What’s Behind the Two Fukushima Explosions? Does Zirconium Explode at 2,000 Degrees?

So…what’s really behind the two Fukushima explosions? Were they hydrogen, or something else? You tell me, Dr. Fabulous. But here’s what I know, and here’s how an anti-nuclear activist just pissed me off by setting off my bullshit detector.

CommonDreams.org has a piece by Karl Grossman, journalism professor, anti-nuke activist and author of the 1980 book Cover Up: What You Are Not Supposed to Know About Nuclear Power, that is getting a lot of play in the wake of a second hydrogen explosion at the Fukushima I plant. It appears to have been written before the second explosion.

In this article, Grossman makes some claims about the element zirconium, used in the fuel cladding around the nuclear fuel, that set off my bullshit detector for no good reason. I don’t, or didn’t, know squat about zirconium or zircaloy. But his arguments sounded strange.

Here’s the background, as I understand it, summarized/repeated from my last post. Again, I’m not a chemist, but here’s what I gather. The matrix that holds the fuel rods in a nuclear reactor element is made of the element zirconium, as one of several alloys called zircaloy. At extreme heat, zirconium reacts with water and gives off oxygen, which is required for combustion, and hydrogen, which is flammable. That was the cause of the two explosions at Fukushima, according to the Japanese government. At Three Mile Island, a hydrogen bubble formed, but did not ignite.

Now here’s what Grossman said:

[T]here’s a huge problem with zirconium—it is highly volatile and when hot will explode spontaneously upon contact with air, water or steam.

The only other major commercial use of zirconium through the years has been in flashbulbs used in photography. A speck of it, on a flashbulb, ignites to provide a flash of light.

But in a nuclear plant, we’re not talking about specks—but tons and tons of zirconium, put together as a compound called “zircaloy” that clads tens of thousands of fuel rods.

Heat, a great deal of heat, builds up in a very short time with any interruption of coolant flow in a nuclear power plant—the problem at Fukushima after the earthquake that struck Japan.

Zirconium, with the explosive power, pound for pound, of nitroglycerine, will catch fire and explode at a temperature of 2,000 degrees Fahrenheit, well below the 5,000 degree temperature of a meltdown.

Before then, however, zirconium reacts to the heat by drawing oxygen from water and steam and letting off hydrogen, which itself can explode—and is said to have done so at Fukushima.

As a result of such a hydrogen explosion, there is additional heat—bringing the zirconium itself closer and closer to its explosive level.

Whether in addition to being a hydrogen explosion, zirconium also exploded at Fukushima remains to be known.

But what has happened regarding hydrogen at Fukushima, like the “hydrogen bubble” when the Three Mile Island plant in Pennsylvania underwent its near partial meltdown, is no mystery—but precisely what is expected in a loss-of-coolant accident.


I’m as skeptical of Grossman’s claims as I am of the guy who must be Grossman’s very best friend, atomic entrepreneur Rod Adams of the blog Atomic Insights and the company Adams Atomic Engines. (It turns out Adams doesn’t like Grossman much). I couldn’t ask for two nuclear advocates on opposite sides of the issue who make their agendas more screamingly obvious.

What set off my bullshit detector is Grossman’s claim that zirconium is dangerous because it’s used in old-school photo flashbulbs. Ever looked at a flashbulb? It has little wires in it, not zircaloy fuel cladding. My chemistry teacher built a flamethrower out of pastry flour and a ketchup bottle. Hey, do you think that must be why I no longer have a kitchen? I knew I shouldn’t bake bread! They also build racing wheels out of magnesium, which burns, and I’ve personally set aluminum foil on fire — but I wouldn’t want to stick a fuse in a 20 pound aluminum ingot and hurl it at a charging Cossack.

Secondly: “Zirconium, with the explosive power, pound for pound, of nitroglycerine, will catch fire and explode at a temperature of 2,000 degrees Fahrenheit.”

Zirconium explodes at 2,000 degrees Fahrenheit? The melting point is 3,371 degrees F. Run that by me one more time?

Don’t get me wrong — again, I’m just a caveman; I don’t know chemistry. I just finished reading a book about plutonium, and that stuff does some serious whack-ass shit. Other elements do strange things, too (though none so strange as plutonium). So I did not dismiss Grossman’s claims out of hand. Maybe solid zirconium really does explode.

But. When I search “zirconium explodes at 2,000 degrees,” the first four hits I get are Grossman articles, and a bunch of later ones are just people reposting Grossman’s quotes about it.  The next, a 2002 AOPA report on terrorist attacks, plane crashes and nuclear security, refutes his claim and says solid zirconium will not burn. Incidentally, page 2 is where the really whacked-out Bible Prophecy posts start.

