The head of the Department of Energy’s Office of Environmental Management, Tim Walsh, recently wrote the director of Washington state’s Department of Ecology to stress “the urgency” DOE places on state approval of grouting some of Hanford Site’s less-radioactive waste.
DOE appreciates Washington state’s “willingness to consider our proposed ‘glass-plus-grout’ strategy” for the 200 East Area at Hanford, Walsh said in the June 26 letter to Washington Ecology Director Casey Sixkiller.
“It is apparent that we did not convey the urgency of the permit requirement to allow grouting of excess treated liquid in Tank AP-106,” DOE’s assistant secretary for environmental management (EM-1) wrote to Sixkiller.
“I would like to meet with you at your earliest convenience,” to discuss the situation, Walsh said. Today AP-106, which is one of the Hanford Site’s eight double-shell tanks at the AP Tank Farm, is 96% full of pre-treated waste.
““Every month that we wait to start grouting, liquid waste in single-shell tanks poses a hazard to people and the environment,” Walsh went on to say.
The Walsh letter comes about a month after Sixkiller wrote DOE saying he was not opposed to grout but wants the focus to stay on converting Hanford’s liquid radioactive tank waste into a glass form at the multi-billion-dollar Waste Treatment Plant.
“This letter does not change the concerns we shared from our initial letter to Energy on May 22,” an Ecology spokesperson said in a late Wednesday email reply to Exchange Monitor. “We have not received a permit modification request on this new initiative. It’s highly unusual that Energy is publishing opinion pieces and pushing for approval on a new initiative they haven’t yet sent our agency a detailed plan or permit application for.”
The Ecology statement referred to DOE’s desire to “divert” pretreated waste away from the Waste Treatment Plant and grout it instead. The state agency spokesperson declined comment on the status of any planned meetings.
Walsh said the glass-making plant cannot yet keep up with the need.
The supply of pre-treated waste can either be “vitrified” — or converted into a solid-glass form at the Direct-Feed-Low-Activity Waste Facilities (DFLAW) at Hanford’s Waste Treatment Plant — or it could be “grouted and shipped out of state for disposal” Walsh said in the June letter.
“Unfortunately, DFLAW is still going through startup issues and cannot keep up with vitrifying the available pre-treated waste stream from AP-106,” Walsh said in the letter. It might take another 12-to-18 months before DFLAW is fully operational, said the Environmental Management boss.
DOE uses the Tank Side Cesium Removal (TSCR) project to extract most of the cesium and strontium from the waste that comes out of old single-shell underground tanks, some of which have leaked in the past. The pre-treated waste goes into AP-106 prior to solidification.
But the TSCR throughput is roughly 100,000 gallons per month while the DLFAW is currently only solidifying 20,000 gallons per month, Walsh wrote. DOE recently surpassed solidification of 115,000 gallons of the less radioactive waste since DFLAW started operations in October 2025. “DOE is not satisfied with the pace of progress,” Walsh said.
As of February 2026, 1.2 million gallons of tank waste had been pre-treated via the TSRC system, Walsh wrote. So, unless DOE can soon start grouting some of the waste, DFLAW will not be able to keep up with the pretreated waste that is being created and as a result the emptying of old single-shell tanks could slow to a crawl.
By the end of 2027, DOE plans to replace TSCR with a larger-scale pre-treatment setup, the Advanced Modular Prestreatment System. Once the new, bigger system goes online, the pretreated waste capacity will outstrip DFLAW’S designed capacity by 130,000 gallons monthly, Walsh said.