The Sellafield nuclear reprocessing site, in Cumbria, north-west England, told all non-essential employees not to come to work after the elevated levels were picked up by a monitor at the north end of the site.
"Levels of radioactivity detected are above naturally occurring radiation but well below that which would call for any actions to be taken by the workforce on or off the site," said a statement posted on Sellafield’s website.
"The site is at normal status and employees and operational plants are continuing to operate as investigations continue. All our facilities have positively confirmed there are no abnormal conditions and are operating normally."
The plant is on the coast of the Irish Sea about 300 miles northwest of London and employs more than 10,000 staff. Despite the decreased workforce, it said the facility was still operating a full capacity.
Britain’s nuclear decommissioning authority told Reuters that it was unclear where the radiation is coming from.
A spokesman for the U.K.’s Department of Energy and Climate Change said it was in constant contact with Sellafield, and that there was no reason to believe the situation was more serious than the operator had claimed, Reuters reported.
Sellafield processes spent fuel and no longer produces power from nuclear. It is undergoing a decommissioning and dismantling program, run by a consortium of British company Amec, French group Areva, and U.S. firm URS.
Reuters contributed to this report.
This is some I didn’t hear on the BBC World Service for the half-hour I was listening to it over night Pacific time.