Washington River Protection Solutions workers were able to retrieve another 5,500 gallons of waste from Hanford Tank AY-102 over the weekend, although they had to also pump out waste between its shells several times. WRPS was making good progress in retrieving 151,000 gallons of sludge from the tank because it had a fairly slow leak from its inner shell, until the retrieval operation caused the rate of leakage into the annulus, the space between the tank’s shells, to increase significantly on April 17. As of Monday, an estimated 41,000 gallons of waste remained in the tank. On Monday, waste retrieval was on hold as workers were troubleshooting an issue with the double-shell tank that supplies liquid waste for the sluicing system used to dissolve the sludge and move it toward a pump in the primary shell of Tank AY-102.
The sludge that remains in the primary shell of the tank is no longer in an even layer. It is as deep as 20 to 30 inches near the sides of the tank and less than 6 inches deep in places in the center of the tank. WRPS may need to switch out the sluicing system now being used for retrieval for an enhanced-reach sluicing system that can extend to reach more areas of the tank, despite the quick start to sludge retrieval. The switch in technology was part of the original plan for retrieving waste from the tank, with plans calling for an enhanced-reach sluicing system to be installed in late spring or early summer. Tests continue to show no evidence that any waste has breached the outer tank to reach the environment.
