Frozen soil would act as a barrier to prevent fresh groundwater from running beneath the buildings and picking up radioactive particles.
A total of 1,568 pipes have been dug into the ground. They will carry a refrigerant liquid chilled to minus 30 degrees Celsius. The government and Tepco hope to switch on the barriers by the end of March.
Currently, 450 tons of water are becoming tainted every day — a volume that must be pumped out, stored and filtered.
Tepco believes that the ice shield will reduce the flow significantly, bringing the daily total down to 150 tons. It began installation work in June 2014.
The success of the project is not assured. The Nuclear Regulation Authority is monitoring it closely as the shields may lower the level of groundwater around the reactor buildings, potentially triggering a release of contaminated water that is currently sitting in the buildings’ basements.
Read more at Tepco finishes installing Fukushima ice shield equipment