# What is, exactly, is "Depleted Uranium?" **URL:** \ **Category:** Factual Questions\ **Created:** [September 16, 2011, 11:25pm UTC](https://boards.straightdope.com/t/what-is-exactly-is-depleted-uranium/596569 "2011-09-16T23:25:10Z")\ **Posts on this page:** 20\ **Page:** 2
**Author:** ![Bear\_Nenno](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bear_nenno/32/3358_2.png) [@Bear\_Nenno](https://boards.straightdope.com/u/Bear_Nenno)\ **Post date:** [September 17, 2011, 7:21pm UTC](https://boards.straightdope.com/t/what-is-exactly-is-depleted-uranium/596569/21 "2011-09-17T19:21:11Z")
> [@AK84](#): > > Not saying that **Bear\_Nenno** is wrong; but could someone clarify this. I remember when this was a big issue about 10 years ago; this was mentioned and NATO claimed that there was no risk; but they did start screening soldiers. Which part requires clarification? ---
**Author:** ![Bear\_Nenno](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bear_nenno/32/3358_2.png) [@Bear\_Nenno](https://boards.straightdope.com/u/Bear_Nenno)\ **Post date:** [September 17, 2011, 7:36pm UTC](https://boards.straightdope.com/t/what-is-exactly-is-depleted-uranium/596569/22 "2011-09-17T19:36:56Z")
From the US Army Combat Readiness/Safety Center- COMMON TASK 031-503-1017: Respond to Depleted Uranium “E. A final situation in which DU could present a hazard is if you are near (within 50 meters of) actively burning fires involving DU. If DU rounds are in a burning vehicle or otherwise exposed to an active fire, they form particles that can become carried by the smoke or settle in and around the vehicle.” [https://safety.army.mil/LinkClick.aspx?fileticket=rY7O5BSauzk%3D&tabid=652](https://safety.army.mil/LinkClick.aspx?fileticket=rY7O5BSauzk%3D&tabid=652) ---
**Author:** ![BigT](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bigt/32/12044_2.png) [@BigT](https://boards.straightdope.com/u/BigT)\ **Post date:** [September 18, 2011, 10:23am UTC](https://boards.straightdope.com/t/what-is-exactly-is-depleted-uranium/596569/23 "2011-09-18T10:23:20Z")
Isn’t Uranium 238 still useful if it’s converted to plutonium by bombarding it with a couple neutrons (it would shed two electrons)? I remember reading about this a long time ago, and that this discovery was very important because it meant that more uranium could be used. (Perhaps it was only one neutron and neptunium, or it somehow lost two electrons with only one neutron added.) Is that perhaps what happens in the third stage mentioned above? ---
**Author:** ![beowulff](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/beowulff/32/542_2.png) [@beowulff](https://boards.straightdope.com/u/beowulff)\ **Post date:** [September 18, 2011, 1:25pm UTC](https://boards.straightdope.com/t/what-is-exactly-is-depleted-uranium/596569/24 "2011-09-18T13:25:06Z")
> [@BigT](#): > > Isn’t Uranium 238 still useful if it’s converted to plutonium by bombarding it with a couple neutrons (it would shed two electrons)? I remember reading about this a long time ago, and that this discovery was very important because it meant that more uranium could be used. (Perhaps it was only one neutron and neptunium, or it somehow lost two electrons with only one neutron added.) > > Is that perhaps what happens in the third stage mentioned above? This is what called “breeding” fuel. Currently, there are no plans to build breeder reactors, because of weapons proliferation concerns. But, it would certainly stretch the world’s supply of fissionable materials. This is NOT what happens in an H-Bomb. In that case, the U-238 tamper / reflector undergoes “fast fission” where a single high-energy neutron causes the atom to fission. The neutrons released during a standard U-235 chain reaction are generally not fast enough to cause U-238 to fission, but there are plenty of fast neutrons released during fusion, so U-238 can be used to boost yield. Also makes the bomb really, really dirty. ---
**Author:** ![Mr.Skinny](https://avatars.discourse-cdn.com/v4/letter/m/3be4f8/32.png) [@Mr.Skinny](https://boards.straightdope.com/u/Mr.Skinny)\ **Post date:** [September 18, 2011, 6:27pm UTC](https://boards.straightdope.com/t/what-is-exactly-is-depleted-uranium/596569/25 "2011-09-18T18:27:45Z")
> [@Chronos](#): > > Well, yes, of course, but it’ll still click on a Geiger counter. And what radioactivity it does have is mostly alpha particles, which are the worst kind if the material is inside of you (eaten or inhaled). 😕 So inhaling or ingesting an alpha emitter is worse than inhaling or ingesting a beta or gamma emitter? ---
