The Japanese government is to fund a costly, untested subterranean ice wall in a desperate step to stop leaks of radioactive water from the crippled Fukushima nuclear plant after repeated failures by the plant's operator.
The dramatic move comes just days before the International Olympic Committee chooses a host city for the 2020 Olympics from Tokyo, Istanbul and Madrid.
The Fukushima plant has been leaking hundreds of tonnes of contaminated underground water into the sea since the 2011 earthquake and tsunami. Several leaks from tanks storing tainted water in recent weeks have heightened the sense of crisis that the utility's owner Tokyo Electric Power (Tepco) is unable to contain the problem.
"Instead of leaving this up to Tepco, the government will step forward and take charge," Prime Minister Shinzo Abe said. "The world is watching if we can properly handle the contaminated water but also the entire decommissioning of the plant."
The government plans to spend an estimated 47 billion yen (HK$3.68 billion) by the end of next year on two projects - the ice wall and upgraded water treatment units supposed to remove all radioactive elements but tritium - according to energy agency official Tatsuya Shinkawa.
The government is not paying for urgently needed water tanks and other equipment that Tepco is using to stop leaks.
The ice wall would freeze the ground to a depth of up to 30 metres through a system of thin pipes carrying a coolant as cold as minus 40 degrees Celsius. It would thus stop contaminated water escaping the facility's immediate surroundings, as well as keep underground water from entering the reactor and turbine buildings, where most contaminated radioactive water has collected. The project, which Tepco and the government proposed in May, is set for completion by March 2015.
Similar methods have been used to keep water from parts of tunnels and subways, but building a wall that surrounds four reactor buildings and their related facilities is unprecedented. The wall could cost 30 billion to 40 billion yen for initial installation, plus an annual running and maintenance cost.
Tepco has been pumping water into the wrecked reactors to keep cool nuclear fuel that melted when the March 2011 earthquake and tsunami knocked out the plant's power and cooling system. Tepco has built more than 1,000 tanks holding 335,000 tonnes of contaminated water at the plant, and the amount grows by 400 tonnes daily.
Tepco is also constructing an offshore wall of steel panels along the coast to keep contaminants from spreading further into the sea. The utility company said radioactive elements had mostly remained near the embankment inside the bay, but experts reported offshore "hot spots" of sediments contaminated with high levels of caesium.
The leaks came as Tokyo headed into the final days of the contest to host the 2020 Olympics. With demonstrations against the Turkish government plaguing Istanbul's bid, and a recession and high Spanish unemployment hanging over Madrid's candidacy, Tokyo is pushing itself as the safe choice in uncertain times. The IOC will select the 2020 host on Saturday in Buenos Aires, Argentina.