Une barrière de glace pour stopper les fuites d'eau radioactive à Fukushima

En septembre, le gouvernement japonais a donné son accord sur un projet de création d'une barrière de permafrost artificiel de 1,6 km de long autour de la centrale nucléaire de Fukushima afin d'empêcher la propagation d'eau radioactive. (en anglais)
In early September, Japan’s government gave the go ahead on a project to create a mile-long artificial permafrost barrier around the Fukushima power station to stop radioactive water from leaking.

Every day approximately 400 tons of groundwater flowing down from the nearby mountains, enters cracks in the reactor buildings damaged by the meltdowns and explosions at Fukushima in 2011. It then pollutes the ground water downstream and ultimately spills into the sea, according to an April 2013 Tepco briefing document.
Responses so far have been ineffective, consisting in pumping contaminated groundwater into holding tanks, adding to over 300 000 tons of radioactive water already stored at Fukushima.

The USD 473 million project requires burying refrigeration pipes to a depth of 100 feet, approximately every yard for almost a mile around the site. The pipes would freeze the ground to keep water flowing in and out, thanks to brine or another type of ice slurry, cooled down to temperatures from -20 to -40°C. 
Theoretically there are other ways to seal off the site from groundwater, digging huge trenches and filling them with clay or concrete, is one example, but ice has a self-healing quality which represents a big plus. It could also last for months in the event of an electricity cut.

An ice barrier was already used at Oak Ridge National Laboratory in Tennessee, but the Fukushima project is 150 times bigger and ironically, will require enormous amounts of energy, until the plant is successfully dismantled.