**Author:** ![FXMastermind](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/fxmastermind/32/7289_2.png) [@FXMastermind](https://boards.straightdope.com/u/FXMastermind)\ **Post date:** [September 18, 2011, 6:46pm UTC](https://boards.straightdope.com/t/what-is-exactly-is-depleted-uranium/596569/26 "2011-09-18T18:46:50Z")
> [@Jake](#): > > What is it used for? Where does it come from? It comes from the waste created when people make Enriched Uranium, which is used as fuel for nuclear reactors. Unless you are lacking a reactor to make Plutonium, nobody makes a bomb from Enriched Uranium. Plutonium is much better for bombs. The uranium is usually enriched to 2.5-3.5% U-235 for reactor fuel. To make a bomb you need to enrich it to over 90%, which is a bitch, so again, nobody is using Enriched Uranium to make bombs. > **[Enriched uranium](https://en.wikipedia.org/wiki/Enriched_uranium)** > > Enriched uranium is a type of uranium in which the percent composition of uranium-235 (written 235U) has been increased through the process of isotope separation. Naturally occurring uranium is composed of three major isotopes: uranium-238 (238U with 99.2732–99.2752% natural abundance), uranium-235 (235U, 0.7198–0.7210%), and uranium-234 (234U, 0.0049–0.0059%). 235U is the only nuclide existing in nature (in any appreciable amount) that is fissile with thermal neutrons. Enriched uranium is a c... Each reactor needs around 150 tons of Enriched Uranium a year to run, so there is a LOT of depleted Uranium left over after they extract the U-235 for fuel. Well, a lot if you count the mass, it’s not very much if you consider a 100 Kilo ball of depleted Uranium is not much bigger than a softball. Maybe, that is classified information. Forget I said anything. So the source of DU is nuclear fuel enrichment. Man I hope this doesn’t turn into a nuclear power thread. ---
**Author:** ![Jake](https://avatars.discourse-cdn.com/v4/letter/j/f475e1/32.png) [@Jake](https://boards.straightdope.com/u/Jake)\ **Post date:** [September 18, 2011, 7:11pm UTC](https://boards.straightdope.com/t/what-is-exactly-is-depleted-uranium/596569/27 "2011-09-18T19:11:53Z")
I do too, **FX**. Thanks to everyone for your responses! ---
**Author:** ![running\_coach](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/running_coach/32/15836_2.png) [@running\_coach](https://boards.straightdope.com/u/running_coach)\ **Post date:** [September 18, 2011, 7:23pm UTC](https://boards.straightdope.com/t/what-is-exactly-is-depleted-uranium/596569/28 "2011-09-18T19:23:10Z")
> [@FXMastermind](#): > > Each reactor needs around 150 tons of Enriched Uranium a year to run, so there is a LOT of depleted Uranium left over after they extract the U-235 for fuel. Well, a lot if you count the mass, it’s not very much if you consider a 100 Kilo ball of depleted Uranium is not much bigger than a softball. Maybe, that is classified information. Forget I said anything. A softball has a volume of 334 cc. 6.35 kg. ---
**Author:** ![Dahu](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dahu/32/3416_2.png) [@Dahu](https://boards.straightdope.com/u/Dahu)\ **Post date:** [September 18, 2011, 7:35pm UTC](https://boards.straightdope.com/t/what-is-exactly-is-depleted-uranium/596569/29 "2011-09-18T19:35:31Z")
> [@cmyk](#): > > …since \*U238 \*contains a very small amount of U235… Just a nitpick - I think you mean _natural uranium_ contains a very amount of U235. By definition, U238 contains nothing except U238. ---
**Author:** ![beowulff](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/beowulff/32/542_2.png) [@beowulff](https://boards.straightdope.com/u/beowulff)\ **Post date:** [September 18, 2011, 7:50pm UTC](https://boards.straightdope.com/t/what-is-exactly-is-depleted-uranium/596569/30 "2011-09-18T19:50:04Z")
> [@Mr.Skinny](#): > > 😕 > > So inhaling or ingesting an alpha emitter is worse than inhaling or ingesting a beta or gamma emitter? Yes. Alpha particles are relatively massive, so they don’t penetrate very far, but this means that they deliver all of their energy in a very small area, resulting in massive cell destruction in that area. ---
**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:** [September 18, 2011, 8:09pm UTC](https://boards.straightdope.com/t/what-is-exactly-is-depleted-uranium/596569/31 "2011-09-18T20:09:38Z")
Yeah, if an alpha source is _outside_ you, it’s pretty much harmless, since the alphas will mostly be stopped by your clothes or even the dead outer layers of your skin. If it’s inside you, though, they’re being stopped by your innards, which is not a good thing. By contrast, betas and gammas can penetrate clothing and skin, and so can harm you from outside, but they’re also likely to penetrate all the rest of you, too, and thus end up doing nothing much to you, even if they started off inside you. ---
**Author:** ![FXMastermind](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/fxmastermind/32/7289_2.png) [@FXMastermind](https://boards.straightdope.com/u/FXMastermind)\ **Post date:** [September 18, 2011, 8:54pm UTC](https://boards.straightdope.com/t/what-is-exactly-is-depleted-uranium/596569/32 "2011-09-18T20:54:56Z")
FYI it only takes 10 pounds of Plutonium (Pu-239) to make a hydrogen bomb (capable of destroying New York City) but it would take 33 pounds of U-235 to get the same bang. ---