Everywhere else I go, I find indications that zirconium powder or shavings will burn or explode. That’s what’s in old flash bulbs. NOT the solid zirconium (as zircaloy) that’s used in nuclear fuel cladding. The only stuff I find about solid zirconium or zircaloy exploding at 2,000 degrees comes from Grossman, or seems to be a refutation of Grossman’s claim (once in the AOPA report, once from a right-wing environmental blogger). I can’t find ANYTHING about Zirconium exploding at 2,000 degrees that didn’t originate with Grossman.

Grossman’s unreferenced statmenent that zirconium has the explosive power of nitroglycerine smelled from the start like a blatant appeal to fear, but hey, maybe it’s true. I just can’t find a directly credible reference for it, if it is.

Then Grossman commits an ethically questionable faux pas, in my mind, when he says: “Whether in addition to being a hydrogen explosion, zirconium also exploded at Fukushima remains to be known.”

That’s a classic dirty trick of argumentation. “Whether my esteemed opponent kicks puppies and hates Santa Claus, I don’t yet know.” Even if what he describes is physically possible, that’s not what NHK reported. He’s exaggerating the danger because he doesn’t like nuclear power. There’s no direct indication that the zirconium at Fukushima exploded.

Assuming zirconium really does explode at 2,000 degrees, could the Japanese government be lying by reporting it just as a hydrogen explosion? Could the Fukushima explosion have been a zirco-bomb? Of course. The Illuminati could also be planning to turn us all into cube steaks and feed us to Bigfoot on May 21, 2011; heck, you know, with everything I know about the government, “it wouldn’t surprise me.”

Both pro- and anti-nuke activists need to be careful that their competing agendas don’t imply things that aren’t supported by the available information. They also need to reference their facts. Spreading either fear or reassurance based on a political or financial agenda will just spread ignorance.

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5 comments on “What’s Behind the Two Fukushima Explosions? Does Zirconium Explode at 2,000 Degrees?
  1. I know you’ve referenced me as a “right wing environmental blogger” but if I could just point out that in my day job I deal with these sorts of exotic metals. Heck, I’ve even bought scrap zircalloy offcuts (non-radiated of course) and sent them off to be used in those MAG alloy car wheels (they use about 1% Zr as a grain refiner).

    I’ve also worked on making Zr powder to be used in car air bags.

    The technical phrase we’re looking for is “pyrophoric”. When a finely divided powder (or sometimes slices) is explosive, while ingots or solid pieces of the same material are not. Iron fines (a fine powder) are pyrophoric. Titanium powder, zirconium powder ditto. Yet we produce motlen iron in blast furnaces without it going band, we use titanium to make jet engines: and zircalloy does not explode either.

    As you note, flour is pyrophoric.

    Our journalism professor is speaking rectally.

  2. Tim — Thanks for the clarification; I looked at your bio to find out if your expertise was in metallurgy, and (no offense) couldn’t quite tell what it was saying.

    The statement that you’re the head of the international scandium oligopoly makes more sense now….I was bewildered by it on first reading. Not seeing (or not thinking I saw) a specific claim of “right-wing” from the first Amazon review of your book, so it was grabbed sort of off-the-cuff. Apologies if it’s not accurate.

    I’m about as far left as one can be, personally, but I think whack-ass claims either pro or con need to be challenged. Grossman’s claim about the fuel cladding had been repeated and repeated and repeated among my fellow lefties, within a matter of hours.

    Since he’s a journo, not a metallurgist, I’m guessing there’s some dubious reference he thinks he got it from. I would like to tack down that reference, so I can actually debunk the specific claim rather than just calling Grossman’s expertise into question.

  3. Tim, also, now that you mention it, I’ve seen iron filings set fire, too. If Grossman is confusing zirconium shavings and solid zircaloy, that is pretty egregious. I wanna find the origin of his claim so I can figure out WTF he thinks he’s talking about.

  4. Google zirconium reaction with water…..you can obtain some experimental data. Theoildrum.com has some discussion by chemists that have worked with Zr and water. Zr with steam in fairly hot conditions will produce hydrogen and Zr oxide. This seems to be a reaction that really takes off with increasing temperature. Hydrogen if pure will burn with almost a colorless flame, but mix in a little air ie oxygen and then boom. The zirconium cladding will disintegrate exposing the uranium. Since the radioactivity is such that helicopters will only fly down to 100 meters and start recording 80 millisieverts an hour, some of those zirconium tubes must have lot their integrity. Might be worth it to pick up a college chem text. Curtis

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