Grand Canyon tourists exposed for years to radiation in museum building | Hacker News Reader

Grand Canyon tourists exposed for years to radiation in museum building

azcentral.com

42 pointsSirLJ10 comments

On one hand this is criminal, stupid, and potentially dangerous behavior. If someone were directly exposed in such a way that they inhaled or swallowed some of the material their exposure could be very damaging. On the other hand this article uses a lot of comparisons between allowed safe exposure and this exposure, without an absolute metric to work with. From the picture with the estimated doses you’d get, were not talking about anything visitors should be concerned about.

If you were in direct contact with the contents of a bucket for an hour your total dose would be 8.2mSv. A more realistic hour in contact with the exterior of one of the buckets yields 2.8mSv. At five feet away from a bucket you’d get... nothing st all. For a visitor, this is not a problem although it’s also not ideal. You’re getting the equivalent of a full-body CT scan in the former case, but I somehow doubt anyone opened these buckets up and hugged the contents for an hour.

For reference 50mSv is the yearly acceptable exposure for nuclear plant workers, and someone working at this museum could have easily exceeded that if the contents of a bucket were disseminated in some way. In the absence of the contents being inhaled or eaten though, this isn’t a health risk. Stupid though... really stupid.

Before you get on your high horse, you should realize that this is unlikely to be a real emergency. Uranium ore is around an order of magnitude more radioactive than bananas. These officials appear to be overreacting and you seem to be going along with it without evidence. Chemical hazards are much more of a concern if it's not encased in a sealed exhibit. That to me is "really stupid."

I don’t think you actually read what I wrote, because you’re more or less just repeating my point while telling me to “get off my high horse.” I’d suggest responding to what people actually said, especially if you’re going to be rude to make your “point.”

For your reference:

From the picture with the estimated doses you’d get, were not talking about anything visitors should be concerned about... In the absence of the contents being inhaled or eaten though, this isn’t a health risk. Stupid though... really stupid.

Most of the radioactivity from uranium ore comes from radium impurities, and radium decays to radon, a gas. So, yes, it's entirely plausible for there to have been in an inhalation hazard. Though if anyone should be concerned it's the staff, not the tourists.

I'm confused. If the stuff in the buckets really was just uranium ore, even if it was really rich, then the only significant radiation was alpha, which would be completely undetectable (and not hazardous) outside the buckets. Am I missing something?

Uranium decays to radium which decays to radon, a gas. The real danger to uranium ore is inhaling radon. Also, the staff should be much more concerned than any tourist. The tourist angle seems sensationalistic, and a lost opportunity for informing the public about the dangers of radon.

unitednuclear.com sells uranium ore in addition to more exciting radioactive elements, and they have (had?) a page somewhere describing the need for good ventilation anywhere you store more than a small sample of ore.

EDIT: Maybe I was thinking of the product page for their radon gas detector, http://unitednuclear.com/index.php?main_page=product_info&pr...

  We purchased one of these detectors for ourselves and put in
  in the room where we stored our Uranium ore samples. The
  device indicated over 100 pCi/L ! For reference, the average
  indoor reading is 2pCi/L... at a reading of 100 pCi/L,
  immediate evacuation is called for.

  ...

  Since we do sell Uranium ore samples, it's important that we
  stress a point. Collecting and storing a few Uranium ore
  samples is not going to create dangerous levels of Radon gas
  in your home. However, if you are and avid collector, and
  you have several pounds of Uranium ore in your home, you'd
  should consider buying one.

Interesting, thank you. I didn't know radon was created that quickly.

The article mentions that the ore was discovered by chance by a young man with a geiger counter. Maybe it was the actually the radon he detected?

The decay chain to radon is slow, but the ore itself already has plenty of the intermediate products, including significant amounts of the immediate precursor radium, as its been sitting around for billions of years. AFAIU most of the measurable radiation from uranium ore comes from radium decay, so, yes, I assume what he was detecting was the decay chain starting from radium to radon.

The half-life of radon is very short (a few days), but that's part of what makes it so dangerous, along with being a gas and the fact that radon decay is itself highly energetic regardless of the half-life.

You can see the decay chain here: https://en.wikipedia.org/wiki/Uranium-238#Radium_series_(or_... The whole radon decay chain (radon->polonium->lead) happens quickly and is the most energetic part of the uranium decay chain. And because you can easily inhale radon, it can all occur inside your lungs where even alpha particles (especially alpha particles, actually) can damage cells. Basically, a lot of energy released in a very short amount of time within unprotected tissue. So while uranium ore may emit only a tiny amount of radon, radon itself is nasty enough that you can inadvertently go from harmless to potentially harmful by storing more than a handful of uranium ore in a confined space.

I'm not doing the actual science justice and perhaps mincing terminology (not my field), but that decay table should speak for itself.

If uranium ore is only 10x as radioactive as bananas, then could you make bombs from 10x the fruit? Seems easier than mining.

Even better, If you can turn potasium into uranium you will be rich (or killed, or both), but this is bananas.

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