日本地震毀壞的核反應堆麻煩增加
An explosion blew the roof and outer walls off of the number 3 unit Monday at the Fukushima nuclear power plant in earthquake-stricken northern Japan.
A similar explosion struck the number 1 unit on Saturday at the plant, where cooling systems were knocked out by Friday's devastating earthquake and tsunami. Officials said the inner containment vessel remained intact after Monday's explosion and they did not believe there had been a major release of radiation.
However engineers were still struggling to gain control of a new threat at the number 2 unit, where officials reported a total failure of the cooling system. The operators of the plant, Tokyo Electric Power Company, said the coolant had evaporated exposing the fuel rods, raising the risk of them melting down.
If the heat from a meltdown ruptures the containment vessel, that could permit a major release of radiation with serious health consequences. Engineers were desperately pumping sea water into all three units at Fukushima in an effort to cool them down.
Engineers have also vented steam from the plants to release a build-up of pressure. Hydrogen in the steam is believed to have mixed with oxygen, causing the two explosions.
Almost 200,000 people have already been evacuated from areas around Fukushima and other troubled nuclear power stations. About 600 people still in homes near the Fukushima plant were advised to remain indoors.
The commander of the aircraft carrier USS Ronald Reagan, which has been assisting in relief efforts from about 160 kilometers offshore, said the American fleet had moved away from the Fukushima plant after low levels of radiation were detected on 17 crewmen. He said the radiation was easily washed off.
The nuclear crisis has diverted attention away from a massive rescue and relief effort. The total death toll from the quake and tsunami is expected to reach more than 10,000.
日本北部遭受地震的福島核電站星期一發生爆炸，炸燬了3號機組的外牆和屋頂。
這個核電站的1號機組星期六發生了類似的爆炸。星期五毀滅性的地震和海嘯導致這個核電站的冷卻系統失靈。官員們說，星期一的爆炸發生後，1號反應堆內部安全罩仍完好無損。他們相信沒有釋放出大量的輻射。
但是，工程師們仍在努力控制2號反應堆面臨的新威脅。那裏的官員們報告說冷卻系統已經完全失靈。這個核電站的運營商東京電力公司表示，冷卻劑已經揮發，導致燃料棒暴露在外，增加了燃料棒熔化的危險。
如果溶化時產生的熱量使安全罩出現破裂，可能會導致一次嚴重危害人體健康的重大輻射。工程師們正竭力地向福島核電站的3個反應堆注入海水，努力使它們降溫。
工程師們還排放了核電站產生的蒸汽，以釋放積聚的壓力。據信，蒸汽中的氫氣混合了氧氣，導致了這兩次爆炸。
將近20萬人已經從福島核電站以及其它被毀壞的核電站周圍地區撤離。仍住在福島核電站附近的大約600人被勸告呆在戶內。
從距離海岸約160公里的海域前來救災的美國“里根號”航空母艦的艦長說，在17名船員身上發現了低水平的放射性輻射後，這個美國艦隊已經駛離福島核電站。他表示，這種放射性輻射很容易就能沖洗掉。
這次核危機分散了人們對大規模救援和救災工作的注意力。地震和海嘯造成的總死亡人數預計將超過一萬人。