**Author:** ![FXMastermind](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/fxmastermind/32/7289_2.png) [@FXMastermind](https://boards.straightdope.com/u/FXMastermind)\ **Post date:** [September 18, 2011, 9:12pm UTC](https://boards.straightdope.com/t/what-is-exactly-is-depleted-uranium/596569/33 "2011-09-18T21:12:13Z")
> [@runner pat](#): > > A softball has a volume of 334 cc. 6.35 kg. A softball of Plutonium would be 6,546.4 grams. Or 65.4 Kg or 144 pounds Hmmm, yep, not much bigger than a softball. Oh crap, I was talking about Uranium. A softball of Uranium would be 63.8 kg. A 100 kg would be a little bigger than a softball. Wait, what was the point? ---
**Author:** ![user\_hostile](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/user_hostile/32/474_2.png) [@user\_hostile](https://boards.straightdope.com/u/user_hostile)\ **Post date:** [September 18, 2011, 10:34pm UTC](https://boards.straightdope.com/t/what-is-exactly-is-depleted-uranium/596569/34 "2011-09-18T22:34:53Z")
> [@FXMastermind](#): > > FYI it only takes 10 pounds of Plutonium (Pu-239) to make a hydrogen bomb (capable of destroying New York City) but it would take 33 pounds of U-235 to get the same bang. \ As a trigger for a hydrogen bomb \< itpick\> ---
**Author:** ![running\_coach](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/running_coach/32/15836_2.png) [@running\_coach](https://boards.straightdope.com/u/running_coach)\ **Post date:** [September 18, 2011, 10:49pm UTC](https://boards.straightdope.com/t/what-is-exactly-is-depleted-uranium/596569/35 "2011-09-18T22:49:12Z")
> [@FXMastermind](#): > > A softball of Plutonium would be 6,546.4 grams. Or 65.4 Kg or 144 pounds > > Hmmm, yep, not much bigger than a softball. > > Oh crap, I was talking about Uranium. A softball of Uranium would be 63.8 kg. A 100 kg would be a little bigger than a softball. > > Wait, what was the point? 1 **KILO** gram= **1000** grams. ---
**Author:** ![FXMastermind](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/fxmastermind/32/7289_2.png) [@FXMastermind](https://boards.straightdope.com/u/FXMastermind)\ **Post date:** [September 18, 2011, 10:55pm UTC](https://boards.straightdope.com/t/what-is-exactly-is-depleted-uranium/596569/36 "2011-09-18T22:55:51Z")
I thought there was something wrong with those figures. This is why it’s classified. ---
**Author:** ![user\_hostile](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/user_hostile/32/474_2.png) [@user\_hostile](https://boards.straightdope.com/u/user_hostile)\ **Post date:** [September 19, 2011, 12:17am UTC](https://boards.straightdope.com/t/what-is-exactly-is-depleted-uranium/596569/37 "2011-09-19T00:17:09Z")
NM. ---
**Author:** ![cmyk](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cmyk/32/3353_2.png) [@cmyk](https://boards.straightdope.com/u/cmyk)\ **Post date:** [September 19, 2011, 12:54am UTC](https://boards.straightdope.com/t/what-is-exactly-is-depleted-uranium/596569/38 "2011-09-19T00:54:08Z")
Nuclear power is the bomb! ---
**Author:** ![FXMastermind](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/fxmastermind/32/7289_2.png) [@FXMastermind](https://boards.straightdope.com/u/FXMastermind)\ **Post date:** [September 19, 2011, 1:09am UTC](https://boards.straightdope.com/t/what-is-exactly-is-depleted-uranium/596569/39 "2011-09-19T01:09:01Z")
Plutonium actually is pretty awesome. ---
**Author:** ![Triskadecamus](https://avatars.discourse-cdn.com/v4/letter/t/b19c9b/32.png) [@Triskadecamus](https://boards.straightdope.com/u/Triskadecamus)\ **Post date:** [September 19, 2011, 2:24am UTC](https://boards.straightdope.com/t/what-is-exactly-is-depleted-uranium/596569/40 "2011-09-19T02:24:30Z")
Now days, how much fissile material it takes is more a matter of geometry, and timing. We are so far ahead of the massively wasteful methods used in most of our existing fission weapons that it very much pays us to disassemble them and reuse their material to make new weapons. Since our current technology deals with timing several orders of magnitude more accurate, and our theoretical models of explosive events are so much more accurate, we can create shaped explosions, and make the fissile material surrender far more than the trivial percentages that were released in the 1940’s The amount of Uranium was once a limiting factor in Nuclear Warfare. That is no longer the case. Newer bombs are adjustable in yield, same bomb; different explosive force. “Dial-a-bomb.” Our weapons programs and the people who run them have often assured Congress that we do not have, and are not designing suitcase bombs. If that is true, it is only because the weapons programs are entirely run by very ethical and highly motivated humanitarian minds. [Previous page](https://boards.straightdope.com/t/what-is-exactly-is-depleted-uranium/596569.md?page=1)