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Tokyo Utility Lays Out Plan for Its Reactors

TOKYO — The Tokyo Electric Power Company laid out an ambitious plan on Sunday for bringing the reactors at its hobbled Fukushima Daiichi nuclear power plant into a stable state known as cold shutdown within the next nine months and for trying to reduce the levels of radioactive materials being released in the meantime.

The blueprint for action represents Tokyo Electric’s most concrete timetable yet for controlling the reactors and improving safety at the plant, which was damaged by a massive earthquake and tsunami nearly six weeks ago.

The first part of the plan, expected to take three months, would include building new cooling systems, critical to preventing catastrophic releases of radioactive materials. The company then hopes to cover three badly damaged reactor buildings and install filters to reduce contamination being released into the air.

By announcing the construction of new cooling systems, the company implicitly acknowledged what outside experts had been warning for weeks: that the company’s earlier plan to repair the existing system was unlikely to work because the equipment was too badly damaged. The change in approach means that the country must resign itself to several more months of radioactive emissions — into the air and possibly into the Pacific — even though the plant appears to be less volatile than it was.

For weeks, workers have been consumed with reacting to a cascade of problems created not only by the original disasters but also by makeshift fixes for bringing the plant under control. By making its announcement on Sunday, Tokyo Electric was trying to show that conditions had apparently improved enough in recent days that it was now able to turn some of its attention to planning for the future.

“The company has been doing its utmost to prevent a worsening of the situation,” Tokyo Electric’s chairman, Tsunehisa Katsumata, told a news conference.

“We have put together a road map,” he said, adding, “We will put our full efforts into achieving these goals.”

On Sunday, meanwhile, the government said that evacuees who were forced to leave their homes near the Daiichi plant will be able to start returning in six to nine months, after the land is decontaminated. The announcement seemed to suggest that few places would be put off limits, as they were after the more devastating 1986 Chernobyl disaster in Ukraine. But Japanese officials did not provide specifics about how contaminated the land was within several miles of the plant.

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The chairman of Tokyo Electric, Tsunehisa Katsumata, at a news conference on Sunday in Tokyo.Credit...Issei Kato/Reuters

In any case, the statements were the clearest indication yet that the tens of thousands of people evacuated from the area and living in shelters will not soon be able to return to their homes, or to towns that were destroyed by the tsunami. It also means that the badly shaken government will have to continue to provide for the displaced people even as it struggles to rebuild from the quake and stabilize the economy.

One government official and a nuclear power expert said they thought Tokyo Electric’s plan could work, although one said the company should try for a cold shutdown sooner. A cold shutdown means that the temperature of the water in a reactor is below the boiling point. Although cooling must continue, the water will not boil away quickly, even at atmospheric pressure.  Boiling must be avoided because fuel rods have to be kept under water to avoid meltdown.

The Japanese government and the company, known as Tepco, have been overly optimistic in the past. Several weeks ago, for instance, the company said it hoped that its success in bringing live power lines back to the plant would enable workers to quickly restart the existing cooling systems even though the equipment would have had to survive not just the natural disasters, but the explosions that rocked the plant in the following days.

The announcement on Sunday that new cooling systems would be built was the first admission that efforts to restart the old system had failed.

Hidehiko Nishiyama, deputy director general of the Nuclear and Industrial Safety Agency, said that although it was not yet possible to know for sure, “there is a possibility that normal cooling systems cannot be revived.”

In a show of support, Secretary of State Hillary Rodham Clinton flew to Japan on Sunday from Seoul, South Korea, becoming the most senior American official to visit since the disaster. She told Japan’s foreign minister, Takeaki Matsumoto, that her visit reflected “our very strong bonds of friendship that go very deep into the hearts of our people.”

Mrs. Clinton said that the United States was “doing everything we can to support Japan, and we have very good cooperation.” The United States military has participated in rescue efforts in Japan, even after some personnel were exposed to radiation, and Americans quietly helped reopen the airport in Sendai.

While it remains difficult to answer some important questions about the safety of the Fukushima Daiichi plant, in part because it is too contaminated now for workers to get close to the reactors, the State Department said last week that the situation at and around the plant had become less perilous.

Since the cooling systems at the plant failed, Tokyo Electric has been cooling the reactors and the pools that hold used, but still hot, fuel rods by pouring tons of water on them. But as the water boils in the reactors, pressure rises too high to pump in more water, so workers have to vent to the atmosphere and feed in more water, a procedure known as “feed and bleed.”

That means the plant is consistently spewing radioactive materials into the air. And although much of the water that is used evaporates, tons of runoff have also been created.

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A robot measuring radiation levels at the Fukushima Daiichi plant.Credit...Tokyo Electric Power Co, via Reuters

The jury-rigged system has become more efficient in recent weeks.

Immediately after the quake, helicopters dropped water on the reactor buildings and workers sprayed water into them with fire hoses. The company has since set up large pumping trucks at the reactors. At some reactors, the arms of the trucks that deliver the water have been placed over the damaged walls of the buildings, enabling water to be shot more directly at the reactors and pools and reducing runoff.

The long-term solution announced Sunday, to build new cooling systems, would eliminate the runoff because it would be a closed loop, like the systems previously used at the plant. Such systems cool the steam that comes off the reactors, creating water, which is pumped back into the reactors. The systems would also stop venting, if they worked correctly.

Until the new system can be built, Tokyo Electric intends to set up a water processing unit that removes radioactive particles and salt, and store it in tanks. But in a sign of how much improvisation has gone into the plan, company officials said that they would turn a concrete-walled waste treatment building into a large storage tank to hold up to 30,000 tons of contaminated water.

The company plans to place temporary covers over three of the six reactor buildings at the plant and install air filters to help reduce the venting, the company said. Engineers will also start designing structures with concrete roofs and sides.

Officials said the temporary covers would be made of material similar to the tough fabric used to wrap buildings under construction. The company warned that the covers could be damaged in a typhoon.

Goshi Hosono, a special adviser to Prime Minister Naoto Kan, identified two risks to the company’s plans: that the new cooling systems would be too hard to build quickly and that a serious aftershock or tsunami could lead to further damage at the site before changes could be made.

Hironobu Unesaki, a professor at the Research Reactor Institute at Kyoto University, said the long-term plan seemed mostly sound. But he said the company should try to achieve cold shutdown of the reactors sooner than six to nine months, to reduce the risk of a large-scale radiation release.

Mrs. Clinton’s visit followed several weeks in which the United States indirectly criticized Japan’s response to the nuclear disaster, saying it was worse than Japanese officials were acknowledging and declaring a broader evacuation zone around the plant for Americans in Japan.

Asked Sunday if the Japanese government had acted transparently enough, Mrs. Clinton said: “We have been very supportive of what Japan is doing to take the appropriate steps.”

Mrs. Clinton also met with Emperor Akihito and Empress Michiko at the Imperial Palace. The emperor shook her hand, and Mrs. Clinton kissed Michiko on both cheeks. “I’m so, so sorry for everything your country is going through,” she told them, before they entered the palace for tea.

Reporting was contributed by Keith Bradsher, Ken Ijichi, Yasuko Kamiizumi, Andrew Pollack, Kantaro Suzuki and Hiroko Tabuchi from Tokyo, and Matthew L. Wald from Washington.

A version of this article appears in print on  , Section A, Page 1 of the New York edition with the headline: Tokyo Utility Lays Out Plan For Its Reactors. Order Reprints | Today’s Paper | Subscribe

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