SEOUL, South Korea -- The Japanese government on Tuesday pledged nearly $500 million to fight toxic water leaks at the Fukushima Daiichi plant, part of an increasingly precarious nuclear cleanup job that Prime Minister Shinzo Abe says requires "radical measures."
Concerns about fast-accumulating contaminated water at the plant, nearly 2 1/2 years after an earthquake triggered a major nuclear accident, have pushed the government to invent on-the-fly solutions.
For example, part of the funds announced Tuesday will be used to pump coolant through underground pipes around critical buildings, officials said, freezing soil and creating a de facto "seal" that will measure almost a mile in length.
The announcement suggests mounting problems at Fukushima, where hundreds of tons of irradiated water flow daily into the sea. It also marks the government's most direct attempt yet to take charge of a site operated by the Tokyo Electric Power Co., or TEPCO, which has been criticized by regulators for lax oversight.
The 2011 nuclear crisis at Fukushima involved three reactor meltdowns and a massive release of radiation that forced the evacuation of 160,000 residents. The government has since declared the plant in a state of "cold shutdown," meaning its reactor cores are stable. But analysts say that term belies the complex and environmentally damaging problems that Japan could face during decades of cleanup.
The greatest challenge, for now, is the water. When a nuclear plant is operating as designed, irradiated water is contained. But the Fukushima plant -- battered by the 9.0-magnitude earthquake and enormous tsunami, and now relying on makeshift equipment -- has become a soggy mess.
Every day, roughly 400 tons of groundwater flows from surrounding mountains and seeps into reactor buildings, TEPCO says. There, it mixes with highly toxic water used to douse and cool the crippled reactor cores.
Some of the water leaks into the sea, TEPCO says, although the exact path -- whether through cracks in buildings or pipes or trenches -- remains unclear. Workers, speaking occasionally to the media, say they are in a perpetual fight to drain toxic water from areas where it should not be and store it in containers.
So far, the company has pumped the water into nearly a thousand gray drums, each the size of a small home. But those drums were hastily constructed, regulators say, using some parts that were bolted, not welded, together.
Last month, TEPCO admitted that one storage drum had sprung a leak. Spiking radiation levels around the tanks have raised fears that others could be leaking as well. But it is hard to tell: Water levels in the tanks have not been measured on a regular basis, Shunichi Tanaka, chairman of the Nuclear Regulation Authority, said at a news conference Monday. "We believe that management of and monitoring of tanks represents a serious problem," Mr. Tanaka said, adding that regulators have given TEPCO "strict instructions" to strengthen their oversight.
Among other actions, Japan's government plans to seal off reactor buildings and upgrade a system to remove radionuclides from the contaminated water on the site.
At a meeting Tuesday, Mr. Abe and other Japanese officials said the central government, not TEPCO, should take the lead in handling technically challenging problems at the plant, according to public broadcaster NHK.