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energy & nuclear | environment

Maybe no one does the math?

No expert, but just throwing this out there (because it bothers me greatly) and other thoughts for discussion...
OK. Maybe we as Americans are really intellectually challenged, or maybe the vast community of engineers and grade-school students (Grade school is where I learned the conversion formulas for temperature scales...) has just kept their mouths shut. But, here goes...

Tepco has said that the temperature of the rods in reactor no. 1 reached 2800 degrees celsius. So do the math...2800 x 1.8 + 32 = 5072 degrees farenheit. While either number (2800 or 5072) is well above the melting point of any steel alloy that I know of, and though that vessel is thick (I believe I've seen quoted a thickness of 7 inches; maybe thick, but at the quoted 16 hour exposure, not enough thickness to resist the temperature as it was assumed there would be little chance of total coolant loss for such time spans), how much is understood by the general public about metals, their alloys, and the effects of temperature? While we may take steel for granted (Iron, the principle chemical component in steel, is really the most useful and wonderful mettalic element used currently, and is unlikely to be supplanted by anything we can come up with soon. Think about it...Beside its abundance, in its alloys, like steel, it can be soft as butter, hard as a rock, formulated to bring out performance features and properties that would make a chameleon white with envy at the faces that steel can present to an engineer.) Steel, while basically carbon and iron, in the commonly encountered modern alloys it will have everything from aluminum to zirconium mixed in its makeup. We are very good at making these alloys, and they can be very predictable in their performance.

So steel, beside being an alloy of metallic and even non-metallic substances, is a chemical mixture, and subject to chemical reactions. Temperature is a great driver of chemical reactions...Hell, even the grain structure (the segregation and orientation of the crystal structure) of the material can greatly effect the susceptablity of a metal to chemical reaction, and these temperatures quoted will change grain structure. It's my guess (Being a metal-worker, and having had extensive exposure to a vast array of metals and their alloys, from common materials like steel to niobium, tantalum, zirconium, titanium and their alloys in everything from medical equipment to industrial heat exchangers and chemical process components...) that in conjunction with what may be melting is the liklihood of degradation of the steel alloy itself. For example, hydrogen, which is liberated through the chemical reactivity of hot zirconium with water, is VERY detrimental to steel or iron. It is common enough problem to have a industry-recognized name and consequences, hydrogen embrittlement, and is a function of temperature and exposure. (Zirconium, along with other materials, was for years and is still being used as a 'getter' of oxygen in vacuum tubes. That's the glowing red thing inside the tube, heated so that it will become chemically reactive and take up any stray atmosphere inside the tube to retain the vacuum; I instantly understood the hydrogen explosions as a consequence of the zirconium-water reaction.) Also an issue at these temperatures is the integrity of the alloy of the vessel itself. While the alloy is intact expected performance is predictable, alloys can lose what is assumed to be their homogenous mixtures and hence their exploitable properties. Alloys can, too, be changed through the working and fabrication impacting a desired basic grain structure. (There was a worker in Japan who claimed, and it was published long before this accident, that there were flaws in one of the vessels at fabrication, and a repair that was suspect.) And, one last thing, these are old fabrications. There is ample example of vessel deterioration in these older reactors even WITHOUT the temperature and physical extremes to which Fukushima's vessels were subjected.

I'm not particularly saying that hydrogen embrittlement is the direct culprit in their guess of 'holes' in the reactor pressure vessel, but what I'm getting at is that while engineers may assume they know and understand the materials, and in actual practice at those temperatures and exposure their knowledge may be better than yours or mine, there's little they can reliably predict except that they have a mass of 'whatever' in concrete containments. Concrete itself is a product of chemical reactions. What will be the consequence of this mass of 'whatever' and the concrete? I read somewhere that there have been simulations...Maybe they know more than they let on, but they aren't being enlightening, seeming to prefer that we discusss phrases without relativity such as 'China Syndrome'.

As it is, I think that it's pretty obvious that there isn't anyone directly involved who isn't in 'reactive' mode, and that there is really no 'plan' that can be formulated, and they're winging it. Though the descriptions of the components of the territory may be understandable, the combination of those components creates a whole new world which may just elude our imagination.