Work starts on Fukushima ice wall

03 June 2014

On June 2, the operator of Japan's crippled Fukushima nuclear plant began work on a substantial underground ice wall to contain leaking radioactive water from the damaged reactors. The 1.4km-long wall will be made by inserting 1,550 pipes into the ground which will later be filled with coolant that should freeze the surrounding soil.

The Fukushima ice wall will be 1,400m long

In late May, Japan’s Nuclear Regulation Authority agreed that plant operator Tokyo Electric Power Company (Tepco) could begin construction work on the frozen wall. The pipes should be in place by March 2015, after which the coolant should be inserted into the pipes with the wall fully frozen and operational nine months later.

The construction of the ice wall is estimated to cost some ¥32 billion ($313 million)and will be paid for by the Japanese government.

The ice wall will enclose the plant on four sides, stopping groundwater from seeping into the plant and mixing with contaminated water inside, as well as stopping the contaminated water from leaking into the sea.

The plant has experienced several leaks of radioactive water since being crippled by an earthquake and tsunami in 2011, which resulted in three of the plant’s nuclear plant's reactors melting down.

Water is now being pumped in to cool the reactors, but storing the resultant large quantities of radioactive water has proved a challenge for Tepco. The operator has also struggled to safely store groundwater that has mixed with the radioactive water and become contaminated.

Last month, Tepco began releasing groundwater into the sea after checking its radiation levels.

Ice wall technology is already widely used in civil engineering projects, such as the construction of tunnels near waterways. Small-scale tests using the technology have already been completed at the Fukushima site but the full-scale use of the technology there will be the largest ground freezing operation in the world.

Keeping the ground frozen in an area with summer temperatures close to 40C may be difficult, some experts say.