Depleted Uranium (DU) Update

February 12, 2003 4:20 PM

It's not just for bullets anymore! previously discussed on MeFi here, I would like to reconsider "Depleted Uranium" (DU) in terms of its non-military uses. As ballast in the Columbia, the pieces of which were scattered across our country, for instance? Also in the ballast of many commercial airplanes, helicopters and ships. Should we really be using this stuff so lightly? I mean, just because it's twice as heavy as lead does that counterbalance the incredibly damaging long-term (half-life = how many billion years?) effects of DU burning and becoming a wind-borne inhalant? (Gulf Syndrome) To paraphrase Seinfeld, what's the deal with DU?
posted by zekinskia (27 comments total)

mmm, beholder statues
posted by jcruelty at 4:28 PM on February 12, 2003

Depleted uranium burns? Or, just melts?
posted by mischief at 4:34 PM on February 12, 2003

mischief: it actually burns explosively on impact when used as ammunition. It's called "friction burn," and results in airborne "radioactive dust particles." I may be incorrect, but I would assume that when an airplane or space shuttle crashed, the frequently experienced combustion of jet or rocket fuel would produce similar results. Those dust particles, a result of the estimated 800 tons of DU U.S. and British ammo blown in Iraq and Kuwait, is, IMHO, a good candidate for the culprit behind Gulf War Syndrome, as they may remain airborne and respirable for quite a while in the desert climate, and then move into the water, vegetables, livestock, etc.
posted by zekinskia at 4:44 PM on February 12, 2003

we should put it in a rocket and shoot it at the sun.
posted by Hall at 4:49 PM on February 12, 2003

mmm, friction burn.
posted by hammurderer at 5:32 PM on February 12, 2003

How much of it oxidizes in the process? From what I can see, only the very outermost layer of DU burns as it penetrates armor, effectively causing the projectile to become sharper. Once it comes to rest, the DU appears to be substantially intact with very little loss.

(... and to think I was handling this stuff for years as a radiological effluents inspector for the Nuclear Regulatory Commission!)
posted by mischief at 5:45 PM on February 12, 2003

It's expensive to launch mass into space: more mass requires more fuel and limits payload. Why on earth, then, would a spacecraft have ballast of any sort?
posted by mcwetboy at 5:58 PM on February 12, 2003

DU emits alpha particles that can be blocked by a piece of paper. Think about it: DU is depleted of what? U-235--the stuff that goes boom. DU IS radioactive, but not very. You get exposed to more and more harmful celestial radiation living in Denver than you would if you put a DU shell in your living room.

Those birth defects in Iraq and Gulf War Syndrome are probably the results of exposure to chemical weapons.
posted by tholt at 6:10 PM on February 12, 2003

tholt, even alpha emitters can be dangerous when ingested in sufficient quantities. The questions here are what quantity is vaporized in these various processes, and how well is that then dispersed and at what concentration.
posted by mischief at 6:33 PM on February 12, 2003

tholt, even alpha emitters can be dangerous when ingested in sufficient quantities.

Mischief, so can twinkies.
posted by swerdloff at 6:53 PM on February 12, 2003

DU's extremely long halflife demonstrates that it is *very very barely* radioactive. If you're worried about that level of glowing stuff, then I suggest not traveling in an airplane (30,000 ft = more radiation), never going outside, not living in a stone house, etc. etc. etc.

As for Gulf War Syndrome... I'm betting that cordite and some of the other ammunition propellants have some very, very interesting gaseous by-products. Also, having all of the Kuwaiti oil fields on fire, emitting highly toxic smoke, probably wasn't a good thing.
posted by Ptrin at 7:09 PM on February 12, 2003

It makes really nice glass. I'd love to have some of it in my house, even if it means I have to house it in a lead glass case. :-)

Geiger counters away!
posted by shepd at 7:22 PM on February 12, 2003

Ohh, and speaking of radioactivity, how many of you that are deathly scared of it have smoke detectors?

Betcha didn't think most of you have radioactive devices in your homes. :-)

It's not even worth the effort trying to stop this stuff, considering that even a child can build a nuclear reactor, anyways.
posted by shepd at 7:26 PM on February 12, 2003

mischief: No, the question is how much radiation you might be able to absorb as the result of this kind of event, and the answer is, damn little. U238 --- the stuff that's left in DU --- has a half life of 4.51 billion years. That means it's not very radioactive. You'll be cold in the grave from old age before more than a minuscule fraction of that uranium can decay. This is basic freshman physics, guys.

