Workers have discovered new pools of radioactive water leaking from Japan's crippled nuclear complex that officials believe are behind soaring levels of radiation spreading to soil and seawater.
Crews also detected plutonium -- a key ingredient in nuclear weapons -- in the soil outside the complex, though officials insisted Monday the finding posed no threat to public health.
Plutonium is present in the fuel at the complex, which has been leaking radiation for more than two weeks, so experts had expected to find traces once crews began searching for evidence of it this week.
The Fukushima Daiichi power plant was crippled March 11 when a tsunami spawned by a powerful earthquake slammed into Japan's northeastern coast. The huge wave destroyed the power systems needed to cool the nuclear fuel rods in the complex, 140 miles (220 kilometers) northeast of Tokyo.
Since then, three of the complex's six reactors are believed to have partially melted down, and emergency crews have struggled with everything from malfunctioning pumps to dangerous spikes in radiation that have forced temporary evacuations.
Confusion at the plant has intensified fears that the nuclear crisis will continue for months or even years amid alarms over radiation making its way into produce, raw milk and even tap water as far away as Tokyo.
The troubles have eclipsed Pennsylvania's 1979 crisis at Three Mile Island, when a partial meltdown raised fears of widespread radiation release. But it is still well short of the 1986 Chernobyl disaster, which killed at least 31 people with radiation sickness, raised long-term cancer rates and spewed radiation across much of the northern hemisphere.
Tokyo Electric Power Co, which runs the complex, said plutonium was found in soil at five locations at the nuclear plant, but that only two samples appeared to be plutonium from the leaking reactors. The rest came from years of nuclear tests that left trace amounts of plutonium in many places around the world.
Plutonium is a heavy element that doesn't readily combine with other elements, so it is less likely to spread than some of the lighter, more volatile radioactive materials detected around the site, such as the radioactive forms of cesium and iodine.
"The relative toxicity of plutonium is much higher than that of iodine or cesium but the chance of people getting a dose of it is much lower," says Robert Henkin, professor emeritus of radiology at Loyola University's Stritch School of Medicine. "Plutonium just sits there and is a nasty actor."
The trouble comes if plutonium finds a way into the human body. The fear in Japan is that water containing plutonium at the station turns to steam and is breathed in, or that the contaminated water from the station migrates into drinking water.
When plutonium decays it emits what is known as an alpha particle, a relatively big particle that carries a lot of energy. When an alpha particle hits body tissue, it can damage the DNA of a cell and lead to a cancer-causing mutation.
Plutonium also breaks down very slowly, so it remains dangerously radioactive for hundreds of thousands of years.
"If you inhale it, it's there and it stays there forever," said Alan Lockwood, a professor of Neurology and Nuclear Medicine at the University at Buffalo and a member of the board of directors of Physicians for Social Responsibility, an advocacy group.
While parts of the Japanese plant have been reconnected to the power grid, the contaminated water -- which has now been found in numerous places around the complex, including the basements of several buildings -- must be pumped out before electricity can be restored to the cooling system.
That has left officials struggling with two sometimes-contradictory efforts: pumping in water to keep the fuel rods cool and pumping out -- and then safely storing -- contaminated water.
Hidehiko Nishiyama, a spokesman for Japan's Nuclear and Industrial Safety Agency, called that balance "very delicate work."
He also said workers were still looking for safe ways to store the radioactive water. "We are exploring all means," he said.
Meanwhile, new readings showed ocean contamination had spread about a mile (1.6 kilometers) farther north of the nuclear site than before, but was still within the 12-mile (20-kilometer) radius of the evacuation zone. Radioactive iodine-131 was discovered offshore at a level 1,150 times higher than normal, Nishiyama told reporters.
Closer to the plant, radioactivity in seawater tested about 1,250 times higher than normal last week and climbed to 1,850 times normal over the weekend. Nishiyama said the increase was a concern, but also said the area is not a source of seafood and that the contamination posed no immediate threat to human health.
The buildup of radioactive water in the nuclear complex first became a problem last week, when it splashed over the boots of two workers, burning them and prompting a temporary suspension of work.
Then on Monday, Tokyo Electric Power Co officials said workers had found more radioactive water in deep trenches used for pipes and electrical wiring outside three units.
The contaminated water has been emitting radiation exposures more than four times the amount the government considers safe for workers.
The five workers in the area at the time were not hurt, said TEPCO spokesman Takashi Kurita.
Exactly where the water is coming from remains unclear, though many suspect it is cooling water that has leaked from one of the disabled reactors.
It could take weeks to pump out the radioactive water, said Garamage or injuries were reported.
Scores of earthquakes have rattled the country over the past two weeks, adding to the sense of unease across Japan, where the final death toll is expected to top 18,000 people, with hundreds of thousands still homeless.
TEPCO officials said Sunday that radiation in leaking water in Unit 2 was 10 million times above normal -- a report that sent employees fleeing. But the day ended with officials saying that figure had been miscalculated and the level was actually 100,000 times above normal, still very high but far better than the earlier results.
主站蜘蛛池模板： 国内精自视频品线六区免费| 我要看一级毛片| 亚洲精品tv久久久久久久久| 美国免费高清一级毛片| 国产午夜无码视频免费网站| 亚洲欧美日韩精品久久奇米色影视| 在线观看视频免费123| 三上悠亚亚洲一区高清| 日本一区二区三区在线观看视频 | 李老汉在船上大战雨婷| 亚洲欧洲成人精品香蕉网| 特黄大片aaaaa毛片| 免费观看激色视频网站bd| 精精国产www视频在线观看免费| 国产三级精品视频| 鲁大师成人一区二区三区| 国产日韩欧美综合在线| 一级黄色香蕉视频| 国产精品高清久久久久久久| 99在线视频免费观看| 奇米影视奇米四色888av| 一本岛v免费不卡一二三区| 成人爽爽激情在线观看| 久久91精品久久91综合| 日本高清乱理伦片| 久久精品国产色蜜蜜麻豆| 最新版天堂中文在线| 亚洲乱码一区二区三区在线观看| 欧美成人午夜做受视频| 亚洲欧洲精品成人久久曰| 毛片手机在线观看| 国内少妇人妻丰满AV| www.av视频在线| 小蝌蚪影院在线观看| 一级做a爰片久久毛片免费看| 末成年ASS浓精PICS| 亚洲国产日韩在线一区| 欧美日韩国产人成在线观看| 亚洲欧美日韩高清在线电影| 欧美老人巨大xxxx做受视频| 亚洲福利视频网站|