The Department of Energy said Thursday a single-shell underground radioactive waste tank at its Hanford Site in Washington state is probably leaking at the rate of about 3.5 gallons daily.
The DOE concluded the B-109 tank is leaking after monthly monitoring “detected a small drop in the level of liquid in the tank, and a formal leak assessment began in July 2020” and finished this week by contractor Washington River Protection Solutions, the federal agency said in a statement on its Hanford website.
“There is no increased health or safety risk to the Hanford workforce or the public,” a DOE spokesperson said in the online statement.
“It’s a serious matter whenever a Hanford tank leaks its radioactive and dangerous chemical waste,” Washington Ecology Director Laura Watson said in a press release. “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.”
At a rate of 3.5 gallons per day, the tank could be leaking nearly 1,300 gallons in a year, according to the Washington Ecology release. The 75-year tank is leaking into an area, part of the 12-tank B Farm that is co-located with two other tank farms, where other tanks have already leaked 200,000 gallons into the soil, according to the state agency.
“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.”
Five years ago, Washington River Protection Solutions started pumping sludge from tank AY-102, the first of 28 double-shell tanks to be built at Hanford, after it developed a leak.
“Contamination in this area is not new and mitigation actions have been in place for decades,” according to DOE. Tank B-109 was previously emptied of pumpable liquids, leaving a very small amount of liquid waste in the tank, the agency said.
There are groundwater pump-and-treat systems nearby designed to ensure leaked contaminants are removed from the ground before reaching the Columbia River. “DOE estimates it could take more than 25 years for any contamination from Tank B-109 to reach the water table, which would then be captured and removed by the pump and treat systems,” according to the agency.
In a Thursday letter to Hanford employees, DOE’s Richland Operations Office said it has notified both the Washington Department of Ecology and the U.S. Environmental Protection Agency.
The next step is for Ecology to try to reach agreement with DOE about the best path forward. If the two agencies can’t agree, the state retains the authority to take an enforcement action and require specific actions to address the leak, Ecology said in its release.
