TOKYO -- Japan said Monday it will stabilize and shut down its stricken nuclear power plant in six to nine months, as planned, as residents of two more towns around it evacuated amid concerns about accumulated radiation.
The government's timeline for stabilizing the plant was called into question last week after new data showed that the damage to one reactor at the Fukushima Dai-ichi nuclear complex was worse than expected. That assessment also prompted the government to acknowledge that the reactor's fuel rods had mostly melted soon after the March 11 earthquake and tsunami knocked out the plant's cooling system.
Until all the reactors are safely shut down, they continue to leak radiation, though in much smaller amounts than in the early days of the disaster. Still, the sheer volume of contaminants spewed from the plant -- and their buildup in places outside the 12-mile (20-kilometer) evacuation zone -- persuaded the government to order residents to leave more towns in late April. Some of those evacuations began this weekend.
In a rare bit of good news, authorities said Monday that their original timeline for stabilizing the reactors is achievable because the temperature inside the Unit 1 reactor core has fallen to nearly 100 Celsius (212 F), a level considered safe and close to a cold shutdown.
"We believe we can stick to the current timeframe," said Goshi Hosono, the prime minister's aide and nuclear crisis task force director, referring to the timeline laid out in April of bringing the plants three troubled reactors to a cold and stable shutdown in six to nine months.
"What's crucial is how we can proceed with cooling. Even though the cores had melted, they are somewhat kept cool," Hosono said.
The plant, operated by the Tokyo Electric Power Co., is still leaking a massive amount of contaminated water -- just one of many problems facing workers who have been trying to bring it under control the last two months.
Plant workers plan to pump highly radioactive water swelling inside the Unit 3 turbine building to a makeshift storage. TEPCO took a similar step with contaminated water from another reactor after a massive leak into the Pacific in April triggered criticism in and outside Japan.
On Monday, the operator released data from initial hours of the crisis for the first time, complying with a government request. TEPCO spokesman Junichi Matsumoto said there was no indication that the quake caused damage to key reactor parts or equipment, confirming the narrative that the tsunami was the cause of the crisis.
Hosono said Monday that a similar meltdown had probably occurred Units 2 and 3 as they were both out of water for more than six hours after the March 11 power outage. Unit 1's reactor core was out of water for more than 14 hours, he revealed Monday.
Most of the fuel in Unit 1 has melted and slumped to the bottom of the pressure vessel that holds the rods together, and some of that ate through the vessel and trickled into the large beaker-shaped containment vessel, officials said.
TEPCO on Monday said there was no early indication released preliminary plant data in early hours of the crisis for the first time since the disaster, but denied speculation that there were no early indication of damage to key parts including ducts,
Meanwhile, about 50 residents from Kawamata and 64 from Iitate vacated their homes over the weekend and began to adjust to life in evacuation centers after leaving their homes over the weekend on previous government orders.
About 6,700 people remain in the two areas and are expected to leave by the end of June.
The towns are among several that have registered relatively high radiation readings but are outside a previous 12-mile (20-kilometers) radius evacuation zone around the nuclear plant.
In late April, the government said residents in these areas should prepare to evacuate over the coming month due to concerns about cumulative radiation.
Officials in Iitate said they intend to have most of the town's residents evacuated by the end of the month. The scenic, rural village had a population of 6,500 before the earthquake and about 2,000 people have already moved out voluntarily.
On Sunday, four families with babies or pregnant women left the town, according to an Iitate official who did not give his name because he was not authorized to speak to the media.
He said it is difficult to estimate how many people remain in the town because many are evacuating on their own and the village does not have details on their circumstances.
Officials said they have not set an exact date for the final evacuations because some residents may have trouble leaving -- because they own livestock or for other reasons -- and may require extra time.
While Japan worked to move people farther away from the plant, the United States loosened some of its guidance for its citizens in Japan -- which has been more stringent than Tokyo's.
Washington has recommended that Americans stay at least 50 miles (80 kilometers) from the plant, but an updated travel alert Monday said that it was safe for people to transit through that zone using a highway and rail line.
Associated Press writers Eric Talmadge in Tokyo and Matthew Pennington in Washington contributed to this report.