Hanford Site contractor Washington River Protection Solutions (WRPS) expects in October to resume removal of waste from a leaky tank at the former Department of Energy plutonium production facility.
The tank farm manager has removed all but the bottom layer of 750,000 gallons of chemical and radioactive waste once held in double-shell Tank AY-102. Roughly 41,000 gallons of sludge remains to be extracted.
Removal stopped in April to allow workers to place four extended-reach sluicers into the tanks — essentially “water cannons” used to break up the remaining waste so it can be pumped out, WRPS spokesman John Britton said by telephone Monday. The fourth sluicer was installed in July, according to a site report from the Defense Nuclear Facilities Safety Board. The hose, electrical, and control-cable links are still being completed, according to Britton.
The contractor has until March 4, 2017, to complete the project, under a settlement agreement with Washington state. “We’re on schedule to meet that deadline,” Britton said.
Waste removal began in March of this year, and all liquid material — about 600,000 gallons — has been pumped to other double-shell waste tanks on site, along with about 112,000 gallons of sludge.
The project has faced a number of challenges, including an increase in the amount of waste leaking into the space between the shells — the annulus. That leak was the cause of the waste removal in the first place, but spiked significantly in mid-April during pumping operations, with the waste level in the annulus topping out at about 8.4 inches.
“During last Spring’s sludge retrieval about 3,000 gallons of waste entered the annulus due to sluicing efforts opening up a less-restricted pathway from the primary tank to the annulus,” Britton said by email Tuesday. “The majority of the waste was pumped from the annulus back into the primary tank. We continue to monitor the annulus and have a contingency plan in place to pump the annulus as necessary. ”
Once operations resume, they must adhere to restrictions on tank farm activities established after more than 50 workers in recent months reported possible exposure to vapors from the waste containers. The Department of Energy and WRPS have pledged to take a number of steps to protect workers in the tank farms, with some of those measures also subsequently required under a federal court order. These include only conducting operations that disturb tank waste, including waste removal from Tank AY-102, if safety reasons make the work necessary.
Washington state, the nongovernmental Hanford Challenge, and Plumbers and Steamfitters Local Union 598 have requested a preliminary injunction requiring further safety steps, and a hearing is scheduled in federal court in Spokane on Oct. 12. The outcome of that hearing will “dictate a lot of our preparations,” Britton said.
The project’s cost was not immediately available.
