Posted on 03/15/2011 3:09:28 PM PDT by The Magical Mischief Tour
CNN had a GE engineer (that quit because of the saftey of these reactors) on then subsequently a past NRA admin guy and both adressed the cooling donut. The Torus was to be even less fortified then planned, but NRA guy said GE beefed the design up before install to address the engineers concern.
Interesting stuff, however I would take it that there is for sure a breach in Reactor number 2.
You’re right about GE...
IBTZ
Good observations. I’m hearing that they’re going to try again (with water and boric acid). If this site is right, it’s as you mentioned:
“...Both units 1 and 3 have no roof after earlier blasts, making it easy to dump water onto them, he said. Unit 4 has holes in the building, allowing fire trucks to spray water inside...”
But I’m not sure if this will present any problems with the design of the reactor:
“...Boric acid contains boron, which helps slow nuclear reactions by absorbing neutrons, said Naj Meshkati, a nuclear power plant safety expert at the University of Southern California. But the same acid also melted away steel when it was used repeatedly at a troubled northern Ohio nuclear plant.”
http://www.cp24.com/servlet/an/local/CTVNews/20110315/110315_japan_quake/20110315/?hub=CP24Home
“Maybe if they keep an updated chart like this, we can circumvent the media hysteria circus and know much better what is going on.”
Yeah, I would just check JAIF for updates- they’ve been pretty thorough with both the status of the reactors and updated earthquake info.
Are you connecting Michelle's cousin to Japan or just recounting recent events?
The cousin is a college student who went missing in, I think, Washington State and prior to Friday.
So?
Thanks for the info and links. If I’m reading this right, boric acid on the spent rods might hurt the containment steel. I read the cores should be much cooler now...
Wish I knew what caused the spike. Hopefully it won’t last and hinder work on the spent rods...
Anyway, great charts/graphs, etc. you’ve been posting. Appreciate them very much.
There is one and only one way for Hydrogen to be produced in large enough quantities to produce an explosion. Namely, H is produced as a result of a chemical reaction with the zirconium in the Zircaloy cladding of the fuel rods. And this chemical reaction takes place when the fuel rods reach a temperature of 1200 C (2200 F). Hence the presence of H means the rod temp has reached at least 1200 C. For at least the top parts of the fuel rods.
And this means that the water is boiling away (or leaking) faster than it can be replaced. Because no parts of the fuel rods could reach that temperature if they were completely surrounded by water.
The reaction is similar, but not identical, to these from highschool chemistry.
Na (metal) + H2O -—> NaOH + H
Mg (metal) + HCl -—> MgCl + H [leaving out the 2’s]
With zirconium, it is
Zr + H20 -—> ZrO + H [Zr + 2H20 -—> ZrO2 + 2H2]
That is, Zr metal is converted to Zr-oxide, releasing hydrogen in the process. This does not occur at low temperatures. However, once started the reaction is exothermic, that is, it releases heat. Hence, it tends to get hotter, thus boiling away more water, and speeding up the release of more hydrogen. If nothing happens to get things cool, the process feeds on itself in a runaway fashion.
The problem is made worse by what is known as the “two phase problem.” That is, at the surface of the Zircaloy there is a mixture of liquid water, water vapor (steam), and hydrogen gas. The gases carry heat away poorly, and in effect they provide an insulating layer that hinders the liquid from effective cooling. And zirconium oxide is a much poorer conductor of heat than the metal, so the growing amount of ZrO2 further hinders heat transfer from the fuel rods. Hence, as time goes on, things get hotter.
The rods are about 3 meters long (10 ft), and the water bath normally covers them completely. In this loss of cooling scenario, they are not uncovered all at once. The water level slowly drops, exposing the upper parts of the rods, and the above applies basically to the circa 10-cm region around the water level; above is hot, below is cooler. But at this level, all is turbulent. And as the water level drops, this region keeps revealing new sections of the rods to the H-producing reaction. (The region above the turbulent interface is filled with very hot steam and previously released hydrogen, keeping the ZrO reaction going.)
Worser problems: The Zircaloy tubes (filled with uranium oxide pellets or some mix with plutonium) do not like this situation at all. They are much hotter than they can stand, they experience huge localized hot spots, a thermal gradient, the Zircaloy becomes soft, and the cladding is rapidly being converted to zirconium oxide (there are some other chemical reactions, too). The fuel rods then begin to swell, bend, balloon, buckle, get wart-like bubbles, and eventually develop holes. (The rods always have a fairly high internal pressure owing to the Xenon generated by the radioactive decay). The swelling and buckling may reduce the space between the rods, which then impairs the water circulation, leading to more super-hot spots. At an advanced stage, this becomes a runaway process with a total meltdown unstoppable and inevitable. The whole Pacific Ocean could not stop it.
The holes are what cause isotopes of cesium, xenon, iodine and other unsavory nucleotides to get released.
So far, it seems that only a few upper centimeters of the fuel rods have undergone this process, and only maybe two or three rods have developed holes (out of perhaps 50 rods—not sure of the total number). The concern is, if they have not been able to pump enough water in to prevent this level of Zr-hydrogen reaction, why won’t it get worse? The plant operators know everything—and more—than I have described, but they have not been able to get enough water into the reactor vessels.
The hydrogen problem, again, is that the water level is falling faster than they can pump it in (pump out hot water, replace with cool water). Water, water everywhere but not enough to cool.
Re: fuel rod fire in Unit 4 (emerging risk in Units 5 & 6)
Ok,I’ll be the jerk ... hate to post this because I don’t like the channel or the analyst ... but it is very informative.
Discussion on spent fuel rod cooling pools -
http://www.youtube.com/watch?v=RiXIODVlfXk
See especially: diagram at 8:02 and expert starting 10:30
Units 4,5,6 were “cold shutdown”, but the shutdown started in 6, then 5 and lastly 4. Lots of fuel rods (some old, some fairly new) are in large spent fuel cooling pools covered by 30+ feet of water. THERE IS MINIMAL CONTAINMENT FOR THIS FUEL ... just the water and the roof.
In Unit 4, the rods were still pretty hot, and the water had to be kept circulating to prevent boiling and loss of water level. When the station blackout occurred, the water level dropped. Ultimately the spent rods were exposed to the air, and the zirconium casing interacted with the oxygen to release hydrogen.
If *someone* does not get those “spent” fuel rods (in Units 4,5,6) covered with water, then any fire or rising smoke will be highly radioactive, and not contained if secondary containment is lost (as in Unit 4).
The fuel rods inside the reactor are much, much safer then those in the cooling ponds because of the primary metal and concrete containment.
Thanks for contributing a measure of sanity to this thread. Look, I know we all want to bash GE because of the current Obama connection but when the nuclear facilities were built in the early 70's, Jeffrey Immelt was all of 15 year old.
Yeah, I know all about how dangerous it is in reality. My buddy in Arizona told me the straight truth om Sunday and he used to work with nuclear power himself. Just wait and see what happens . . .
Zero Hedge reports a police vehicle with a water cannon has been brought in to try and water-down Unit #4. They are also (quickly) adding water to Units #5 & #6.
http://www.zerohedge.com/article/summary-update-japans-nuclear-crisis
That would seem to be a lot of steam - how come we don't see a constant steam plume?
Somebody linked this with eq stuff. It’s probably the cousin missing over here. Anyway, their plants no very safe. They are calling the workers at the plants on a suicide mission to stop the meltdown. Unfortunately, imo, their hard work and courage is in vain. They are giving their lives and it’s not working.
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