June 2, 2016

TEPCO examines ice wall at Fukushima Daiichi

http://www3.nhk.or.jp/nhkworld/en/news/20160602_28/

The operator of Fukushima Daiichi nuclear power plant will conduct extra work to help freeze the ground around the buildings housing the 4 crippled reactors.

Tokyo Electric Power Company discussed the idea with officials of the Nuclear Regulation Authority on Thursday.

TEPCO made the proposal after reporting some problems with a 1.5-kilometer-long frozen soil wall it has been building around the 4 reactor buildings since March.

The wall is aimed at cutting the amount of groundwater flowing into the basement of the buildings, where it becomes contaminated with radioactive substances and can flow out of the plant in the direction of the sea.

TEPCO said the amount of groundwater in some areas outside the wall near the sea has not yet fallen.

TEPCO said rainfall may be partly to blame for the problem, and added that it has seen a drop in groundwater levels elsewhere, in areas much closer to where the wall has been completed successfully. TEPCO said that, overall, the wall appears to be proving effective.

But many members of the regulatory agency said TEPCO's argument is not convincing enough.

TEPCO admitted that underground temperatures at several locations along the wall have not yet fallen to zero, which indicates that the ground is not frozen there.

TEPCO said it will start extra work to pour cement into those locations to help seal off the wall completely.

The utility said it will be about a month before it can determine if the extra work has started producing a positive effect in reducing the amount of groundwater flowing in.