【正文】 said there was “no immediate health hazard” to residents from the leaks, which they described as “minute,” and people were urged to stay calm.The emergency at the Daiichi plant began shortly after the earthquake struck on Friday afternoon. Emergency diesel generators, which had kicked in to run the reactor’s cooling system after the electrical power grid failed, shut down about an hour after the earthquake. There was speculation that the tsunami knocked the generators out of service.Twenty hours later, the plant was operating in a batterycontrolled cooling mode. Tokyo Electric said that by Saturday morning it had installed a mobile generator at Daiichi to ensure that the cooling system would continue operating even after reserve battery power was depleted. Even so, the pany said it was considering a “controlled containment venting” in order to avoid an “uncontrolled rupture and damage” to the containment unit.“With evacuation in place and the oceanbound wind, we can ensure the safety,” a nuclear safety official, Yukio Edano, said at a news conference early Saturday.It was not clear, however, how long the cooling systems could continue to function in emergency mode or when normal power supplies could be restored.Two workers were reported missing at the Daiichi plant, but the pany did not explain what might have happened to them.A pump run by steam, designed to function in the absence of electricity, was adding water to the reactor vessel, and as that water boiled off, it was being released. Such water is usually only slightly radioactive, according to nuclear experts. As long as the fuel stays covered by water, it will remain intact, and the bulk of the radioactive material will stay inside. If the fuel is exposed, it can result in a meltdown.The reactors at the two plants shut down when the earthquake began at 2:46 . Friday. At the Daiichi plant’s Reactor Unit 1, when the emergency generators shut down, pressure began to rise in the reactor, leading operators to vent it.During much of the early morning on Saturday, safety officials focused on getting emergency power supplies to the Daiichi plant to restore the normal cooling function.Secretary of Stateafter the plants were shut down, as they were during the quake.About 45,000 people were affected by the evacuation order at the Daiichi plant, where those living within a sixmile radius were told to leave. The evacuation of the second plant was for a onemile radius because “there is no sign that radiation has been emitted outside,” an official said.Failure of the cooling systems allowed pressure to build up beyond the design capacity of the reactors. Small amounts of radioactive vapor were expected to be released into the atmosphere to prevent damage to the containment systems, safety officials said. They said that the levels of radiation were not large enough to threaten the health of people outside the plants, and that the evacuations had been ordered as a precaution.Nuclear safety officials focused initially on the Daiichi plant. But by Saturday morningMATTHEW L. WALDWASHINGTON — Japanese officials issued broad evacuation orders on Saturday for people living near two nuclear power plants whose cooling systems broke down as a result of the earthquake. The officials warned that small amounts of radioactive material were likely to leak from the plants.The power plants, known as Daiichi and Daini and operated by Tokyo Electric Power, experienced Mike Hale from Honolulu。 Michael Schwirtz from Moscow。 Kevin Drew and Bettina Wassener from Hong Kong。 Ken Belson, Maria Newman and Henry Fountain from New York。United States Geological Surveysaid the United States “stands ready to help” Japan deal with the aftermath. “Michelle and I send our deepest condolences to the people of Japan,” he said in a statement. He later spoke with Mr. Kan and offered assistance.American military airfields in Japan began accepting civilian flights diverted from airports that suffered damage, American officials said early Friday.A spokesman for the American Seventh Fleet in Japan said Naval Air Field Atsugi had received several mercial passenger planes that could not land at Narita airport outside Tokyo. Officials said Yokota Air Base also received civilian flights. Three American warships in Southeast Asia will be ordered out to sea to reposition themselves in case they need to provide assistance, a fleet spokesman said.The tsunami assaulted Hawaii with sevenfoot waves, although it caused little damage. Powerful surges that hit the West Coast of the United States caused boats to sink in Santa Cruz Harbor. The Coast Guard reported that one person was swept to sea near McKinleyville, Calif., while trying to take pictures of the waves, and a search had begun.In Japan, the Tokyo subways emptied, and airports were closed. Many residents set off on epic journeys home, walking for miles across a vast metropolitan area. In a video posted on YouTube, rumbles shook a supermarket as shopkeepers rushed to steady toppling wares and a classical music soundtrack played.OnNaoto KanSouthern Methodist UniversityquakeimagesJapan目錄QUAKE AND TSUNAMI LEAVE WAKE OF DESTRUCTION ACROSS NORTHERN JAPAN 1JAPAN ORDERS EVACUATION NEAR 2ND NUCLEAR PLANT 5JAPAN’S STRICT BUILDING CODES SAVED LIVES 9QUAKE AND TSUNAMI LEAVE WAKE OF DESTRUCTION ACROSS NORTHERN JAPAN 12JAPAN’S INDUSTRIAL HEART ESCAPES HEAVIEST BLOWS 16March 11, 2011Quake and Tsunami Leave Wake of Destruction Across Northern JapanByMARTIN FACKLERTOKYO — Rescuers struggled to reach survivors on Saturday morning asreeled after an earthquake and a tsunami struck in deadly tandem. The earthquake set off a devastating tsunami that sent walls of water washing over coastal cities in the north. Concerns mounted over possible radiation leaks from two nuclear plants near the earthquake zone.The death toll from the tsunami and earthquake, t