RICHLAND, Wash. - Workers at Hanford say the unusual radiation readings that led them to declare an emergency operations alert last month came from old contamination.
Inspectors say they found no evidence of a new leak from a waste removal system or its transfer hoses.
Hanford told its employees on Tuesday an investigation found insulating blankets, that were used to shield radiation on a small area, had shifted.
That caused the radiation readings to go up during routine monitoring.
Because the abnormal reading could have been caused by a leak, workers at the C Tank Farm were evacuated overnight back in August. Workers in central Hanford and near the K Reactors were ordered to take cover indoors.
Before work restarts this week, the hot spot will be recovered.