Nearly 800,000 tonnes of contaminated water has been stored in 1,000 huge industrial tanks at the site

Giant ice wall at Fukushima nuclear reactor comes online

A giant, man-made ice wall that has been built underneath Fukushima power plant to create a frozen barrier to contain contaminated water is set to come online tomorrow.

The refrigeration structure, which resembles giant ice lollies, was completed last month but has only just been approved by Japanese regulators.

The decommissioning of the Fukushima reactors has been plagued by a string of radioactive water errors since an earthquake and tsunami hit the plant in 2011.

Radioactive water has reportedly spilled from a drainage system into the ocean on nine separate occasions since January alone.

Nearly 800,000 tonnes of the contaminated water has been stored in 1,000 huge industrial tanks at the site. The vast quantities have been hampering the decontamination process since the 2011 quake and tsunami caused severe damage to the facility.

Although it is hoped the ice wall will help to alleviate these problems, the plan has been delayed for more than a year because of technical uncertainties. Some experts are still sceptical about the technology involved and question whether it is worth the huge costs.

Shunichi Tanaka, the chairman of Japan’s Nuclear Regulation Authority, cautioned against high expectations because the project in part relies on nature. "It would be best to think that the natural phenomenon doesn't work the way you would expect."

The 35bn yen (£218m) government-funded project includes pipes inserted 30m underground that are designed to freeze the soil around them, like giant ice lollies.

They are intended to form a wall just under one mile long around the reactor and turbine buildings in order to contain radioactive water in the area and keep out groundwater.

Similar methods have been used to block water from parts of tunnels and subways, but such a huge structure surrounding four buildings and related facilities is untested. A smaller wall was used to isolate radioactive waste at an US department of energy laboratory in Tennessee, but only for six years.

A test using part of the ice wall has effectively frozen the ground around it, and officials hope that the ice wall will be successfully formed within several months, according to Shinichi Nakakuki, a spokesman for Tokyo Electric Power Company (Tepco) which runs Fukushima.

Tepco officials say they hope the ice wall would effectively cut down the groundwater inflow into the area to about one-eighth of what it used to be and eventually dry up the turbine basements by 2020, confining contamination to the three melted reactors.

Specialised robots that have been created to retrieve radioactive material from the ill-fated power plant have been repeatedly unable to complete their task because the radiation destroys their circuitry when they get close.

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