# Depleted Uranium ... shouldn't this violate some sort of treaty? **URL:** \ **Category:** Factual Questions\ **Created:** [June 12, 2000, 4:38pm UTC](https://boards.straightdope.com/t/depleted-uranium-shouldnt-this-violate-some-sort-of-treaty/22136 "2000-06-12T16:38:34Z")\ **Posts on this page:** 12\ **Page:** 2
**Author:** ![Whack-a-Mole](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/whack-a-mole/32/141_2.png) [@Whack-a-Mole](https://boards.straightdope.com/u/Whack-a-Mole)\ **Post date:** [June 13, 2000, 8:42pm UTC](https://boards.straightdope.com/t/depleted-uranium-shouldnt-this-violate-some-sort-of-treaty/22136/21 "2000-06-13T20:42:35Z")
> [@](#): > > One question: what is depleted uranium? I have the laymen’s definition of it, but I’m wondering, is it an isotope, or a mixture, or what? > [@](#): > > When U-235 (the highly fissionable isotope used to make bombs) is extracted from uranium ore, the remaining byproduct is U-238, uranium that has been “depleted” of its powerfully radioactive component. Source: [http://www.stats.org/newsletters/9803/du.htm](http://www.stats.org/newsletters/9803/du.htm) Basically DU is what’s left after they take the potent stuff out to make bombs. I don’t know about the characteristics of Uranium that would make it useful as armor. As a projectile it’s used for the same reason that lead is used. It’s HEAVY (i.e. very dense). Uranium is even more dense than lead which has been the traditional material for projectiles (bullets). The reason for this is simple…more weight equals more kinetic energy. You never see a ‘nickel’ bullet because it’s too light…not as much punch when it reaches the target (and also loss of accuracy…more easily affected by wind and what not). There are many requirements I imagine when choosing what to make armor out of. Density obviously can’t be too important or at least not the only consideration otherwise we’d see lead armor (but lead is too soft). Given that weight plays a role when deciding on how much armor to use it would seem that Uranium also may not be a good choice. But for all I know Uranium has fantastic charateristics making it ideal for armor or perhaps to create some super-alloy. I don’t know…just thinking out loud here. ---
**Author:** ![Spiny\_Norman](https://avatars.discourse-cdn.com/v4/letter/s/9de0a6/32.png) [@Spiny\_Norman](https://boards.straightdope.com/u/Spiny_Norman)\ **Post date:** [June 13, 2000, 9:32pm UTC](https://boards.straightdope.com/t/depleted-uranium-shouldnt-this-violate-some-sort-of-treaty/22136/22 "2000-06-13T21:32:41Z")
Copied from Carey Sublette’s excellent´Nuclear Weapons FAQ’, located at [http://www.fas.org/nuke/hew/Nwfaq/Nfaq0.html](http://www.fas.org/nuke/hew/Nwfaq/Nfaq0.html) > [@](#): > > When U-235 has been extracted from natural uranium, the remaining uranium is called “depleted uranium” because it has been depleted of U-235. Typically it still contains 0.25-0.4% U-235 since it is not economical to strip U-235 in concentrations this low (it is cheaper just to buy more natural uranium with higher concentrations). The U.S. tails concentration was 0.2531% in 1963, rising to 0.30% in the 70s. Due to the recent low cost of uranium, the trend has been toward higher tails concentrations in recent years. > > The U.S. has some 560,000 tonnes of depleted uranium hexafluoride (UF6) currently stored in cylinders at DOE’s three gaseous diffusion plant sites: Paducah, Kentucky; Portsmouth, Ohio; and Oak Ridge, Tennessee. (This is probably not the complete U.S. DU inventory.) > > Depleted uranium is about half as radioactive as natural uranium, almost entirely due to the removal of U-234, but its bulk properties are otherwise identical. Because the major use of uranium is for power production, depleted uranium is a waste product with little economic value. Finding uses for depleted uranium stockpiles has been a problem for enrichment plants. > > The uses it has found have generally been related to its great density and comparatively low cost. It two most important uses are as a radiation shielding material, and as balance weights in aerospace applications such as aircraft control surfaces, each Boeing 747 contains 1500 kg of DU for this purpose. It is used extensively in oil-well drilling in the form of sinker bars, weights used to lower instruments into mud-filled well holes. It has also been used in high-performance gyroscope rotors, large inertial energy-storage flywheels, and as ballast in ballastic missile reentry vehicles and racing yachts. > > Most famously, it is used in armor-piercing ammunition by the U.S… When suitably alloyed and heat treated (alloyed with 2% Mo or 0.75% Ti; rapid quenching for 850 C in oil or water, followed by aging at 450 deg. for 5 hrs) uranium is as hard and strong as hardened tool steel (tensile strength \>1600 MPa). Combined with its great density this makes it very effective at punching through armor, consistently superior to the much more expensive monocrystalline tungsten, it nearest competitor. The penetration process pulverizes much of the uranium, which explodes into burning fragments when it hits the air on the other side, adding to the destruction. Some 300 tonnes of depleted uranium were fired on the battlefield during Desert Storm (mostly from the GAU-8 30-mm guns of A-10 attack planes, each round contains 272 grams of DU alloy). It is also used in advanced armor, like that used on the M-1 Abrams tank. Racing yachts ? We can probably conclude that this is not an extreme radiological risk. (It’s used for radiation shielding, right ?) But obviously, it might be poisonous. