The U.S. Department of Energy says there’s no sign that toxic waste has leaked into the environment from a double-shell storage tank at Eastern Washington’s Hanford Site, and it has resumed operations to remove the waste from the tank.
Last weekend, an alarm was set off when sensors detected that the level of sludge had risen to about 8 inches deep in the space between the inner and outer walls of Tank AY-102.
Leaks in the inner wall of that underground tank have been causing problems for years, and last month, workers began pumping the mixed radioactive and chemically toxic waste out of the tank for storage in other double-shell tanks. Even before the procedure began, planners determined there was a chance that disturbing the material in AY-102 could cause more waste to leak into the space between the walls.
“We were prepared for this event,” Glyn Trenchard, the Energy Department’s deputy assistant manager for Hanford’s tank farms, said Thursday in a statement.
The department said that monitoring and inspections turned up no visual or chemical indications that the leaked waste had made its way beyond the outer wall.
On Thursday, workers began returning the waste from the space between the walls back into the primary tank, using pumps that had been specially installed for that purpose. They also resumed operations to transfer the waste out of AY-102.
More than 95 percent of the 749,000 gallons of material that was in the tank has been removed already, the department said.
AY-102 is one of 28 double-shell tanks at Hanford that hold waste left over from the production of plutonium for nuclear weapons. The tanks were put into service between 1971 and 1986. AY-102 is one of the oldest tanks.
In 2012 and 2013, the U.S. Department of Energy reported leaks at seven of Hanford’s 177 storage tanks, including AY-102 and six single-shell tanks. The Washington State Department of Ecology has said the tank leaks pose “no immediate or near-term health risks” but raise concerns about future groundwater problems.
Update for 2 p.m. PT April 23: A typo has been corrected to make clear there is no indication of a leak into the environment.