Checking icewall's effectiveness

November 2, 2016

Ice wall at Fukushima plant to be examined

http://www3.nhk.or.jp/nhkworld/en/news/20161102_27/

Japanese government officials and the operator of the crippled Fukushima Daiichi nuclear plant say they plan to dig and check the ground around reactors. They want to see if an ice wall installed there is working as intended.

The underground ice wall is meant to prevent groundwater from getting into the damaged reactor buildings and becoming contaminated.

Tokyo Electric Power Company has been creating a 1.5 kilometer-long barrier of frozen earth since March. The ice wall is formed by circulating coolant in pipes buried around the reactor site.

Engineers believe that except for an area on the plant's hillside, the freezing work has been completed.

Government and TEPCO officials have relied on thermometers in the ground to determine if the soil is frozen. But Japan's nuclear regulator has urged them to more precisely check the conditions underground and the ice wall's effectiveness.

This month, workers will dig several meters into the ground south of the Number 4 reactor to directly check the condition of the frozen wall. The area was chosen due to its relatively low radiation level.

Later this month, officials from a government task-force will inspect the site.

TEPCO's decommissioning roadmap calls for most of the contaminated water to be removed from the reactor buildings in 2018. To achieve this, the ice wall needs to be completed and effectively preventing groundwater from flowing into the reactor buildings.