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Linda Z

Science question--Zixar? Anyone?

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I'm hoping Zixar or one of the other scientific brains on here can answer this for me. (Please don't laugh!)

In addition to the rocks I've accumulated over the years, I have an old souvenir-type rock "collection"--the kind sold at tourist traps in the 40s and 50s (and probably earlier), with samples of various rocks and minerals mounted and labeled on a piece of cardboard in a flat box.

Included is a piece of uranium. I don't know much about earth sciences, so please bear with me if this is a silly question: Does that piece of uranium pose any sort of a health risk to humans or small animals? It's small, only about an inch long by a half-inch across.

Thanks to anyone can help the geologically challenged!!

Linda

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Why, yes, indeed, it does.

If it is truly uranium.

I'm not sure what you should do with it, or where you should take it.

But radiation has a cumulative negative effect, if the source of the radiation is not removed.

Since you probably have it on display or in a closet, it's effects are lessened. You'd have to be within a few feet of it for hours at a time for the radiation to cause problems.

But I'd get rid of it if I were you, even though it's probably a fairly low-grade rock.

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Now I have to figure out what to do with it!

Damn, the stuff I buy at estate sales sometimes. It was a nostalgia thing. As a kid I used to hound my dad to buy me those little boxes of rocks while traveling out west. Never saw one before with uranium in it.

I wonder if it's possible that it was "deactivated" somehow. I just looked at the box again, and there's a sticker with a 7-digit phone number on it, so I doubt it's any earlier than the 50s. I'd think they'd have known better by then than to sell radioactive material!

I guess the good news is that, just in case, I have kept the lid on the box and have only looked in there a few times. (Am I glowing yet?}

If I really should get rid of it, we have a city number to call for disposal of hazardous materials. I guess maybe that would be the way to go, if they don't laugh me off the phone. I'm sure they're accustomed to dealing with chemicals and boxes of WWII bullets that people find while cleaning out their elderly fathers' garages.

Thanks again,

Linda

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Well, don't call the NRC yet. It's probably a sample of uranium ore (uraninite, pitchblende, or similar) and while it might elicit a tick or two from a geiger counter, odds are that the majority of the uranium in it is U-238 instead of the more active bomb material, U-235.

U-238 makes up over 99% of all the free uranium on Earth. It's a relatively stable atom, as fissionables go, having a half-life of about 4.5 billion years. It's primary decay mechanism is emission of helium nuclei, which we call alpha particles. A U-238 nucleus will spontaneously emit an alpha particle and turn itself into an atom of Thorium-234.

Alpha radiation is the least hazardous because it is the least energetic. It is easily shielded against, being stopped by a few sheets of paper, or your clothing. (It's beta and gamma radiation that you have to watch for, gamma especially.)

You are being pelted by more beta radiation from your monitor right now (electrons sneaking around the phosphor mask and hitting you in the face) than that little pebble puts out in an hour.

Remember the old glow-in-the-dark clocks? That was radium paint, which puts out a lot more radiation than your uranium does. Or your smoke detectors, which contain a speck of highly radioactive americium. You don't worry too much about those.

As long as it's in its box, and you don't swallow the thing, just keep it as a cold war souvenir.

God bless!

Zix

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Back in *79* I worked at a uranium strip mine and a brother-in-law worked in an underground uranium mine. The ore from mines is taken and milled to make yellow cake; it takes a half-ton of good quality ore to produce a single pound of yellow cake. Yellow cake was transported in 55 gal. barrels in trucks that had no special protection. We had key-chains with small glass jars containing yellowcake and the radiation couldn’t get out the glass.

The yellowcake was taken to another facility where once again a thousand pounds was refined to a single pound that was now usable uranium for powering nuclear power plants. That was when this stuff became concentrated enough to be harmful if proper protection wasn’t used.

In the underground mines the miners where patches that would change color when exposed to very low radiation. If a patch, which is more like a card clipped to clothing; changed color that area was evacuated and tested. In 20 years working right down in the ore, no ones patch ever changed.

Your little sample is as safe as any *Indian Sex Rock*

Grizzy COLOR>SIZE>

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when kids would find a pretty rock, parents often replied that.............

means just another *f'ing* rock

Grizzy COLOR>SIZE>

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Zixar doesn't need anyone to vouch for him, but he is right on.

It is only the "enriched" uranium that you need to worry about. They take the ore and fiddle with it to make it work better as fuel in a nuclear reactor. What you have is safe.

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It's U-235 that you need for fast-fission chain reactions. Either that, or plutonium-239. Since plutonium didn't exist on Earth until 1944, scientists had to extract the tiny fraction of U-235 from all the U-238 in order to make the first atomic pile, and the subsequent atom bombs. The good thing is, you can use some of the excess neutron flux from a U-235 fission pile to irradiate pellets of "depleted" uranium-238 and turn them into pellets of plutonium-239. (This is called a breeder reactor) Pu-239 works better than U-235 in power plants and nuclear weapons.

The other use for pure U-238 (the "depleted" stuff, from which the "hot/enriched" U-235 has been extracted) is for anti-tank bullets. Uranium is denser than lead, so it packs more of a punch. It is also pyrophoric, meaning it can ignite spontaneously upon contact with air. Depleted uranium bullets have a thin coating to keep them from pyrophorically igniting in the gun, or storage, but that coat doesn't survive the impact. The A-10 Warthog ground-attack aircraft has a 30mm cannon that fires these DU rounds, and is the best tank-buster going today.

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Jim emailed me and pointed out a couple of errors in my last post:

Plutonium was first syntehsized in 1941, not 1944, as I had stated, and it has been found naturally in at least two places.

Thanks, Jim!

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