TOKYO—The operator of Japan’s destroyed Fukushima nuclear plant switched on a giant refrigeration system on Thursday to create an unprecedented underground ice wall around its damaged reactors. Radioactive water has been flowing from the reactors, and other methods have failed to fully control it. The decontamination and decommissioning of the plant, damaged by a massive earthquake and tsunami in 2011, hinge of the success of the wall.
Q. WHAT IS AN ICE WALL?
A. Engineers installed 1,550 underground refrigeration pipes designed to create a 1.5-kilometer (0.9-mile) barrier of frozen soil around four damaged reactor buildings and their turbines to control groundwater flowing into the area and prevent radioactive water from seeping out. The pipes are 30 meters (100 feet) deep, the equivalent of a 10-story building. Engineers say coolant in the pipes will freeze the surrounding soil to minus 30 degrees Celsius (minus 22 Fahrenheit), creating the wall over several months.
