HANFORD TANK CLEANUP UPDATE MAY 2009 [VISIT US AT WWW.WRPSTOC.COM OR WWW.HANFORD.GOV/ORP/ FOR MORE INFORMATION]

Retrieval of waste from single-shell tank C-110 resumed in January making it the first waste retrieval operation for WRPS since taking over Hanford's Tank Operations Contract last October. Now, with approximately 90 percent of the waste removed, WRPS believes that modified sluicing has reached the limits of the technology to remove any further waste and is preparing documentation for use in decision making about any future retrieval actions. Tank C-110 is located in C Fann near the center of the Hanford Site. It is a 530,000 gallon tank, built in 1946, and held approximately 126,000 gallons of sludge and other radioactive and chemical waste materials when retrieval resumed. Modified sluicing technology uses liquid waste from a nearby double-shell tank to break up, dissolve and mobilize the solid material so it can be pumped. Because of the variety of waste fon11S, sluicing is often not able to remove all of the waste. The remaining waste will next be sampled for analysis, and results will be used to guide decisions regarding future actions. Work is moving rapidly in preparation to retrieve waste from a second single-shell tank this summer and transfer it to safer double-shell tank storage. Construction activities necessary to retrieve waste from Tank C-104, a 530,000 gallon tank built in 1943, are approximately 60 percent complete as WRPS maintains its focus on reducing the risk posed by Hanford's aging single-shell waste tanks. C-104 is one of Hanford's oldest radioactive and chemical waste storage tanks, containing approximately 263,000 gallons of wet sludge with a top layer that is dry and powdery. This will be the largest sludge volume retrieval ever attempted using modified sluicing technology. Modified sluicing uses high pressure water or liquid radioactive waste sprayed from nozzles above the waste. The liquid dissolves and/or mobilizes the waste so it can be pumped. In addition to other challenges, tank C-104 contains a significant amount of plutonium and uranium. It also contains a host of contaminated legacy equipment so the entire process is being managed carefully to protect workers and the environment