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Grand Canyon Museum Had Buckets of Uranium Sitting Around for 18 Years

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Re: Grand Canyon Museum Had Buckets of Uranium Sitting Around for 18 Years

#21

Post by Terr_ »

sandwall wrote: post #20

As correctly pointed out by other readers, this is a non-issue and complete overreaction. All feeding into misconceptions and irrational fear of radiation. The "safety professional" was out of his depth and clearly undereducated about the risks of radiation and uranium ore in particular. Hence, the true risk of a "dirty bomb" -- is psychological, i.e. it would be a weapon of mass disruption (not destruction), triagin…

> Hence, the true risk of a "dirty bomb" -- is psychological

I imagine there are some radiation-sources which are harmless outside the body because the dead cells of your skin would easily absorb and block them, but would wreak havoc if they were ingested or inhaled as dust.

Sometimes this is presented as a question where you have three or four cookies, which emit things like alpha/beta/gamma radiation and possibly neutrons, and you have to decide which cookie to eat, which to put into your pocket, which to put in a lead box, etc.

Re: Grand Canyon Museum Had Buckets of Uranium Sitting Around for 18 Years

#22

Post by soy_comptroller »

trimbo wrote: post #11
ams6110 wrote: post #2

Pretty lacking on specifics. What was the actual radiation level measured? I would assume these were not buckets of pure uranium, but of uranium ore that is naturally all over the place in the West, and not terribly radioactive in its natural state.

From a screenshot at [1] * 800 mR/hr if you touched the ore * 280 mR/hr on the surface of the bucket (sealed) * "0 above background" if you were 5 ft away from the bucket * 2.5 mR/hr if you were touching the cabinet it was in [1] - https://www.azcentral.com/story/news/local/arizona/2019/02/1...

Time to whip out the XKCD radiation chart[1], which gives us measures around:

* One chest CT per hour for touching the ore (or about 9 hours touching the ore to reach your annual max dosge)

* One head CT per hour for touching the bucket

* nothing for 5ft away

* One chest XRay per hour touching the cabinet (less than a cross-country flight LA NYC)

[1] https://xkcd.com/radiation/

Re: Grand Canyon Museum Had Buckets of Uranium Sitting Around for 18 Years

#23

Post by sandwall »

gotocake wrote: post #12
trimbo wrote: post #11

Earlier quoted context omitted.

From a screenshot at [1] * 800 mR/hr if you touched the ore * 280 mR/hr on the surface of the bucket (sealed) * "0 above background" if you were 5 ft away from the bucket * 2.5 mR/hr if you were touching the cabinet it was in [1] - https://www.azcentral.com/story/news/local/arizona/2019/02/1...

Basically unless you were having a very prolonged and loving relationship with the bucket, you were exposed to nothing of consequence. That doesn’t excuse the morons who kept this stuff, and if a kid took a souvenir home or there had been a fire it could have been a lot worse. They may have also had unacceptable levels of radon. If I worked there I’d want to know more, but just as a visitor I’d shrug and get on with…

Roentgens are historical units of exposure, it's simply what a lot of older meters read.

Roentgens can be assumed to safely equal RADs (although they don't, conversion is less than 1 for kV), the historical unit for "Radiation Absorbed Dose." For photons this would be equal to REM "Radiation Equivalent Man."

All old units; conversion to S.I., 100 rad = 1 Gray (J/Kg), 100 rem = 1 Sievert.

Essentially, who ever wrote the report was old and conservative.

The occupational risk is also essentially nil. This is much ado about nada.

Re: Grand Canyon Museum Had Buckets of Uranium Sitting Around for 18 Years

#24

Post by [deleted] »

tinus_hn wrote: post #14
kevin_b_er wrote: post #10

Earlier quoted context omitted.

* 800 mR/hr if you physically touched the rocks * 280-320 mR/hr if you physically touched the bucket(s) * 13.9 mR/hr if you were within 5 ft * 1.85 mR/hr inside the building more than 5 feet away. Also can be thought of as "0 mR/hr above background" * 2.02 mR/hr outside, in the park, on a bright sunny day. 2.02 is "background". i.e. the levels everyone is getting from natural sources outside. 13.9 mR/hr is 139 micros…

You do get a lot more exposure if you’re working at the museum every day though.

