Last part of Fukushima ice wall being frozen

The final part of an ice wall surrounding the damaged Fukushima Daiichi reactors is being frozen, Tokyo Electric Power Company (Tepco) said yesterday. The ice wall prevents the travel of water into or out of the reactor building basements.

The wall has been in preparation for over three years to address the issues that arise when groundwater naturally flows from land to sea, passing through the Fukushima Daiichi site. It is normal for groundwater to get into building basements through small cracks and openings, and it usually simply pumped out again. However, at Fukushima Daiichi the building basements contain large amounts of highly contaminated water that has been used to cool the remains of the reactor cores. It is therefore important for Tepco to prevent groundwater entering the basements and adding to the volumes there, and also to prevent contaminated basement water leaking out.

The ice wall has been frozen in sections as permissions have been granted by the Nuclear Regulation Authority since March 2016. This week, permission was granted for the final seven meter section and Tepco began freezing it yesterday. Similar technology is widely used in the construction industry, but Tepco's implementation is the largest to date, freezing 70,000 cubic meters of soil along its 1500 meter path around units 1-4.

A cross section of the ice wall, or Land-side Impermeable Wall, as it is officially known (Image: Tepco)

Tepco said it will measure the success of the wall in contolling water flows by checking the differences between water levels inside and outside the wall, and inside and outside the buildings.

Researched and written
by World Nuclear News