Take cover alert lifted at Hanford nuclear site

RICHLAND, Wash. – A take cover order that lasted about four hours has been lifted for Hanford nuclear reservation workers.

Workers were ordered to take cover indoors Friday morning in an area near the center of the 580-square-mile federal site north of Richland.

A team surveyed the area where steam had unexpectedly been spotted coming from a building at one end of a tunnel storing radioactive waste shortly before 6 a.m.

No evidence was found that any radioactive particles had escaped the tunnel to contaminate the air.

Lights and cameras already placed in the tunnel showed steam in its interior as the latest layer of concrete-like grout poured inside the tunnel cured. The curing process generates heat and moisture.

When the warm air left the tunnel and hit the cool morning air, steam was visible, according to the Department of Energy.

Workers were ordered, as a precaution, to take cover indoors with windows and doors closed and ventilation systems shut down.

They will be returning to their planned work tasks this afternoon, according to the Department of Energy.

Over the next few days, crews will evaluate the opening in the building where steam escaped. Then work to stabilize the tunnel by filling it with grout is expected to resume.

Since the first of the month when grouting began, workers have placed about 9,000 cubic yards of grout in the tunnel. It is estimated to be almost 25 percent of the grout that will be needed to fill the tunnel to prevent a possible collapse.