[mlindner]

I wouldn't even call it bad. Reactor pools have basically zero radiation at the surface. The water is constantly filtered and kept very pure to remove contaminants that can be activated by neutrons.

Even drinking it I would think would be completely fine. The water itself doesn't get activated.

[happyopossum]

Then where did their radioactive hair come from?

[Brian_K_White]

That's what I was thinking, but it does look like 300 cpm for a few hours is essentially nothing, or it looks real bad, I can't tell.

I found this:

  Days to receive chronic dose for increase cancer risk of 1 in a 1,000
  432 (at 100 CPM)
  86 (at 500 CPM)

Ok so 300 for an hour (we'll assume the hair is cut off and the exposure either stops or 90% reduces) means no problem. Don't do that every day that's all.

But it's from a prepper site that doesn't cite their own sources.

I found this: https://www.energy.gov/ehss/articles/doe-ionizing-radiation-...

Which uses rem instead of cpm. An on-line converter of unknown quality says 300 cpm is 500 rem, and the pdf from the .gov site says 500 rem is "death probable in 2-3 weeks", but I think that chart is saying that's whole body & no therapy. Where this is probably mostly hair that can be just cut off totally let alone washed, and so the elevated exposure is probably both low and short duration, and medical therapy (whatever that means, if any in this case) on top.

I can't tell, could be the same as just visting a country with a slightly higher background that isn't a problem for anyone, to dead in a month. Leaning towards no problem just because of the short time and apparently mostly external and removable source.

However, it's not nothing either. It's maybe no problem for this person only because they avoided ingesting the water and the water was very quickly washed off and presumably their hair was cut off and all clothes etc removed as fast as possible. It's clearly at least "rather hot" and you can't just play in it and have prolonged exposure and ingestion. It doesn't seem to be "basically zero".

[rippeltippel]

What does it mean for airline pilots? From what I read, they are exposed to more than 400 CPM thought the year.

[scns]

Stewardesses become infertile earlier than women working on the ground.

[roenxi]

The report doesn't read like something involving 500 rem and potential death in 3 weeks. It says "Non Emergency". Can you link to this converter? It seems to be a rather key step that got handwaved. Wiki says [0] there isn't a standard on what a "count" counts.

[0] https://en.wikipedia.org/wiki/Counts_per_minute

[aw1621107]

This website [0] gives the same numbers (300 CPM -> 500 REM). Seems like a candidate for what was used at the very least, and nothing else obviously appeared to claim a similar CPM -> REM conversion capability.

Assuming this website was used, it looks like it does a naive multiplication by 5/3, which seems... simplistic? The rest of the page doesn't exactly fill me with confidence either. No indication of how the conversion factor was derived and there's a bunch of links to other CPM -> <radiation-related unit> calculators. On top of that, the landing page for the root domain boasts about AI capabilities and their AI page prominently features "Elevate Your Content Creation" and "Generate high-quality AI content with ease!"

[0]: https://www.inayam.co/unit-converter/radioactivity/counts_pe...

[roenxi]

I'd love to know how they got to 5/3. It also offers CPM to half-life conversion which has to be at least poorly labelled. That would imply that if two piles of different radioactive substances emit the same amount of radiation (obviously different masses in each pile) they have the same half life. That isn't the case, half life depends on what the substance is which is radiating, not the measured amount of radiation emitted.

[aw1621107]

Given their CPM to half-life conversion amounts to dividing by 60 (not to mention the nonsensical units), I'm not sure I'd place much faith in the website at all.

[qjh]

Obligatory not a nuclear safety or health physics person, but I am a particle physicist and I deal with radiation. CPM is a rather annoying unit because it doesn't convert to dose very well. If you have external 300 cpm (eg. hair), but all of that is in the form of alpha radiation, your actual dose is essentially zero.

It's worth noting that humans are typically radioactive to the level of 3 kBq, or 3000 disintegrations per second, so if I ever realised I had 300 cpm of radiation on my skin as measured by a device that is sensitive to alpha, beta, and gamma, I probably would just shrug and wash it off. Where it might be a problem is if I am dealing with only alpha and beta isotopes, and I'm getting 300 cpm on a gamma-sensitive detector, meaning that the _secondary radiation alone_ is 300 cpm.

(Realistically, I and the radiation safety officer overseeing whatever I was doing would be in serious trouble and have a ton of paperwork, but I just mean it in the abstract)

I mean, 10 grams of potassium has ~300 Bq (that is 300 disintegrations per second) of radiation, so I think I should be able to get my hair far more radioactive than 300 cpm on a beta-sensitive geiger counter if I just slather myself in low-sodium salt from the grocery salt. The salt might be bad for my scalp, I don't know, but the radiation is fine. My point here, though, is that I don't know what equipment the 300 cpm is measured with, what the thresholds are and what the window material is, and that can change things greatly, but my non-professional opinion as the wrong kind of doctor is that it's...probably not a big deal.

We've actually used KCl as a low-level radiation source before, and we joked that when the experiment is done we can just take it home and use it to season dinner.

[Brian_K_White]

Much more useful comment. Thanks buddy.

[roenxi]

The pool. But it isn't necessarily a problem - your hair, right now, is radioactive. Presumably wouldn't trip a measuring device because it'd be background levels.

The linked report doesn't say how radioactive his hair is or give any indication of whether the person in question is threatened by this reading. Could be bad, could be nothing, we just know it is higher than normal.

[ComplexSystems]

It says "The individual was decontaminated by radiation protection personnel but had 300 counts per minute detected in their hair."

[madaxe_again]

For reference, this is about the same in your hair that you’d get from a few hours in a pub in the 90s, never mind working in one - surprising amount of radiation in cigarette smoke from polonium and lead-210.

[roenxi]

It does say that. Can you translate that into a measurement of radioactivity & medical risk? I don't think it is obvious.

EDIT The report below it seems to literally be "nothing interesting happened". The thresholds here for something to be reportable are very low. Frankly I don't know why this story is upvoted so much but I'm not about to make a bigger deal about it than one sentence.

[sithadmin]

300cpm is lower than what you’d be exposed to on a commercial airline flight (400-900ish cpm).

[doetoe]

But is that the same thing? 300cpm says something about the risk to someone near the worker, not about what the worker has been exposed to

[gblargg]

CPM is a function of the detector sensitivity/size and radiation level.

[jojobas]

Water itself is activated by neutrons, even if slightly.

[mlindner]

How? Neutrons slamming into water would break it apart, turn it into hydrogen and oxygen, and possibly activate the hydrogen into deuterium or tritium. But once it's hydrogen (or an isotope of it) it'll turn gaseous and be filtered off.

[jojobas]

In order to become gaseous they need to combine with another atom of the same kind torn free, which is about as likely as combining with a free atom of another kind, form an HO radical and stay liquid.

Tritiated water is a reality of reactor pools.

[golem14]

Obligatory what-if:

https://what-if.xkcd.com/29/

[nashashmi]

Is it not Heavy Water?

[mafuy]

No, just pure water. It's used to isolate against radiation leaks.

[loeg]

Mostly no.