The Department of Energy will not immediately begin emptying radioactive and hazardous chemical waste from two underground tanks that are leaking waste into the ground at the Hanford nuclear reservation.

Instead, it will take steps to limit the spread of the waste and consider ways to revise its tank waste retrieval schedule to possibly empty the waste from the two tanks sooner.

It also will develop Hanford’s first comprehensive plan for responding to future leaks from Hanford’s 149 single-shell tanks, which are prone to leaking.

The actions were agreed on after more than a year’s negotiation with the Washington state Department of Ecology, a Hanford regulator, after the second of the two leaks, from Tank B-109, was discovered.

“We worked really hard with the U.S. Department of Energy to ensure we developed the best and most feasible protective measures for the B-109 leak, while also ensuring Energy develops a contingency plan when future leaks occur,” said Ryan Miller, communications manager for the Nuclear Waste Program at the Department of Ecology.

“Our agency believes the suite of near-term and long-term actions required by this order is the best approach for addressing these leaks and future single-shell tank leaks, given the existing lack of infrastructure, technology and funding available,” he said.

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Two Hanford tanks leaking

DOE announced in 2013 that single shell Tank T-111, which holds about 397,000 gallons of waste, was leaking.

Then in spring 2021 it said a second tank, B-109, which holds about 123,000 gallons of radioactive waste, also was leaking and at a rate faster than Tank T-111.

Tank B-109 is estimated to be leaking about 560 gallons of waste per year, and Tank T-111 is estimated to be leaking about 300 gallons per year.

In the past, as many as 67 single-shell tanks were suspected of leaking or spilling waste into the ground at the nuclear reservation in Central Washington near Richland.

But work from the 1990s to about 2005 to empty the site’s single-shell tanks of as much liquid waste as possible, leaving sludge and salt cake, helped reduce the risk of leaks.

Waste retrieved from the tanks is moved to 27 newer double-shell tanks for storage until it can be treated.

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DOE expects to begin treating some of the least radioactive of the tank waste to allow permanent disposal at the end of 2023.

The waste is left from the past production of plutonium from World War II through the Cold War for the nation’s nuclear weapons program. Some of the tanks, including B-109, have held waste since World War II.

Neither of the two single-shell tanks known to be leaking are near double-shell tanks, and will require extensive infrastructure not only to empty waste from the tanks but to move it to double-shell tanks.

DOE said last year that Tank B-109 is about 2 miles from the nearest double-shell tank and building the piping and infrastructure to move it would cost hundreds of millions of dollars

Both leaking tanks also are in areas where waste contaminated with liquid was disposed of in the soil during Hanford’s production years. Already contaminated groundwater in central Hanford is being pumped up and treated to remove contamination that would otherwise move through the ground toward the Columbia River.

The waste leaking from B-109 could take up to 25 years to reach groundwater and the waste from T-111 could take up to 70 years, by some estimates.

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Protecting groundwater

The viability of installing a ventilation system to evaporate liquid waste in Tank B-109 will be evaluated. A ventilation system was previously used in Tank T-111 to help dry it out.

The evaluation by DOE is due in August 2023.

The next protective action that could be completed under the agreement between the state and federal government would be building a barrier over the ground above both leaking tanks to keep rain and snow melt from reaching the tanks and to slow the movement of leaked waste toward groundwater.

The barriers will be completed in 2028, under a schedule worked out by DOE and the state. DOE previously has installed four of the barriers over other groups of underground tanks.

Both tanks also will be evaluated to see if additional work can be done to keep liquids from infiltrating the tanks.

Consideration of whether retrieval of the waste from the two tanks could be moved up in the schedule of work at Hanford’s tank farms would be considered as the site completes its next comprehensive look at tank waste plans in 2023. The work is done every three years.

The comprehensive plan for addressing further waste leaks in Hanford’s underground tanks is due in one year.

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It must include options for retrieving as much of the waste as necessary to stop leaks, as well as shorter term options such as ventilation, and must include a process to determine the best action on a tank-by-tank basis.

“It’s been a priority for the state of Washington to address leaking tanks in a way that protects nearby communities and the Columbia River,” said state Ecology Director Laura Watson. “We know that ongoing vigilance and commitment will be needed to fully address these risks, but I appreciate the work put in by both teams to agree on a plan that prioritizes safety and environmental protection.”

The waste leaking from B-109 does not appear to threaten the health of people in the near term, said Gov. Jay Inslee when the leak was announced last year and the state and DOE started talks on what action to take.

The state Department of Ecology has the legal authority under the Tri-Party Agreement to take immediate action in response to the leaking tank only if it is “necessary to abate an imminent and substantial endangerment” to people or the environment, according to state officials.

“I appreciate the effective collaboration with the Ecology team in reaching an agreement that supports our continued focus on safe, efficient and effective stewardship, treatment, and disposition of tank waste,” said Brian Vance, DOE Hanford manager, as the agreement between DOE and the state was signed Thursday.