The ice wall project calls for freezing the soil around the No. 1 to No. 4 reactor buildings that stretches some 1.5 kilometers to a depth of about 30 meters to create a solid barrier by hammering in equidistant cooling pipes and circulating coolant chilled to minus 30 degrees Celsius.The industry ministry on Nov. 21 dug a part of the ice wall to approximately 1.2 meters in depth on the mountain side of the No. 4 reactor building. The soil temperature around the cooling pipes 40 centimeters deep was about minus 10.3 degrees, while an area of 1.5 meters in radius around the cooling pipes was frozen at a depth of 1.2 meters.