TOKYO — The Japanese government announced Tuesday it will spend $470 million on a subterranean ice wall and other steps in a bid to stop leaks of radioactive water from the crippled Fukushima nuclear plant after repeated failures by the
TOKYO — The Japanese government announced Tuesday it will spend $470 million on a subterranean ice wall and other steps in a 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 the nuclear accident won’t be a safety concern just days before the International Olympic Committee chooses on Sept. 7 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.
“The world is watching if we can properly handle the contaminated water but also the entire decommissioning of the plant,” Prime Minister Shinzo Abe said.
The government plans to spend the $470 million through March 2015 on two projects — $320 million on the ice wall and $150 million on an upgraded water treatment unit to remove 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 TEPCO is using to contain leaks.
The ice wall would freeze the ground to a depth of 100 feet through a system of pipes carrying a coolant as cold as minus 40 F. 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.
Similar methods have been used to block water from parts of tunnels and subways, but building a 0.9-mile-wide 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 U.S. 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 said running costs could be a huge burden.
Atsunao Marui, an underground water expert at the National Institute of Advanced Industrial Science and Technology, said a frozen wall could be watertight but is normally intended for use for a few years and is not proven for long-term use as planned in the outline. The decommissioning process takes about 40 years.
Marui said additional measures should be taken now to stop contaminated water leaking further out at sea.
TEPCO has been pumping water into the wrecked reactors to cool nuclear fuel that melted when the 2011 earthquake and tsunami knocked out the plant’s power and cooling systems. The utility has built more than 1,000 tanks holding 335,000 tons of contaminated water at the plant, and the amount grows by 400 tons daily.
After spending on the ice wall, the remainder of the funding will go to the development and production of a water treatment unit that can treat larger amounts of contaminated water more thoroughly than an existing machine, which is under repair after corrosion was found during a test run.
Nuclear Regulation Authority Chairman Shunichi Tanaka has said the contaminated water cannot be stored in tanks forever and must be released into the sea after being processed and diluted, but only with local consent.
Other measures include replacing rubber-seamed storage tanks with more durable welded tanks and pumping out untainted underground water further inland for release into the sea to reduce the total amount of water flowing into the plant site. About 1,000 tons of underground water runs into the complex daily.
TEPCO is also constructing an offshore wall of steel panels to keep contaminants from spreading further into the sea. The utility said radioactive elements have mostly remained near the embankment inside the bay, but experts have reported offshore “hot spots” contaminated with high levels of cesium.
