not be safe to use for other purposes for another 300 years due to the risks of potential radioactive contamination, the BBC reported.
