Dec 21 (Reuters) - The operator of Japan's crippled Fukushima nuclear power plant intends to build an underwater tunnel to release water from the plant into the sea, it said on Tuesday, as part of a project to treat and dispose of contaminated water.
A decade after a massive earthquake and tsunami ravaged the northeastern coast, disabling the plant and causing the world's worst nuclear disaster since Chernobyl, nearly 1.3 million tonnes of contaminated water has accumulated at the site.
The water, enough to fill about 500 Olympic-sized swimming pools, is stored in huge tanks at an annual cost of about 100 billion yen ($880 million), and space is running out.
This year, Tokyo Electric Power (9501.T) (Tepco) outlined plans to discharge more than 1 million tonnes of the water, after treatment and dilution, from a point about 1 km (0.6 miles) offshore from the power station.
Tepco submitted detailed plans on Tuesday to the nuclear regulation authority for approval, Junichi Matsumoto, a company official, told reporters.
Pumps would move the treated water from the tanks to the seashore and through a seabed tunnel to release it at a depth of 12 metres (40 ft), and about 1 km out at sea, the firm said.
