“Deeply worrying”: Federal authorities suspect that radioactive waste is leaking into the ground from World War II tanks in Washington

Annette Cary / Tri-City Herald (TNS)

A third aging underground tank at the Hanford nuclear site is suspected of leaking highly radioactive and hazardous chemical waste into the ground, the Energy Department said Thursday.

“This is of great concern to the Washington State Department of Environmental Quality and must be addressed urgently,” said Laura Watson, director of environmental affairs, in a statement. The state agency is a regulator of Hanford.

Since the storage of radioactive waste in underground tanks at Hanford in Eastern Washington began during World War II, it is suspected that at least 68 of the site's 149 single-shell tanks have leaked waste or leaked into the ground.

However, after removing as much liquid waste as possible from the tanks, only two tanks were known to leak, at least to a detectable extent.

None of those tanks have been emptied yet, although the Energy Department entered into an agreement with Ecology two years ago to explore ways to speed up the timeline for recovering waste from the two tanks that were then known to be leaking.

The agreed order also called for the development of a response plan for future spills. However, that plan is not yet finalized, and DOE and Ecology will discuss next steps for the most recent tank of concern, Tank T-101.

Watson said the state does not believe “this tank poses an immediate danger to workers or the public.”

Estimates of waste leakage

Tank T-101 is part of a group of 16 underground tanks known as the T Tank Farm. Tank T-111 was found to be leaking waste into the ground, the Energy Department said in 2013. Then in 2021, it was reported that tank B-109 in the B Tank Farm was also leaking.

Tank T-101 is one of the smaller waste storage tanks at Hanford, with a capacity of 530,000 gallons. Some single-hull tanks have a capacity of 1 million gallons.

It was built between 1943 and 1944 and has contained waste since 1945. More waste was added until 1979. It currently holds about 93,000 gallons of waste, most of which is sludge and salt cake.

However, it also contains an estimated 7,000 gallons of liquid waste that could not be removed during the Department of Energy's campaign to pump liquid waste from all single-wall tanks to prevent leaks. In 1993, as much liquid waste as possible was removed from Tank T-101.

According to estimates by the Ministry of Energy, the tank could now lose up to 750 litres per year.

For comparison, the Department of Energy estimates that Tank T-111 loses between 150 and 300 gallons per year, and Tank B-109 loses about 3.5 gallons per day, or annually.

Groundwater lies about 180 feet beneath the T Tank Farm, and official estimates suggest that the leak from Tank T-111 could reach groundwater moving toward the Columbia River in a few decades.

Hanford's single-wall tanks and 27 newer double-wall tanks hold 56 million gallons of waste from chemical processing of irradiated uranium at the 580-square-mile nuclear reservation near Richland. The goal is to recover nearly two-thirds of the plutonium used in the nation's nuclear weapons program from World War II through the Cold War.

Waste from single-walled tanks will be emptied into the limited space of newer double-walled tanks and stored there until it can be processed for disposal. The Hanford vitrification plant is scheduled to convert some of the least radioactive waste in the tanks into a stable glass form starting in August 2025.

Tank T-101 was not on the list of suspected leaking tanks when irregularities were discovered during ongoing monitoring of tank integrity and availability by DOE contractor Washington River Protection Solutions.

A camera inserted into a riser pipe, a tube that runs from the ground into the enclosed tank, showed that the accumulation of liquid waste above the waste in the tank appeared to be smaller than usual. This prompted a more thorough analysis of the data, including checking for liquid trapped in pockets within the solid waste.

The Energy Department's tank farm contractor concluded that the tank was “most likely” leaking, Energy Department spokesman Ed Dawson said.

Plans for radioactive waste

“The total volume of waste is relatively small, and the waste is seeping into a large underground area that is contaminated by previous discharges of millions of gallons of waste into soil disposal sites and leaks from multiple tanks,” the Energy Department said in a message to Hanford employees Thursday morning.

The Department of Energy maintains a state-of-the-art groundwater treatment facility, the 200 West Groundwater Pump and Treat System, that removes certain types of chemical and radioactive contaminants from groundwater in the T Tank Farm area.

In addition, following the discovery of the leak in tank B-109, the Department of Energy is required to build a surface barrier over the T and B tank farms to capture rain and melting snow and prevent contaminants from moving deeper into the soil and toward groundwater. This is part of the agreement reached following the discovery of the leak in tank B-109.

Some of T Farm's tanks were already covered with a barrier, but it did not extend to the newest affected tank, Tank T-101. Both barriers must be completed by 2028. Design work is currently underway for the T Tank Farm barrier.

The latest tank suspected of leaking “is another indication of the growing threat that the aging and dilapidated infrastructure at the Hanford site poses to Washington's environment and surrounding communities,” Watson said.

She said it was critical for the Energy Department to get the waste out of the tanks as quickly as possible, put it into an immobile, solid form and dispose of it permanently before more tanks leak.

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