The battle to keep the earthquake-damaged Fukushima nuclear plant in Japan from threatening the environment just entered an icy new phase.

Last week, Tokyo Electric Power Co. (TEPCO), the company that owns the plant, received permission from the Japanese government to activate a process that will generate a massive subterranean ice wall around the plant. The unprecedented scale of the $300 million project is something of a last-ditch effort to stop the release of contaminated wastewater into the sea.

“We will create an impermeable barrier by freezing the soil itself all the way down to the bedrock that exists below the plant,” TEPCO said in a statement. “When groundwater flowing downhill reaches this frozen barrier, it will flow around the reactor buildings, reaching the sea just as it always has, but without contacting the contaminated water within the reactor buildings.”

To create an impermeable barrier of frozen soil, TEPCO installed massive vertical refrigeration pipes 100 feet into the ground in a wall spanning nearly a mile around the reactors and turbine buildings. As the earth around the plant freezes down to -22 Fahrenheit, it's hoped that the more than 400 tons of groundwater currently entering the reactor's contaminated basement will cease altogether.

In the late '90s, a U.S. Department of Energy laboratory used this same technique on a much smaller scale to isolate radioactive waste entering groundwater in Tennessee. Whereas that particular cleanup took six years, Fukushima is expected to last decades. It's unknown if the solution will prove successful over that length of time.

“It would be best to think that natural phenomena don’t work the way you would expect,” Shunichi Tanaka, chairman of the Nuclear Regulation Authority, told reporters this past week.

Nearly 800,000 tons of radioactive wastewater is stored at the site, with an unknown amount having leaked into the ground after the 2011 disaster. Last December, the Woods Hole Oceanographic Institution reported record-breaking, but not yet life-threatening, levels of Fukushima radiation in waters along the U.S. West Coast.