Japan's Tokyo Electric Power Co hopes to achieve a "cold shutdown" of its crippled Fukushima Daiichi nuclear plant in six to nine months, setting a clear timeframe for bringing the nuclear crisis under control.
Tepco said that within three months it plans to cool reactors and spent fuel at the nuclear plant to a stable level and get radiation leaks on a downward trend.
In another three to six months Asia's largest utility aims to secure a "cold shutdown" at the plant, a state in which the water cooling fuel rods is below 100 degrees celsius and the reactors are considered stable.
Tepco has been struggling to stabilise the Fukushima complex, 240 km north of Tokyo, since it was seriously damaged by the March 11th earthquake and tsunami.
The announcement came as US secretary of state Hilary Clinton urged Japan to remain active on the world stage.
"Economically, diplomatically and in so many other ways, Japan is indispensable to global problem-solving," Ms Clinton told a news conference after talks with Japanese foreign minister Takeaki Matsumoto. "And the US-Japan alliance is as indispensable as ever to global security and progress."
Ms Clinton also said Japan and the United States had agreed to create a "public-private partnership for reconstruction" under the guidance of Japan's government, and that US firms and organisations would begin discussing how they can support Japan as it comes through the crisis.
She said there was no reason for Americans to stay away from Japan, other than the area around the nuclear plant.
"We have encouraged businesses and other Americans to go on with their normal lives and to travel to Japan for business and other reasons," she said.
Ms Clinton is the highest-ranking US official to visit in a gesture of solidarity with Japan, one of Washington's closest Asian allies, since it was engulfed in its worst crisis since World War Two.
Her 5-1/2-hour stop comes after a week in which the Japanese government put its nuclear calamity on a par with the world's worst nuclear disaster, Chernobyl, after new data showed that more radiation had leaked from the Fukushima Daiichi power plant than first thought.
Shares of Tepco have lost three-quarters of their value since the quake amid worries over whether it would survive the crisis, with one analyst estimating compensation claims could reach $130 billion.
"This is the biggest crisis since the founding of our company," Tepco chairman Tsunehisa Katsumata told a briefing in Tokyo, adding that he would likely resign to take responsibility, possibly after a shareholders' meeting in June.
"Getting the nuclear plant under control, and the financial problems associated with that...How we can overcome these problems is a difficult matter."
Tepco and the government have been under pressure to offer a roadmap for containing the crisis and to clarify when those who have had to evacuate the area around the damaged plant will be able to go home.
Prime Minister Naoto Kan has faced criticism over comments, which he later denied making, suggesting evacuees from the area around the Fukushima plant may not be able to return for 10 or 20 years.
The government has expanded a 20-km (12-mile) evacuation zone around the plant because of high accumulated radiation.
After achieving a cold shutdown at the six-reactor plant, Tepco said it would then focus on longer-term issues such as encasing the reactor buildings, cleaning up contaminated soil, and removing nuclear fuel to a safe holding place.
Reuters