Palisades MI reactor. Currently shut down and de-fueled but a restart of this reactor is apparently underway, with new fuel assemblies being delivered.[1]
> dunno if the life vest bit comment of yours was sarcastic, but it is a funny remark for sure :-)
It was a quote of the linked article:
"Holtec International, which owns the closed nuclear facility, reported the worker was a contractor who was wearing all required personal protective equipment, including a life vest while working near the pool without a barrier in place."
Rather more like "Guy fell over looking into the volcano but fortunately there's a metal fence". The most immediate danger to you is that you'll drown because radioactive water is water and you can't breathe. So the life vest avoids this. In contrast volcanic lava absolutely can kill you before you drown, no problem.
Yes, radioactivity isn't good. You should not, for example, drink this water, or swim in it once a week for good luck. But, it isn't magic death fluid, the worker will have been decontaminated - destroying clothing, washing skin and so on, and the additional exposure means they might get more monitoring, but they're probably fine.
If you work near water you should be wearing a life vest. Especially if it's an area that may be hard to get to or where other dangers are around or if you're alone.
Your radiation exposure next to a coal power plant (thorium in ash) is significantly higher than a nuclear power plant (background radiation). I imagine this is much the same.
This is bad but cavity water radiation is usually very weak. Ingestion could be bad but its not like he swallowed a uranium isotope which would be catastrophic.
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.
Not necessarily nuclear (since chemical and industrial accidents are much, muhc more likely), but highly recommended if you're interested in such incidents and their causes.
“worker fell off roof installing solar panels” — just getting ahead of the ‘anti-nuclear’ folks on here. Energy installations all come with risks, albeit nuclear long tail accidents are mutli-generational and externalised to people not involved in managing the risk
I’ve heard of people falling into the spent fuel pool but never the reactor pool. Usually there are strict FME barriers in place and one cannot even look over into the pool without violating the FME. I wonder what led to the event? Definitely an OSHA recordable!
This is not true at all. I have personally looked into a reactor pool. I remember thinking how easy it would be to literally just jump in. I mean, I'd trip about a thousand alarms and probably end up in prison, but....
was this place one of those who suffered firings as a result of the government shutdown? I believe at least 1,000 employs at nuclear facilities have been fired.
> According to federal reports, the contractor ingested some of the reactor water before being yanked out, scrubbed down, and checked for radiation. They walked away with only minor injuries and about 300 counts per minute of radiation detected in their hair.
> That sounds like a lot, but apparently it isn't terribly serious. He underwent a decontamination scrubdown and was back on the job by Wednesday.
300CPM above background is considered very low - likely why they classified this as non-emergency - the only reason it was reported was per NRC cfr that states any time there is transportation of a radioactively contained person offsite, it must be notified.
For reference, in Canada, that is considered trace contamination and not dose. You would experience 300-800 CPM on a commercial airliner during the entirety of your flight, for comparison.
edit: adding to this that the site in question, Palisades, is shut-down and is under decommissioning and was not operating at the time - so while the water would have had some radioactivity due to exposure to the formerly active core, it was not like falling into an operating reactor or into moderating heavy water... also something that cannot happen with a pressurized reactor such as this one.
> The non-emergency classification is bureaucratic nonsense
FTA: “This is an eight-hour notification, non-emergency, for the transportation of a contaminated person offsite“
I read that as that the “non-emergency” classification isn’t for the victim or the “fell into a nuclear reactor pool”, but for the effects on those outside the facility of sending the victim off site.
A CPM value means nothing without additional context. Counts vary based on detector type and size, radiation type, energy, distance and geometry, all sorts of things. They're not comparable except in identical contexts.
This is why the Sievert exists as a unit.
As a general rule, falling into a reactor pool is probably fine, as long as you don't reach the bottom. (But please don't try it.)
> On August 31st, 2010, a diver was servicing the spent fuel pool at the Leibstadt nuclear reactor in Switzerland. He spotted an unidentified length of tubing on the bottom of the pool and radioed his supervisor to ask what to do. He was told to put it in his tool basket, which he did. Due to bubble noise in the pool, he didn’t hear his radiation alarm.
