Science / Medicine : New Plan to Ice Hazardous Wastes

An engineering company and the University of Washington unveiled a detailed plan last week to safely contain underground radioactive wastes with giant, canoe-shaped refrigerators. Concept RKK Ltd. of Bellevue, Wash., proposes to build ice walls 50 to 75 feet thick using frozen, sunken pipes that would halt the migration of chemical and radioactive waste leaking from underground storage tanks.

Millions of gallons of such waste have leaked or are in danger of leaking from the Hanford Nuclear Reservation in eastern Washington over springs that feed the Columbia River above Portland, Ore.

The walls are made by sinking several pipes a few feet apart around a polluted area, inserted at a slant to form the boat-shaped rib cage around the polluted ground. A second layer of pipes mirroring the first is installed about 30 feet away. The depth depends on how far hazardous wastes have advanced toward ground water.

Refrigerant pumped into the pipes causes water around them to freeze solid, forming thick ice walls within six months to a year.