A demonstration site of an underground frozen wall to block radioactive water leak from Fukushima No.1 Nuclear Power Plant was revealed to the press on May 22. The test has been performed to identify the detailed construction method and to confirm the capability of the wall. The plan to build a 1500m long ice wall around the plant will be undertaken within June once permitted by the Nuclear Regulation Authority.

The project will place steel pipes underground with coolant inside to freeze the earth. Frozen walls are usually adopted to stop water leaking at construction such as undersea and tunneling. The experiment, started last August by Tokyo Electric Power Co. and Kajima Corp., is one of Economic Ministry’s measures against contaminated water leaking. The experiment tested effectiveness of a miniature wall of 10m long.

The project is believed to be the largest of the kind in Japan, according to Kajima’s official. The total cost is estimated at 32 billion yen. Completion is due in summer 2015 and the soil will be kept frozen for next 7 years. (2014/05/19)