среда, 16 марта 2011 г.
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What is a nuclear meltdown?  jade 04:43:32 |
| | A partial meltdown of nuclear fuel rods has occurred in two, or perhaps three, nuclear reactors at the Fukushima Daiichi power plant in Japan. What does that mean exactly?
“A meltdown is when the uranium dioxide fuel melts*. The melting temperature of uranium dioxide is 2,865 degrees Celsius,” said Martin Bertadono, a nuclear engineer at Purdue University.
Under normal conditions, the uranium dioxide fuel rods* are kept at a temperature below their melting point. Heat emitted* by the rods gets carried away by the water that surrounds it, which is constantly* being pumped through the nuclear core housing the rods. But if the water doesn’t get pumped through quickly enough, it heats up too much and starts boiling and evaporates*.
“As the water boils, the level of water in the reactor drops. If the level drops below the top of the fuel, it starts heating up. If this goes on long enough, about an hour, the uranium begins to melt,” Bertadono said.
“If the water is allowed to boil off completely the whole reactor could melt down,” he said.
By flooding the failed nuclear reactors with seawater, technicians at the Fukushima plant seem to be avoiding a full meltdown, but a partial meltdown has already happened.
What happens when there’s a partial meltdown?
“When the fuel melts, the [nuclear] fission* products can be released from the fuel into the reactor pressure vessel, and then into the containment* if the coolant* leaks from the reactor vessel,” said Taiwo Temipote, a nuclear scientist at Argonne National Laboratory.
http://blog.roodo.com/fashionlife/archives/15349765.html
http://blog.udn.com/leoli/4978731
http://tww86.blog.ithome.com.tw/post/2239/90676
http://coolday.mee.nu/3279763
http://fashionshow99.blogspot.com/2011/03/blog-post_14.html
http://hongkonger.hautetfort.com/archive/2011/03/14/.html
http://daiqianwen.buzzlog.jp/e204198.html
http://jadelung.iza.ne.jp/blog/entry/2195132/
http://socksworld.createblog.com/blog/entry.php?id=109071
http://edeidai.hida-ch.com/e296125.html
http://partick.garment-knitting.com/?p=60 |
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пятница, 10 июля 2009 г.
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| Christmas Minnie jade 04:47:41 |
| | Every afternoon, I take out the pan from the cupboard, cook the porridge. At this moment, can see Christmas Minnie, through the plastic bag, it is still opening eyes wide, the nose exerts all one's effort and dashes for ward forward, the silly appearance is sheer.
Send off by the senior apprentice too. Enter, mail December just, spend Express Mail Service.
Remember he sends messages to me in one weekend, say that does shopping in Carrefour, see flavor is very dense on Christmas. Then ask me for the present. Certainly take. Say, give again, I will go back, tell me, send, go out already, Christmas Mickey . And emphasize that don't buy for him, say he has already crossed age which has wanted the present. In fact he has been only long for ten months for me, but always say we were born in two eras.
In a few days, will get to the office for incoming and outgoing mails the neck of going. The old lady of management is kind, find out for me, look at, " oh, this Christmas gift of yours is very early! " Oh.
Put with the shoes box, use the sticky tape to seal carefully. Did not open until half a day. By the look of a big bow on the cap, it is not Mickey, is a Minnie. Minnie sit Christmas, Christmas cap of DaHong Dai, wear bright red clothes, a white one small to hold in hands one have little gift box all sides of white point while being getting green. Put it on the bed, the color is bright, a group of happy expression.
Put on the desk all the time, has immersed the happy festive air ahead of time. Having just really reached Christmas Day, can't bear to look. Then one set of bags, put in the cupboard containing incidental.
Just, each afternoon, must see it.
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