Washington state: Possible radioactive leak at Hanford tank farm
SEATTLE -- As part of the biggest, costliest environmental cleanup project in the nation’s history—disposing of 53 million gallons of radioactive waste at the Hanford Nuclear Reservation in Washington state—one thing was supposed to be sure: Waste stored in the sturdy, double-wall steel tanks that hold part of the toxic ooze wasn’t going anywhere.
But that reassurance has been thrown into question with the discovery of a 3-foot-long piece of radioactive material between the inner and outer steel walls of one of the storage tanks, prompting new worries at the troubled cleanup site.
“We’re taking it seriously, and we’re doing an investigation so we can better understand what it is,” Department of Energy spokeswoman Lori Gamache told the Los Angeles Times.
The discovery marks the first time material has been found outside the inner wall of one of the site’s 28 double-shell tanks, thought to be relatively secure interim storage for the radioactive material generated when Hanford was one of the nation’s major atomic production facilities. It opened in 1943 and began a gradual shutdown in 1964. Cleanup started in 1989.
The $12.2-billion cleanup project eventually aims to turn most of the waste stored at Hanford into glass rods at a high-tech vitrification plant scheduled to be operational in 2019, assuming the formidable design and engineering hurdles can be overcome.
In the meantime, plant engineers have been gathering waste stored in the facility’s 149 aging, leaky single-wall storage tanks and redepositing them in the double-shell tanks for safekeeping.
Over the years, more than 1 million gallons of waste has leaked out of 67 single-wall tanks into the surrounding soil.
“There’s been this presumption that the double-shell tanks at least are sound and won’t fail, and they’ll be there for us,” said Tom Carpenter of the advocacy group Hanford Challenge. Several days ago the group obtained a memo from the cleanup site detailing discovery of the mysterious substance.
“This changes everything. It is alarming that there is now solid evidence that Hanford double-shell has leaked,” Carpenter said in a separate statement on the discovery.
The 42-year-old tank, known as AY-102, holds about 857,000 gallons of radioactive and other toxic chemical waste, much of it removed several years ago from a single-shell storage tank where it was considered unsafe. Workers who relocated the material fell ill simply from inhaling the fumes, Carpenter said.
Department of Energy officials said none of the material has leaked outside the outer steel wall or the concrete casing that surrounds the structure, and there is no present hazard to workers or groundwater.
They said they were trying to determine whether the material leaked from the inner tank or oozed from a nearby pit into the space between the two walls, known as the annulus.
“There’s no evidence of it leaking the liquid from the inner shell right now,” Gamache said.
The material – a mound 2 feet by 3 feet by 8 inches -- is dry and doesn’t appear to be growing. It was discovered during a routine video inspection of the annulus conducted last month from a viewpoint not normally used.
The possibility that it could have come as overflow from a nearby pit arises because a pipe runs into the annulus from the pit, Gamache said.
But Carpenter, who has talked extensively with workers at Hanford and was briefed Tuesday by one of the Department of Energy’s senior officials at the tank farm, said he believed the evidence was strong that there was a leak.
“I know Hanford would like it not to be so. But the people I’m talking to at the Hanford site say, no, it really does look like a leak,” he said. “From what I’m being told and looking at the pictures, it appears it’s coming from under the tank and going up. Which is a far cry from it coming from the pit.”
Gamache said an initial sample of the material revealed that “the contamination levels were higher than expected” and it definitely contained radioactive waste. “There wasn’t enough material to fully characterize the material, so we’re preparing to pull another sample. That will probably happen around the mid-September time frame,” she said.
Carpenter said that if the inner tank leaked, it would probably prompt the need to reevaluate expectations that the tanks could safely act as interim storage vessels for several decades.
“These are the tanks that are considered sound, that will last for another 40 years, and if that’s not true, then they’re going to have to consider building new tanks at a minimum,” he said. “They may also need to develop the ability to move waste around much quicker than they do now.”
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