World Bulletin/News Desk
Six underground storage tanks at the Hanford Nuclear Reservation along the Columbia River in Washington state were recently found to be leaking radioactive waste, but there is no immediate risk to human health, state and federal officials said on Friday.
The seeping waste adds to decades of soil contamination caused by leaking storage tanks at Hanford in the past and threatens to further taint groundwater below the site but poses no near-term danger of polluting the Columbia River, officials said.
The newly discovered leaks were revealed by Governor Jay Inslee a week after the U.S. Energy Department disclosed that radioactive waste was found to be escaping from one tank at Hanford.
Inslee said he was informed on Friday by outgoing U.S. Energy Secretary Steven Chu that a total of six of the aging, single-walled tanks were leaking radioactive waste.
"It points to the age of the tanks and how there's going to be an increased probability of this happening in the future," said Suzanne Dahl, the tank waste treatment manager for the state Department of Ecology. "When waste is in the tanks, it's manageable. Once it's out of the tanks and in the soil, it's much harder to manage it, remove it, and down the road you're adding to contamination in the groundwater that already exists."
DECLINING LIQUID LEVELS
The Energy Department said a week ago that declining liquid levels in one tank at Hanford showed it was leaking at a rate of 150 to 300 gallons (568 to 1,136 liters) per year.
It subsequently informed state officials that a second, larger tank was leaking at about the same rate, while the four smaller tanks were leaking at a rate of about 15 gallons per year, Dahl said.
The 586-square-mile (1,518-square-km) Hanford Nuclear Reservation was established near the town of Hanford in 1943 as part of the Manhattan Project, the U.S. government program that developed the first atomic bombs.
Previous Cold War era weapons production at the site resulted in more than 43 million cubic yards of radioactive waste and 130 million cubic yards of contaminated soil and debris, according to the U.S. Environmental Protection Agency, which says that approximately 475 billion gallons of contaminated water have been discharged into the soil.
As part of the cleanup, as much remaining liquid waste as possible was pumped out of the older single-shell tanks into sturdier double-walled tanks in a process completed in 2005, Dahl said.
But sludge, mud-like waste and pockets of liquid remained behind in the older tanks, and it is that material that was found to be seeping in the soil again from six tanks, she said. According to the DOE, one of those tanks currently holds about 447,000 gallons of radioactive sludge.
Under the multibillion-dollar cleanup plan, the waste from the storage tanks will eventually be processed in a special treatment plant that will immobilize the waste in a glass-like material that can be safely disposed of underground in stainless steel canisters.
But Dahl said construction of the waste treatment plant was still years away.