THE discovery of radioactive contamination has halted the construction of a substation for the high-voltage electricity cable linking Orkney to the mainland.
The site, located at Dounreay near Thurso in Caithness, is part of SSEN’s £900 million Orkney-Caithness 220kV link project, which includes the substation initiative.
The radiation traces, estimated to be 80 years old, are believed to have come from military aircraft instruments abandoned in the area around the time of the Second World War.
The aircraft dials were painted with a substance containing radium-226 (RA-226), a known cancer-causing substance. A high level of radium gives higher chances for bone, liver and breast cancer.
The Scottish Environment Protection Agency (Sepa) and SSEN said the zone has been restricted and is secured.
An SSEN spokesperson said: "As a further precaution, all works on site have been temporarily suspended whilst further tests and assessments take place."
SSEN said that Sepa was notified and they will continue to work with them, and other contractors, going forward.
A spokesperson for Sepa said: “As part of the planning process for the Scottish & Southern Electricity Networks Orkney-Caithness high-voltage cabling project, Sepa identified the need for monitoring for radioactivity to be undertaken at the site where a sub-station will be constructed.”
Sepa explained that the monitoring was essential due to the proximity to the former RAF-Dounreay base.
“Following the identification of radium contamination at the site, SSEN has stopped work while it acquires an Environmental (Scotland) Authorisations Regulations 2018 (EASR) permit," Sepa added.
“An EASR permit is needed due to the presence of radium contamination at depth and the planned excavation works, beyond these depths."
In 1990, Sepa discovered radium for the first time at Dalgety Bay foreshore. It originated from residue from elements of military aircraft burned or buried during WW2.
Radium became popular in the 20th century and acted as an additive in products such as toothpaste, creams or food. It was subsequently used to paint watch dials and aircraft instruments until the 1970s when it was discovered that radium is a carcinogenic element.
