Ice wall at Fukushima plant switched on, but will it work?

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 cooling water becomes radioactive and leaks out through damaged areas into the building basements, where it mixes with groundwater, increasing the volume of contaminated water.

Nearly 800,000 tons of radioactive water have been pumped out, treated and stored in 1,000 tanks that now occupy virtually every corner of the Fukushima plant, interfering with its decontamination and decommissioning and adding to the risk of further leaks of water into the nearby ocean.

Experts are also concerned that an ice wall cannot be adjusted quickly in an emergency situation, such as a sudden increase in the flow of contaminated water, because it takes several weeks to freeze or melt.