TOKYO (AP) - Japan's massive earthquake caused a power outage that disabled anuclear reactor's cooling system, triggering evacuation orders forabout 3,000 residents as the government declared its first-everstate of emergency at a nuclear plant.
Japan's nuclear safety agency said pressure inside one of sixboiling water reactors at the Fukushima Daiichi plant had risen to1.5 times the level considered normal. Hours after the evacuationorder, the government announced that the plant in northeasternJapan will release slightly radioactive vapor from the unit tolower the pressure in an effort to protect it from a possiblemeltdown.
Chief Cabinet Secretary Yukio Edano said the amount ofradioactive element in the vapor would be "very small" and wouldnot affect the environment or human health. "With evacuation inplace and the ocean-bound wind, we can ensure the safety," he saidat a televised news conference early Saturday.
After the quake triggered a power outage, a backup generatoralso failed and the cooling system was unable to supply water tocool the 460-megawatt No. 1 reactor, though at least one backupcooling system was being used. The reactor core remains hot evenafter a shutdown.
The agency said plant workers are scrambling to restore coolingwater supply at the plant but there is no prospect for immediatesuccess.
Edano said the 40-year-old plant was not leaking radiation. Theplant is in Onahama city, about 170 miles (270 kilometers)northeast of Tokyo.
If the outage in the cooling system persists, eventuallyradiation could leak out into the environment, and, in the worstcase, could cause a reactor meltdown, a nuclear safety agencyofficial said on condition of anonymity, citing sensitivity of theissue.
Another official at the nuclear safety agency, Yuji Kakizaki,said that plant workers were cooling the reactor with a secondarycooling system, which is not as effective as the regular coolingmethod.
Kakizaki said officials have confirmed that the emergencycooling system - the last-ditch cooling measure to prevent thereactor from the meltdown - is intact and could kick in ifneeded.
"That's as a last resort, and we have not reached that stageyet," Kakizaki added.
Japan's nuclear safety agency said the evacuation, ordered bythe local government of Fukushima, affects at least 2,800 people.Edano said residents were told to stay at least two miles (threekilometers) from the plant and to stay inside buildings.
He said both the state of emergency and evacuation order areprecautionary measures.
"We launched the measure so we can be fully prepared for theworst scenario," he said. "We are using all our might to deal withthe situation."
Defense Ministry official Ippo Maeyama said the ministry hasdispatched dozens of troops trained for chemical disasters to theFukushima plant in case of a radiation leak, along with fourvehicles designed for use in atomic, biological and chemicalwarfare.
Pineville, La., resident Janie Eudy said her husband, Danny, wasworking at Fukushima No. 1 when the earthquake struck. After aharrowing evacuation, he called her several hours later from theparking lot of his quake-ravaged hotel.
He and other American plant workers are "waiting to be rescued,and they're in bad shape," she said in a telephone interview.
Danny Eudy, 52, a technician employed by Pasadena, Texas-basedAtlantic Plant Maintenance, told his wife that the quake violentlyshook the plant building he was in. "Everything was falling fromthe ceiling," she said.
Eudy told his wife that he and other workers were evacuating theplant when the tsunami swept through the area, carrying away homesand vehicles. They retreated so they wouldn't get caught up in theraging water.
"He walked through so much glass that his feet were cut. Itslowed him down," she said.
After the water started to recede, Eudy and other workers droveto their hotel, only to find it in shambles.
"Most of the hotel was gone," she said. "He said the roads weretorn up and everything was a mess."
His hotel room was demolished along with all of his belongings,so Eudy had to borrow a resident's phone to call his wife earlyFriday morning. The workers were waiting for daylight butcontemplating seeking higher ground in case another big wavehit.
"He sounded like he was in shock. He was scared," Janie Eudysaid. "They're totally on their own, trying to just make it."
Neil Sheehan, a spokesman for the U.S. Nuclear RegulatoryCommission, said staff were trying to collect more information onwhat was happening.
At the Fukushima Daiichi site, "They are busy trying to getcoolant to the core area," Sheehan said. "The big thing is tryingto get power to the cooling systems."
Speaking at the White House, Secretary of State Hillary Clintonalso said U.S. Air Force planes were carrying "some reallyimportant coolant" to the site. She said "one of their plants cameunder a lot of stress with the earthquake and didn't have enoughcoolant."
High-pressure pumps can temporarily cool a reactor in this statewith battery power, even when electricity is down, according toArnold Gundersen, a nuclear engineer who used to work in the U.S.nuclear industry. Batteries would go dead within hours but could bereplaced.
The nuclear reactor was among 10 in Japan shut down because ofthe earthquake.
The Fukushima plant is just south of the worst-hit Miyagiprefecture, where a fire broke out at another nuclear plant. Theblaze was in a turbine building at one of the Onagawa power plants.Smoke could be seen coming out of the building, which is separatefrom the plant's reactor, Tohoku Electric Power Co. said. The firehas since been extinguished.
Another reactor at Onagawa was experiencing a water leak.
The U.S. Geological Survey said the 2:46 p.m. quake was amagnitude 8.9, the biggest earthquake to hit Japan since officialsbegan keeping records in the late 1800s.
A tsunami warning was issued for a number of Pacific, SoutheastAsian and Latin American nations.
At the two-reactor Diablo Canyon plant at Avila Beach, Calif.,an "unusual event" - the lowest level of alert - was declared inconnection with a West Coast tsunami warning. The plant remainedstable, though, and kept running, according to the NRC.
AP National Writer Jeff Donn reported from Boston. AssociatedPress writer Michael Kunzelman in New Orleans contributed to thisreport.