|Depleted Uranium Projectile.|
Within a few months of my starting to seriously collect elements nearly five years ago, it became clear that uranium was going to be a frustrating one. Though radioactive, uranium exists in vast quantities in stockpiles held by governments and industry, has various commercial applications, and is legal to own, at least in limited quantities. But just try to get some.
I was eventually able to acquire several very nice samples, but the one thing that continued to elude me year after year was a sample of what is no doubt the most common application by far of uranium: A depleted uranium projectile.
But no more! I was finally able to arrange a trade: 15 grams of thorium plus an undisclosed sum of money for one small, but indisputably genuine depleted uranium bullet. It's about 1/4" diameter, and is said to be an alloy containing 0.75% titanium to harden the material. The gold color comes from a plating of titanium nitride used to protect the surface from oxidation. This coating makes the object considerably safer to handle since there is no danger of uranium or uranium oxide rubbing off, as there is when handling bare uranium metal.
Natural uranium consists of a mixture of mostly U-238 (half life 4.5 billion years) and 0.72% of U-235 (half-life 700 million years, therefore considerably more radioactive than U-238). Depleted uranium is made by removing a fraction, usually less than half, of the U-235. This reduces the level of radioactivity of the material somewhat, and makes it totally unsuitable for any sort of bomb making. But it's still quite radioactive, emitting mainly alpha particles, plus small amounts of beta and gamma.
This little bullet reads tens of thousands of counts per minute using my mica-window Geiger counter, which is able to read alpha, beta, and gamma. (Most common meters read only beta and gamma.) You might think this makes the object rather dangerous, but the reason most meters don't read alpha emissions is that they are unable to penetrate anything, not even the outermost layer of dead cells on your skin. So as a solid, intact object, even quite large amounts of uranium are not particularly dangerous to be next to.
But break it up into a fine powder, for example by shooting it at something, and depleted uranium becomes very dangerous. Lodged in the lungs a spec of uranium can last for years, irradiating very sensitive living lung tissue the whole time.
This bullet was apparently an experimental design, and it's rather plain in comparison to some of the exotically shaped projectiles used in anti-tank munitions. Which is to say that, while I am absolutely ecstatic to finally be able to remove "depleted uranium projectile" from my most-wanted list, I am now forced to add "better depleted uranium projectile" to it.
Contributor: Theodore Gray
Acquired: 18 March, 2007
Text Updated: 19 March, 2007