Am I saying that DU is a perfectly safe material that we should all stir into our coffee? Of course not. But there are plenty[pdf] of other things worth being worried about. To a first approximation, the danger of DU[pdf] is the same as for other heavy metals, such as lead.

(And I'd like to echo mcwetboy's question: why would there be DU ballast on the shuttle? Is there any reason at all to think that there was?)
posted by hattifattener at 7:46 PM on February 12, 2003

I can see that I should start using sarcasm tags on this board.
posted by mischief at 8:42 PM on February 12, 2003

RE: DU dangers? -- There is a considerable body of recent research which suggests that, counterintuitively, "the dose is not the poison" - that low levels of toxicity (or radiation) can have significant or even worse effects than higher level doses. I'm too tired to look this up at the moment. Google yrrself if you care.
posted by troutfishing at 8:51 PM on February 12, 2003

DU might not be radioactive, but it is dangerours, as hattifattener said. Mcwetboy: I suppose they have to balance the shuttle somehow, as it carries different payloads.
posted by lazy-ville at 9:38 PM on February 12, 2003

I'm not a rocket scientist, nor do I play one on tv, but:

The shuttle's ballast is most likely to control its center of mass.

I for one would not be surprised to find that some of the ballast is movable in flight to reconfigure the COM from launch to disgorging the payload to reentry.

And I suspect that the reasonable alternatives as ballast or armor-penetrators, tungsten or other heavy metals, are roughly as toxic. Certainly heavy metals of all sorts are harmful to children and other living things.
posted by ROU_Xenophobe at 10:23 PM on February 12, 2003

I'm not really sure about labeling DU as dangerous. It's definitely something to be aware of and use appropriately, but I don't see it as any more dangerous than lead or other heavy metals.
posted by rudyfink at 10:24 PM on February 12, 2003

RE: DU dangers? -- There is a considerable body of recent research which suggests that, counterintuitively, "the dose is not the poison" - that low levels of toxicity (or radiation) can have significant or even worse effects than higher level doses. I'm too tired to look this up at the moment. Google yrrself if you care.

Can anybody back this up? It sounds like reverse homeopathy to me.
posted by obfusciatrist at 11:16 PM on February 12, 2003

troutfishing: please please tell me you're not referring to homeopathy.
posted by PenDevil at 11:26 PM on February 12, 2003

Perhaps troutfishing is referring to the possibility that a cell simply mutated by radiation is more likely to cause cancer than one killed and destroyed by it?

Not that I can back that up at all, but it's just my best guess.
posted by shepd at 11:50 PM on February 12, 2003

Depleted Uranium, is it harmful?
DU's low radioactivity means that it is handled with few safety precautions. The immediate health hazard from radioactivity is very small (smaller than, say, sunbathing), but problems arise when DU burns in air. The ash, made of uranium oxide, can form a fine powder which like all fine powders tends to get everywhere. If you breathe it in it will lodge deep in your lungs. And there, as far as we can tell, it will sit for the rest of your life. So now, 100 percent of the radiation is delivered direct to your lungs. Some people claim that over time this poses a serious health risk, especially of cancer, and there appears to be growing evidence to support such claims. Perhaps surprisingly, there is little published research on the subject.

It seems that a huge lump of DU just sitting there poses practically no risk- when it burns however it is indeed dangerous. It is elsewhere suggested that it is the chemical toxicity of the dust that is the real health hazard...
This is a pretty thorough review of DU radiation exposure issues. And this is a handy Uranium Radiation Individual Dose Calculator
posted by talos at 3:26 AM on February 13, 2003

Mischief, you will need to make your sarcasm tag in giant flaming red letters.
posted by Dick Paris at 3:33 AM on February 13, 2003

tholt, even alpha emitters can be dangerous when ingested in sufficient quantities.

Mischief, so can twinkies.

Actually, its more dangerous to ingest alpha and beta emitters than gamma emitters, alpha particles will be absorbed in the lung if a source breathed in, whereas gammas will largely pass through the body without nearly as much damage. This 'absorbed by a piece of a paper' thing is all very well, but lungs aren't paper lined.
See here for a simple explanation.
posted by biffa at 3:58 AM on February 13, 2003

IMHO, all hell is going to break out over DU in the very near future. I understand from a soldier friend that the tank corps have recently completed test firings of tungsten sabot (armour piercing) rounds.

Engineering firm, WS Atkins signed off an enviromwental impact assessment on DU following test firings at the Eskmeals and Dunrennan ranges. The firm's findings were positive and stated that there was little residual radiation found after test firings. Handling guidelines were written up but if the services are trying to phase out the material's use, I'm willing to bet that the current inquiry into DU is going to report in the near future and the report is likely to be condemnatory....
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