Nuclear Fuel Rod Meltdown 101- Arnie Gundersen explains Fukushima
Zircaloy is one of the major reasons why the Fukushima crisis is scary.
Fairewinds Associates chief nuclear engineer explains the dynamics of the damage in a nuclear reactor meltdown. Rods are made of zircaloy. He demonstrates how Fukushima's zircaloy fuel rods melted and shattered.
*Zircaloy is a problem*
Fuel rods in many types of nuclear reactors consist of pellets of fissile material (uranium and plutonium) sheathed in a metal alloy called zircaloy, made unsurprisingly from zirconium.
Zircaloy seems to be one of the major reasons why the Fukushima crisis is scary. When the earthquake happened, the reactors automatically inserted neutron-absorbing control rods to stop the nuclear chain reaction. This process is called a SCRAM. Despite this, the fuel rods are still producing heat because of other ongoing nuclear reactions (decay heat). This is what makes Zircaloy so worrisome, because when it gets heated up it can oxidize or burn exothermically, producing even more heat. That adds to the risk that fissile material will end up in the wider environment. It also adds to the risk that the nuclear fuel will melt, dribble down to the bottom of the reactor containment vessel, and re-form a critical mass.
That's the really scary possibility, as far as reactors one, two, and three at Fukushima are concerned. If the fissile material in the fuel rods forms a critical mass again, it could melt through the bottom of the containment vessel. It could also trigger a large steam and/or hydrogen explosion that could spread radiation further.
There are other risks with Zircaloy. When hot, it oxidizes in the presence of water, stripping oxygen from water molecules and producing explosive hydrogen. Zircaloy is also what makes spent storage pools so scary. If they lose cooling, the rods can heat up, burn, and release large amounts of radiation into the environment. Cooling ponds are not placed inside containment vessels in the same way reactor cores are.
READ MORE: http://burycoal.com/blog/2011/03/18/zircaloy-is-a-problem/
Original Ustream Video from Crane Camera at Reactor Building 4
http://fairewinds.com/content/ustream-video
*What is Happening in the Reactor Cores of Fukushima Dai-ichi Nuclear Power Station?*
Author: Michio Ishikawa (Chief Adviser of Japan Nuclear Technology Institute (JANTI))
Mar. 24, 2011 account of Fukushima accident.
As you will read, the situation turned much worse than anticipated in his report. Ishikawa compares the situation at Fukushima with the Three Mile Island (TMI) accident. Arnie Gundersen was the vice president of the TMI reactor after the accident and during the years of cleanup, which makes his opinion and knowledge of the Fukushima situation so valuable.
READ MORE: http://www.shimbun.denki.or.jp/en/news/20110324_01.html
Видео Nuclear Fuel Rod Meltdown 101- Arnie Gundersen explains Fukushima канала AFAskygoddess
Fairewinds Associates chief nuclear engineer explains the dynamics of the damage in a nuclear reactor meltdown. Rods are made of zircaloy. He demonstrates how Fukushima's zircaloy fuel rods melted and shattered.
*Zircaloy is a problem*
Fuel rods in many types of nuclear reactors consist of pellets of fissile material (uranium and plutonium) sheathed in a metal alloy called zircaloy, made unsurprisingly from zirconium.
Zircaloy seems to be one of the major reasons why the Fukushima crisis is scary. When the earthquake happened, the reactors automatically inserted neutron-absorbing control rods to stop the nuclear chain reaction. This process is called a SCRAM. Despite this, the fuel rods are still producing heat because of other ongoing nuclear reactions (decay heat). This is what makes Zircaloy so worrisome, because when it gets heated up it can oxidize or burn exothermically, producing even more heat. That adds to the risk that fissile material will end up in the wider environment. It also adds to the risk that the nuclear fuel will melt, dribble down to the bottom of the reactor containment vessel, and re-form a critical mass.
That's the really scary possibility, as far as reactors one, two, and three at Fukushima are concerned. If the fissile material in the fuel rods forms a critical mass again, it could melt through the bottom of the containment vessel. It could also trigger a large steam and/or hydrogen explosion that could spread radiation further.
There are other risks with Zircaloy. When hot, it oxidizes in the presence of water, stripping oxygen from water molecules and producing explosive hydrogen. Zircaloy is also what makes spent storage pools so scary. If they lose cooling, the rods can heat up, burn, and release large amounts of radiation into the environment. Cooling ponds are not placed inside containment vessels in the same way reactor cores are.
READ MORE: http://burycoal.com/blog/2011/03/18/zircaloy-is-a-problem/
Original Ustream Video from Crane Camera at Reactor Building 4
http://fairewinds.com/content/ustream-video
*What is Happening in the Reactor Cores of Fukushima Dai-ichi Nuclear Power Station?*
Author: Michio Ishikawa (Chief Adviser of Japan Nuclear Technology Institute (JANTI))
Mar. 24, 2011 account of Fukushima accident.
As you will read, the situation turned much worse than anticipated in his report. Ishikawa compares the situation at Fukushima with the Three Mile Island (TMI) accident. Arnie Gundersen was the vice president of the TMI reactor after the accident and during the years of cleanup, which makes his opinion and knowledge of the Fukushima situation so valuable.
READ MORE: http://www.shimbun.denki.or.jp/en/news/20110324_01.html
Видео Nuclear Fuel Rod Meltdown 101- Arnie Gundersen explains Fukushima канала AFAskygoddess
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11 апреля 2011 г. 17:50:09
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