NRA, Tepco agree to start frozen underground wall at Fukushima No. 1 in stages


The Nuclear Regulation Authority and Tokyo Electric Power Co. have broadly agreed to start operating the frozen underground wall at the Fukushima No. 1 nuclear plant in stages.

The agreement, reached Monday, is on the frozen underground wall that officials hope will surround the buildings housing reactors 1 through 4 and reduce the amount of groundwater flowing into the facilities.

The buildup of water contaminated with radioactive materials in the reactor building basements has been a major complication at the plant since it was heavily damaged in the March 2011 earthquake and tsunami.

Tepco has accepted an NRA request to start out slow by operating the frozen wall in a limited area. The NRA is concerned that the wall may lower groundwater levels around the reactor buildings too much and lead to tainted water flowing back out of the reactor buildings.

It is uncertain, however, how effective the wall will be in curbing the inflow of groundwater if its operation is limited.

The amount of contaminated water at Fukushima No. 1 continues to rise due to the groundwater flowing into the reactor buildings. As of Thursday, the amount of tainted water kept in storage tanks stood at nearly 800,000 tons, with the amount increasing by several hundred tons per day.

The Ministry of Economy, Trade and Industry and Tepco have been seeking approval from the NRA to start up the frozen wall for its entire 1.5-km length.