DOE prepares to resume waste transfer from last single-shell in Hanford’s AX Farm

The Department of Energy this week started creating space in a double-shelled underground waste tank that was nearly full after taking on additional waste from a single-shell tank, an agency spokesperson said.

The Defense Nuclear Facilities Safety Board (DNFSB), in a report published this week and dated April 7, said that DOE’s effort to drain AX-101, the single-shell tank, hit a speed bump because the double-shell tank it was draining into, AZ-102, was “nearly full.”

As a result, the Amentum-led tank management contractor, Washington River Protection Solutions, “paused AX-101 retrieval pending transfer of the accumulated waste from AZ-102” to other double-shell tanks, according to the board document.

On Tuesday May 2 DOE and its contractor started transferring waste to another double-shell tank, AZ-101, from the nearly topped-off AZ-102, a DOE spokesperson wrote Wednesday in an email. 

Three transfers to AZ-101 from AZ-102 should occur before the end of the fiscal year on Sept. 30, according to the recent DNFSB report. , AX-101, the single-shell tank, is “approximately 35% retrieved,” the defense board wrote. Single-shell tanks can be prone to leaks. 

DOE announced in January it is starting to remove about 426,000 gallons of waste from Tank AX-101, using a high-pressure water spray to dislodge saltcake and sludge, and putting it into a newer, safer double-shell tank. Emptying out AX-101 would complete waste retrieval from all four of the 1960s-era single-shell tanks in the AX Farm built to hold waste from Cold War era plutonium production at Hanford.

The waste transfers are meant to reduce health and safety risks surrounding Hanford’s 177 underground tanks until the roughly 56 million gallons can be treated for disposal. The Waste Treatment and Immobilization Plant built by Bechtel should start turning low-level radioactive tank waste into glass by 2025, DOE has said in recent months. That’s about two years later than the agency previously hoped to begin.

The AX-101 retrieval operation has been part of the retrieval plan, and that the plan for a phased retrieval sequence has been known for over a year, DOE said in a Thursday email.