Hanford starts emptying radioactive waste from a leak-prone tank. First in 17 months

Hanford workers have begun retrieving radioactive waste from another of the nuclear reservation’s 149 leak-prone underground waste tanks.

To date the Department of Energy has completed waste retrieval from 17 of its 149 single shell tanks, some of them built in the 1940s. At least one of the 132 tanks yet to be emptied is leaking waste into the ground below.

DOE has been working to empty the tanks of their solid waste — thick sludge and salt cake — for about 22 years, moving waste from single shell tanks into 27 newer double shell tanks for storage until the tank can be treated for disposal.

As work starts to empty Tank AX-104, it is the first time that DOE contractor Washington River Protection Solutions has started emptying waste from a tank since August 2019.

“We are happy that Energy undertook this effort, especially given the additional challenges posed by the pandemic,” said Jeff Lyon, tank waste storage project manager for the Washington state Department of Ecology, the regulator on the project.

The start of work on Tank AX-104 comes after the recent announcement that Washington River Protection Solutions will stay on longer as the Hanford tank farm contractor.

Work shifted to the AX Tank Farm after the 16 tanks of the C Tank Farm were emptied to meet standards set by the Tri-Party Agreement. The 17th tank emptied was in the S Tank Farm.

After completing the C Tank Farm, DOE paused work to install retrieval infrastructure for the next group of tanks it planned to retrieve, believing that would be faster than the past strategy of installing retrieval infrastructure tank by tank.

Tank deadline

The federal court set a deadline to have two more tanks emptied by the end of June, but the court is allowing at least eight more months to meet that deadline because of work delays to prevent the spread of COVID-19.

Along with the AX tank where retrieval began in 2019, emptying Tank AX-104 would meet the deadline. Work has halted on the first AX Tank where retrieval has started — Tank AX-102 — while a determination is made by DOE and its regulators about whether enough waste has been retrieved or work needs to continue.

“For all retrieval projects, we develop a thorough project plan, choose the right tools for the job and complete work safely,” said Doug Greenwell, retrievals manager for the tank farm contractor.

Workers will use a technology called the enhanced reach sluicing system, inserting it through risers — the narrow vertical pipes that allow access from above ground to the enclosed underground tanks.

Three cannon-like sluicers, a central pump and six camera and lighting systems were lowered into the tank.

The sluicers were extended in the tank, allowing nozzles to spray liquid as close as possible to the waste. The liquid is used to break up the waste and move it toward a pump for removal.

Tank AX-104, one of the four tanks in the AX Tank Farm, has a capacity of 1 million gallons, but contains far less waste. Pumpable liquids were removed more than a decade ago in a campaign to make all of the single shell tanks less likely to leak.

It is not one of the Hanford tanks that is suspected of leaking in the past.

Tank AX-104 now has more than 5,000 gallons of radioactive waste on on its floor and another 2,000 gallons of sludge clinging to its walls.

‘Helps reduce risk’

Workers set the stage for retrieval of Tank AX-104 by carefully removing obsolete and highly contaminated pumps and equipment to measure the temperature of the waste.

Infrastructure that was added to retrieve waste from Tank AX-104 and other nearby tanks include a new ventilation system to filter emissions and a building for the water supply systems used to support retrieval activities.

The Hanford nuclear reservation in Eastern Washington has 56 million gallons of radioactive and other hazardous chemical waste stored in underground tanks. It remains from the production of plutonium during World War II and the Cold War for the nation’s nuclear weapons program.

“Moving waste into the double-shell tank system helps reduce risk to the environment and allows for safe storage of the waste until it can be treated,” said Brian Harkins, DOE deputy assistant manager for tank farms.

Much of the waste is planned to be turned into a stable glass form at the Hanford site’s $17 billion vitrification plant starting as soon as the end of 2023.

Washington River Protection Solutions has held the Hanford tank farm contract since 2008 with multiple extensions to its expiring contract, but a new contractor was picked by DOE in May 2020.

However, the award was appealed to the Government Accountability Office, with issues raised that prompted DOE to voluntarily take corrective action.

In late December it announced that Washington River Protection Solutions would stay on as the tank farm contractor as it restarts the bidding process on a new tank farm contract, which will be expanded to include the initial operation of the vitrification plant.