[deleted]

Re: Grand Canyon Museum Had Buckets of Uranium Sitting Around for 18 Years

#25

Post by js2 »

Discussed yesterday:

https://news.ycombinator.com/item?id=19195087

Not nearly as interesting as the radioactive boyscout story:

https://harpers.org/archive/1998/11/the-radioactive-boy-scou...

David Hahn sadly passed away at 39:

https://arstechnica.com/science/2016/11/this-fall-the-radioa...

Re: Grand Canyon Museum Had Buckets of Uranium Sitting Around for 18 Years

#26

Post by car »

ratsbane wrote: post #16

Which takes me back to a shower thought I had a long time ago: How do you know you don't need a geiger counter unless you have one?

I had the same thought, and wanted to check some strange ore from the desert. Eventually I soldered my own Geiger counter, thanks to the fabulous Safecast project. This is it: https://blog.safecast.org/bgeigie-nano/

It cost ~$650, but that's because it uses a very high-end geiger tube, and can detect alpha and beta in addition to gamma radiation. Comparable commercial devices do apparently cost a couple thousand.

Low and behold, the desert rocks weren't radioactive. However, taking the counter on an airplane was quite shocking, and gave the cabin crew real concern.

Re: Grand Canyon Museum Had Buckets of Uranium Sitting Around for 18 Years

#27

Post by [deleted] »

Terr_ wrote: post #21
sandwall wrote: post #20

As correctly pointed out by other readers, this is a non-issue and complete overreaction. All feeding into misconceptions and irrational fear of radiation. The "safety professional" was out of his depth and clearly undereducated about the risks of radiation and uranium ore in particular. Hence, the true risk of a "dirty bomb" -- is psychological, i.e. it would be a weapon of mass disruption (not destruction), triagin…

> Hence, the true risk of a "dirty bomb" -- is psychological I imagine there are some radiation-sources which are harmless outside the body because the dead cells of your skin would easily absorb and block them, but would wreak havoc if they were ingested or inhaled as dust. Sometimes this is presented as a question where you have three or four cookies, which emit things like alpha/beta/gamma radiation and possibly n…

[deleted]

Re: Grand Canyon Museum Had Buckets of Uranium Sitting Around for 18 Years

#28

Post by mehrdadn »

soy_comptroller wrote: post #22
trimbo wrote: post #11

Earlier quoted context omitted.

From a screenshot at [1] * 800 mR/hr if you touched the ore * 280 mR/hr on the surface of the bucket (sealed) * "0 above background" if you were 5 ft away from the bucket * 2.5 mR/hr if you were touching the cabinet it was in [1] - https://www.azcentral.com/story/news/local/arizona/2019/02/1...

Time to whip out the XKCD radiation chart[1], which gives us measures around: * One chest CT per hour for touching the ore (or about 9 hours touching the ore to reach your annual max dosge) * One head CT per hour for touching the bucket * nothing for 5ft away * One chest XRay per hour touching the cabinet (less than a cross-country flight LA NYC) [1] https://xkcd.com/radiation/

I've seen this chart and yet it's always fascinating.

A dental X-ray is like eating 50 bananas, and half of what you would get over the course of a normal day.

Re: Grand Canyon Museum Had Buckets of Uranium Sitting Around for 18 Years

#29

Post by sandwall »

pfdietz wrote: post #15
jhayward wrote: post #9

Earlier quoted context omitted.

The radiation hormesis theory[1] isn't widely accepted and shouldn't be used as a policy mechanism until there is much more known about its legitimacy and limitations. [1] https://en.wikipedia.org/wiki/Radiation_hormesis

Also, if one abandons the idea that dose response is linear, there is the possibility that the slope is even larger in the low dose regime than LNT would predict. The conservative approach would then be to adopt stricter limits, not looser ones.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6043938/
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