Friday, December 13, 2013

Element of the Month: Plutonium!

December's Element of the Month:


Atomic Mass: 244ish amu
Melting Point: 639.4 °C
Boiling Point: 3228 °C

I have always thought of Plutonium as being more or less the non plus ultra of dangerous stuff. This might be due to its use in gadgets that, if used properly, can incinerate entire cities and all their inhabitants in a hellish explosive firestorm. I’ll stand by that logic. However, it turns out that Plutonium qua Plutonium is not nearly as bad as I thought! I mean, granted, it’s a highly radioactive material that has an unpleasant tendency to burst into flame if exposed to air, which isn’t good. And although it doesn’t lodge easily in the body, once it’s there it tends to nestle in unpleasantly in the bones and liver, where, well, it certainly isn’t good for you.

But then, it’s not necessarily lethal in tiny doses, either, and the proof of this is that you are reading this, despite having a handful of plutonium atoms lodged in your own bones and liver. Yes, I’m talking to you. You don’t carry a lot of Plutonium atoms around, mind you, but you almost certainly pack a few, just from sharing the atmosphere that was used for the hundreds and hundreds of tests that had to be done on the nightmarish explosive firestorm gadgets to make sure they would work properly when they were really needed. In one of these tests, the one that famously rendered Bikini Atoll uninhabitable, a series of blunders led to thousands of sailors being exposed to lots, lots more Plutonium then you ever have been. Those guys ended up having an average life span three months shorter than a control group, which is pretty nasty but nowhere near as bad as I would have expected.

Pure Plutonium, as used in an atomic weapon.  The ring shape spreads out
the material over a greater volume, which helps prevent premature
fission.  It's a safety feature.
Of course, I’m a little jaded from some of the more explicitly fakey elements we’ve looked at. Consider Bohrium for a moment. No, really: consider it. With a half-life of 61 seconds it is, shall we say, quite aggressively radioactive. While with Plutonium, we’re talking about a half-life of years: fourteen years for the least stable isotope, and up to 80 million years for the most stable. Compared to Bohrium, you almost want to make children's toys out of the stuff, except for its proclivity for bursting into flame at room temperature. Shattering, and bursting into flame.

There’s a smidge of naturally occurring Plutonium in the very richest Uranium ores, but for practical purposes the stuff was first cooked up by the University of California Bears in 1940. This should have led to some extremely tenure-worthy publication, of course, and the research team must have been devastated when their paper was yanked due to suspicions that the new element might have military applications. This turned out to be true, and it was not until 1946 that their research saw the public light of day. Neptunium (Element 93) and Plutonium (Element 94) were named by extrapolation from Uranium, this all having happened when disgraced former planet Pluto still had the wool over everyone’s eyes. The research team’s leader, Glen Seaborg, apparently also vetted “Ultimium” in the belief that he had found the last possible element. Seaborg was only 28 at the time – kids grew up faster during the Depression – and would live to see Element 106 named after himself in 1997.

Plutonium is a silvery-grey metal, quite radioactive and difficult to handle, and regardless of anything said above is not at all appropriate for use in children’s toys. There is probably between 500 and 1000 tons of the stuff in use and storage around the planet today, but it is all kept safely under lock and key.

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