Eric Roberts <[email protected]> wrote: > > Just got a CNN alert saying that a 3rd reactor exploded in Japan.. > http://news.yahoo.com/s/time/20110313/wl_time/08599205861500
The reported presence of Cesium 127 was disturbing because the element is usually evidence that the reactor core has overheated, if only for a portion of time. The radioactive debris is produced when the core is exposed above the coolant water level and then overheats. All it takes is 20 to 50 minutes of exposure to produce enough heat to let off Cesium 127. One of the other potential by-products of such overheating is hydrogen, which is produced when the zirconium sheaths around the uranium rods form a chemical reaction with the heat and steam. Hydrogen is believed to be the cause of the explosion at Fukushima on Saturday that was captured on videotape and alarmed not only Japan but most of the watching world. What happens next depends on whether enough coolant is reintroduced or whether the uranium rods are cooling fast enough on their own to avoid a meltdown. It also depends on how old the fuel rods are: fresher rods cool down faster; older ones take much longer. The harbinger in this regard is that Fukushima's reactors are of a decades-old design and unit 1 was reportedly scheduled to be retired later this month. <http://us.rd.yahoo.com/dailynews/time/wl_time/storytext/08599205861500/40647446/SIG=11v6plhbc/*http://www.time.com/time/photogallery/0,29307,1887705,00.html> If the rods remain hot enough and exposed above the necessary level of cooling water, they will start to melt. If this condition - called slumping - is unarrested, the material will eventually puddle on the containment floor and probably eat away at it, eventually becoming exposed to the external environment. There is still a possibility of introducing enough coolant before that happens to impede damage, but because the geometry of the rods - their very shape - is lost through melting, water's ability to wrap around and cool the radioactive material is greatly diminished. What you have is a large amount of liquid sitting above deadly sludge but not completely enveloping it, and so it continues to eat away at the bottom. All of this can happen in a matter of days. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~| Order the Adobe Coldfusion Anthology now! http://www.amazon.com/Adobe-Coldfusion-Anthology/dp/1430272155/?tag=houseoffusion Archive: http://www.houseoffusion.com/groups/cf-community/message.cfm/messageid:335052 Subscription: http://www.houseoffusion.com/groups/cf-community/subscribe.cfm Unsubscribe: http://www.houseoffusion.com/groups/cf-community/unsubscribe.cfm