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [June 13, 2000, 10:23pm UTC](https://boards.straightdope.com/t/depleted-uranium-shouldnt-this-violate-some-sort-of-treaty/22136/23 "2000-06-13T22:23:34Z")
Well, my back-of-the-envelope calculations say that U-238 is about a Curie a ton… Anyone have any data on safe exposure limits for humans, or for how much is used in the armor of a typical tank? Of course, most of the radiation from depleted uranium isn’t from the 238, it’s from the residual 235 that’s still in it, for which I don’t recall the half-life off the top of my head. Still, it’s undoubtable that the total radioactivity is significantly less than natural uranium, which isn’t even a controlled substance. ---
**Author:** ![bibliophage](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bibliophage/32/7615_2.png) [@bibliophage](https://boards.straightdope.com/u/bibliophage)\ **Post date:** [June 14, 2000, 5:13am UTC](https://boards.straightdope.com/t/depleted-uranium-shouldnt-this-violate-some-sort-of-treaty/22136/24 "2000-06-14T05:13:44Z")
The figures I have found vary (slightly different figures for different ores), but natural uranium has the approximate constituents[ul] .000055 [sup]234[/sup]U, t[sub]½[/sub] = 2.45 × 10[sup]5[/sup] .007200 [sup]235[/sup]U, t[sub]½[/sub] = 7.04 × 10[sup]8[/sup] .992745 [sup]238[/sup]U, t[sub]½[/sub] = 4.46 × 10[sup]9[/sup] [/ul] My estimate is that 238 and 234 each contribute about 48% of the radioactivity of natural uranium, and 235 only about 2%. This explains the quotation that **Spiny Norman** gave > [@](#): > > Depleted uranium is about half as radioactive as natural uranium, almost entirely due to the removal of U-234 **CRC Handbook of Chemistry and Physics** 74[sup]th[/sup] Edition\*\* says (p. **16** -33n.) > [@](#): > > A curie of natural uranium is here considered to correspond to 2.94 g. I don’t know how to square this with the ballpark estimate of disintegration rates for U-238 made by Chronos (about 1 Ci / ton) and my calculation (about 0.35 Ci / ton). ---
**Author:** ![Diceman](https://avatars.discourse-cdn.com/v4/letter/d/22d042/32.png) [@Diceman](https://boards.straightdope.com/u/Diceman)\ **Post date:** [June 14, 2000, 1:02pm UTC](https://boards.straightdope.com/t/depleted-uranium-shouldnt-this-violate-some-sort-of-treaty/22136/25 "2000-06-14T13:02:08Z")
Hmmm. I didn’t know that there were any stable isotopes of Uranium. Perhaps the stuff is fairly inert after all. Still, if DU shells can penetrate DU armor (as mentioned above) then the whole reason for having DU armor has been refuted, hasn’t it. And the GWS=Shell Shock=PTSS argument sounds pretty good to me. Still, according to the veterans webpages, the gov’t didn’t do much about _that_, either, so mayby they still have a right to bitch. Re: weight of armor. During the build-up to the Gulf War, a news report said that M1A1 tanks have a fuel efficiency of only 3/5 mpg! Any more DU armor, and they’ll need extension cords to run the damn things 😃 ---
**Author:** ![Boris\_B](https://avatars.discourse-cdn.com/v4/letter/b/fbc32d/32.png) [@Boris\_B](https://boards.straightdope.com/u/Boris_B)\ **Post date:** [June 14, 2000, 4:14pm UTC](https://boards.straightdope.com/t/depleted-uranium-shouldnt-this-violate-some-sort-of-treaty/22136/26 "2000-06-14T16:14:25Z")
**Diceman** said, > [@](#): > > Still, if DU shells can penetrate DU armor (as mentioned above) then the whole reason for having DU armor has been refuted, hasn’t it. I would say it hasn’t. No simple paper-defeats-rock analysis can have much validity hear. A DU round will be able to defeat armor at a greater range than a lead- or tungsten-core round. DU armor of a given thickness will (presumably) be able to defeat incoming rounds at closer ranges than steel, titanium, or composite armors. Nobody uses DU shells much, other than the U.S. (I don’t know of many non-US 30mm aircraft cannon either, as far as I know), so it might not really matter. I’m still not wholly sold on uranium as a building material. The laminated and composite armor sprees of the 70s and 80s were informed partly by Israeli experience in the Yom Kippur war. The same goes for the reactive armor phase. Now we have DU armor. To keep our tanks from being knocked out by…? T-85s, that we have outclassed pretty much from the start? Enemy aircraft that rarely come in effective anti-tank configurations? Land mines? NATO fire control is the best in the world. NATO airland thinking is much more advanced than most of our potential opponents. DU seems like a techno-happy incremental improvement in an area where we have an acceptable advantage (I don’t trust active armor, either). The U.S. will continue to win wars, because we have the largest tax base, the most technical expertise, and the best and most relevant allies (war in the Balkans: who do you want on your team - Germany or North Korea?) ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [June 14, 2000, 7:08pm UTC](https://boards.straightdope.com/t/depleted-uranium-shouldnt-this-violate-some-sort-of-treaty/22136/27 "2000-06-14T19:08:08Z")
Bibliophage: I think that all of the numbers can be reconciled. My estimate of the radioactivity of 238 was really only good to about an order of magnitude, so it squares with yours, a half-order lower. As to reconciling that with the CRC, they’re referring to natural uranium, not U-238. I think that the problem is in your estimate that the 238 contributes 2% of the total radioactivity… It should be a good bit less. Diceman, there aren’t any completely stable isotopes of uranium, but U-238 is awfully close-- Half-life of about 4 and a half gigayears. ---
**Author:** ![Grendel69](https://avatars.discourse-cdn.com/v4/letter/g/7bcc69/32.png) [@Grendel69](https://boards.straightdope.com/u/Grendel69)\ **Post date:** [June 14, 2000, 7:51pm UTC](https://boards.straightdope.com/t/depleted-uranium-shouldnt-this-violate-some-sort-of-treaty/22136/28 "2000-06-14T19:51:16Z")
Hey Diceman, as a civvie the one thing i noticed was the pollution caused by the oil wells burning. The oceans nearby had oil washing up on them for months and the rain (those few instances when it did) was greyish black. Has this been explored as a possible source for GWS? ---
**Author:** ![Gunslinger](https://avatars.discourse-cdn.com/v4/letter/g/4491bb/32.png) [@Gunslinger](https://boards.straightdope.com/u/Gunslinger)\ **Post date:** [June 14, 2000, 11:36pm UTC](https://boards.straightdope.com/t/depleted-uranium-shouldnt-this-violate-some-sort-of-treaty/22136/29 "2000-06-14T23:36:51Z")
I always thought that the “depleted” meant that it was, for lack of a better word, “un-radioactivated”. IOW, it’s not (as) radioactive (as nuke fuel-type uranium). ---
**Author:** ![JRDelirious](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jrdelirious/32/9531_2.png) [@JRDelirious](https://boards.straightdope.com/u/JRDelirious)\ **Post date:** [June 15, 2000, 2:34am UTC](https://boards.straightdope.com/t/depleted-uranium-shouldnt-this-violate-some-sort-of-treaty/22136/30 "2000-06-15T02:34:38Z")
I want to thank you all for this DU thread – recently around where I live there’s been a lot of mentioning of the stuff. Among the whole hoo-hah over the safety and further use of the Vieques Island Naval Range (which has a strong component that everyone suspects the Navy’s been dumping nasty stuff there) it came out that at some point in the late 80’s the Marines “mistakenly” fired off some 200 DU rounds, which were _not_ even authorized for training use at Vieques. Anyway, it looks to me as if the DU round would be a “natural” idea for the armies who had a heapin’ lot of uranium lying about from their countries’ nuke arms/energy programs. I wonder if the then-USSR deployed it, too? jrd ---
**Author:** ![kinoons](https://avatars.discourse-cdn.com/v4/letter/k/a698b9/32.png) [@kinoons](https://boards.straightdope.com/u/kinoons)\ **Post date:** [June 15, 2000, 4:32am UTC](https://boards.straightdope.com/t/depleted-uranium-shouldnt-this-violate-some-sort-of-treaty/22136/31 "2000-06-15T04:32:41Z")
Boris, The SU-25, the Soviet version of the A-10, packs a 30mm cannon. It isint the lead, um, DU, flinging 6 barrled gun that is on the A-10, but it is 30mm just the same ---
**Author:** ![Diceman](https://avatars.discourse-cdn.com/v4/letter/d/22d042/32.png) [@Diceman](https://boards.straightdope.com/u/Diceman)\ **Post date:** [June 15, 2000, 12:33pm UTC](https://boards.straightdope.com/t/depleted-uranium-shouldnt-this-violate-some-sort-of-treaty/22136/32 "2000-06-15T12:33:49Z")
> [@](#): > > \*\* > Hey Diceman, as a civvie the one thing i noticed was the pollution caused by the oil wells burning. The oceans nearby had oil washing up on them for months and the rain (those few instances when it did) was greyish black. Has this been explored as a possible source for GWS? > > \*\* Good point. I don’t know, but I’m sure environmental groups do. [Previous page](https://boards.straightdope.com/t/depleted-uranium-shouldnt-this-violate-some-sort-of-treaty/22136.md?page=1)