A double-shelled underground radioactive waste tank at Hanford that has already leaked through its inner shell might now be leaking through its outer shell into surrounding soil.
The 40-year-old Tank AY-102 was already being monitored because of a “slow leak,” said Lori Gamache, a spokeswoman for the U.S. Energy Department’s Office of River Protection.
Workers found an increased level of radioactive contamination under the tank during a routine inspection Thursday of the leak detection pit.
Washington Gov. Jay Inslee said in a statement that the situation “must be treated with the utmost seriousness.” Additional testing is expected to take several days, Inslee said.
“Our state experts confirm that there is no immediate public health threat,” Inslee said. “Given the relatively early detection of this potential leak, the river is not at immediate risk of contamination should it be determined that a leak has occurred outside the tank.”
In a statement Friday, Energy Secretary Ernest Moniz said that the Office of River Protection is testing to see if the increased radiation level is a result of leaks from Tank AY-102. The Energy Department will pump the liquid material from the tank if that is found to be the case.
River protection workers already are putting pumping infrastructure in place to do so, Moniz said.
While six single-shell tanks at Hanford were reported as leaking in February, Tank AY-102 would be the first double-shelled tank to leak through, said Erika Holmes, a spokeswoman for the state Department of Ecology. It had been reported last year as leaking into the space between its inner shell and secondary containment shell.
“(Double-shelled) tanks were considered safe storage because of their second shell that protects the environment from releases,” Holmes said.
A June 14 report by the Office of River Protection looked at the issue of whether the waste in AY-102 should be pumped to a sturdier double-shell tank. It would take more than a year and a half to get equipment in place that can pump the waste, the report said.
The state wants the Energy Department to accelerate removing the waste from the tank, according to an email from Holmes.
“Washington law is clear: ‘... within 24 hours after the detection of a leak or if the owner/operator demonstrates that it is not possible, at the earliest practicable time, remove as much of the waste as is necessary to prevent further release of dangerous waste to the environment and to allow inspection and repair of the tank system to be performed,” Holmes wrote.
Tank AY-102 holds about 850,000 gallons of waste. Between 300 and 500 gallons of waste had leaked into the space between the inner and outer shells, Holmes said.
In a news conference Friday, Inslee said Hanford was the primary topic during his conversation with Energy Secretary Ernest Moniz Thursday, a day after the secretary visited Hanford. Neither man knew of the leak at the time. Moniz called Inslee to tell him of the leak after he got back to Washington, D.C.
That type of communication has been lacking in previous energy secretaries, Inslee said.
The state will look at its legal options if the Energy Department doesn’t speed up its cleanup process, Inslee said. He called the federal government’s current plan “seriously deficient.”
“We intend to put maximum pressure on the federal government in the most effective way possible,” Inslee said. “I made clear to him that this is both a moral and legal obligation to the people of the state of Washington.”
Gamache said an engineering analysis team will conduct additional sampling and video inspection to determine the source of the contamination.
State and federal officials have long said leaking tanks at Hanford do not pose an immediate threat to the environment or public health. The tank is on the central plateau at Hanford about seven miles from the Columbia River.
“This is really, really bad,” said Tom Carpenter, executive director of the Seattle-based advocacy group Hanford Challenge. “They are going to pollute the ground and the groundwater with some of the nastiest stuff, and they don’t have a solution for it.”
Ken Niles of Oregon’s Energy Department said the latest leak is not an immediate risk.
“These last few months just seem like one body blow after another,” Niles said. “It’s one more thing to deal with among many at Hanford.”
Geoff Folsom: 509-582-1543; firstname.lastname@example.org; Twitter: @GeoffFolsom
The Associated Press contributed to this story