TOKYO, Japan — THE Japanese Government yesterday announced that it will spend US$470 million on a subterranean ice wall and other steps in a desperate bid to stop leaks of radioactive water from the crippled Fukushima nuclear plant after repeated failures by the plant’s operator.

The decision is widely seen as an attempt to show that the nuclear accident won’t be a safety concern just days before the International Olympic Committee chooses among Tokyo, Istanbul and Madrid as the host of the 2020 Olympics.

The Fukushima Dai-ichi plant has been leaking hundreds of tons of contaminated underground water into the sea since shortly after a massive 2011 earthquake and tsunami damaged the complex. Several leaks from tanks storing radioactive water, in recent weeks, have heightened the sense of crisis that the plant’s owner, Tokyo Electric Power Co, isn’t able to contain the problem.

“Instead of leaving this up to TEPCO, the Government will step forward and take charge,” Prime Minister Shinzo Abe said after adopting the outline. “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 (US$470 million) through the end of March 2015 on two projects — 32 billion yen (US$320 million) on the ice wall and 15 billion yen (US$150 million) on an upgraded water treatment unit that is supposed to remove all radioactive elements except water-soluble tritium — according to energy agency official Tatsuya Shinkawa.

The Government, however, is not paying for urgently needed water tanks and other equipment that TEPCO is using to contain leaks. Shinkawa said the funding is limited to “technologically challenging projects”, but the government is open to additional help when needed.

The ice wall would freeze the ground to a depth of up to 30 metres (100 feet) through a system of pipes carrying a coolant as cold as minus 40 degrees Celsius. That would block contaminated water from escaping from the facility’s immediate surroundings, as well as keep underground water from entering the reactor and turbine buildings, where much of the radioactive water has collected.

The project, which TEPCO and the Government proposed in May, is being tested for feasibility by Japanese construction giant Kajima Corp, and is set for completion by March 2015.

Similar methods have been used to block water from parts of tunnels and subways, but building a 1.4-kilometre (0.9-mile) wall that surrounds four reactor buildings and their related facilities is unprecedented.

An underground ice wall has been used to isolate radioactive waste at the US Department of Energy’s former site of the Oak Ridge National Laboratory in Tennessee that produced plutonium, but only for six years, according to the MIT Technology Review magazine.

Some experts are still skeptical about the technology and say the running costs would be a huge burden.