The U.S. Department of Energy announced Thursday an underground radioactive and dangerous chemical waste storage tank at the Hanford Site in Southeast Washington is leaking.
The Washington state Department of Ecology’s Nuclear Waste Program, along with the U.S. Environmental Protection Agency, oversees Energy’s cleanup of Hanford.
“It’s a serious matter whenever a Hanford tank leaks its radioactive and dangerous chemical waste,” Ecology Director Laura Watson said. “Based on the information we have right now, the leak poses no immediate increased risk to workers or the public, but it adds to the ongoing environmental threat at Hanford.”
Tank B-109, which is at least 75 years old, is estimated to be leaking 3.5 gallons a day, or nearly 1,300 gallons per year.
Ecology has been concerned with this tank and tracking it for more than a year, when a formal leak assessment first began. B-109 is leaking into an area where other tanks have already leaked 200,000 gallons into the soil.
B-109 is miles away from the Columbia River, and the water table is 210-240 feet below the tank.
An estimated 1,700 gallons have leaked into the soil from B-109 dating back to March 2019.
Hanford tanks contain widely varying volumes of mixed waste (waste with both radioactive components and dangerous chemicals), each with a unique blend of constituents.
“This leak is adding to the estimated one million gallons of tank waste already in the soil across the Hanford site,” Watson said. “This highlights the critical need for resources to address Hanford’s aging tanks, which will continue to fail and leak over time.”
Ecology was notified about a year ago that Energy had started a formal leak assessment for B-109. At that time, Energy said the tank’s levels were decreasing but it was not sure why. Ecology has been tracking the situation and was notified Thursday (April 29), that Energy had determined that the tank is in fact leaking.
Ecology has authority under the Tri-Party Agreement, which governs the Hanford clean-up, to take immediate action in response to a leaking single-shell tank only if it is “necessary to abate an imminent and substantial endangerment to public health or welfare or the environment.”
The state’s initial assessment is that, while any leak is a serious issue, there isn’t an imminent danger.
The next step is for Ecology to try to reach agreement with Energy about the best path forward. If the two agencies can’t agree, Ecology retains the authority to take an enforcement action and require specific actions to address the leak.
Tank B-109 is part of the 12-tank B Farm, which is one of Hanford’s oldest tank farms and is co-located with the BX and BY tank farms. B-109 has an estimated 15,000 gallons of liquid waste as part of its total waste volume of about 123,000 gallons. An estimated 200,000 gallons of waste already has leaked from other tanks in the B-BX-BY tank farm complex.
B-109 began receiving waste in 1946 and was taken out of service in 1976. It was still full of waste at that time, but no further waste was added. The tank was interim stabilized and declared sound in 1985.
This tank received bismuth phosphate waste, evaporator slurry bottoms, Plutonium-Uranium Extraction Plant (PUREX) cladding waste, and B-Plant ion exchange waste.