When the tool basket was lifted from the water, the room’s radiation alarms went off. The basket was dropped back in the water and the diver left the pool. The diver’s dosimeter badges showed that he’d received a higher-than-normal whole-body dose, and the dose in his right hand was extremely high.
The object turned out to be protective tubing from a radiation monitor in the reactor core, made highly radioactive by neutron flux. It had been accidentally sheared off while a capsule was being closed in 2006. It sank to a remote corner of the pool floor, where it sat unnoticed for four years.
The tubing was so radioactive that if he’d tucked it into a tool belt or shoulder bag, where it sat close to his body, he could’ve been killed. As it was, the water protected him, and only his hand—a body part more resistant to radiation than the delicate internal organs—received a heavy dose
> A CPM value means nothing without additional context
Here to confirm this. If you're googling "CPM" you'll find charts that say different things. That's why you need to read carefully. Better, just chill, it is okay that you don't know. It's nuclear physics. It's not a subject you're expected to know about.
For CPM, what matters is "CPM of <WHAT>"
CPM just tells you the number of particle detection. It does not tell you the particle type (e.g. alpha, beta, gamma) nor the energy level (i.e. eV). Without context, it is meaningless.
As an example, I can confidently say you are getting over 100bn CPM right now. The reason it doesn't matter is that this is neutrinos and they're not interacting with you[0]. 1CPM or 1e20CPM, who cares. Conversely, 1 CPM can be deadly. You definitely don't want to be hit by a single ReV (10^27) proton (good luck producing that though). Context matters.
> This is why the Sievert exists as a unit.
Which still needs context.
Sievert is joule per kilogram. So energy divided per mass, much like pressure is force over area. But determining biological impact still takes interpretation. You have weight factors by particle types (e.g. alpha = 2x beta) and there is also weighting factor for internal/external dose and locations like soft tissue (e.g. higher weighting for dose at throat vs dose at hands).
This is why it is incredibly important to use caution when interpreting radiation values. If you don't have training in this it is incredibly easy to unknowingly make major errors. The little details can dramatically change the outcome. Context is critical.
I'm not here to tell you how to actually do the calculation (you'll need a lot more info), I'm here to tell you that it's not easy and you're likely doing it wrong. The experts are not dumb. You're just missing context and a first order approximation is nowhere near enough for an accurate conclusion. It's nuclear physics lol
It shouldn't need be said, but nuclear physics is, in fact, complicated.
Thank you for the followup (familiar with the XKCD)
Dumb question from a true non-expert:
So CPM varies with all those factors you mention, but wouldn't the site HP team know exactly what detector they used, the geometry, distance, etc.? They could convert to dose if they wanted, right?
Why report the ambiguous "300 CPM" instead of an actual dose estimate in mSv/μSv? Seems like that would be more useful for any medical team, any set of potential regulators or regulatory bodies as well as just general public understanding (drawing on my father's work here as he always emphasized the tension between "public fears radiation unnecessarily" and "industry safety protocols are inconsistent")
Follow-up: Is there any legitimate reason to report CPM instead of dose after a contamination event? Or does staying with CPM keep things conveniently vague?
Because from my limited understanding, if they did a proper survey, they have everything needed to calculate dose.
CPM is a measure of rate, GBq is a total amount. And 300 CPM is basically nothing. People live their entire lives in places where the natural background radiation is higher than that with no increased chance of cancer.
300 CPM on its own is both meaningless and not high.
CPM is a raw stat from the sensor. There’s many different designs of dosimeters and they all read differently so you have to ask “what brand and model did you use?” You then apply a function to the data to normalize it into a real unit.
But CPM is the cool thing that makes the click-click-click sound. (The absolute rate of clicks also is not useful.)
Unless I'm misinterpreting what you mean, I believe if it was reflected in the hair in the immediate aftermath, it wouldn't reflect internal circulation because hair does not grow that fast. It would have been from exposure to the pool rather than any amount ingested.
External contamination is not comparable to internal, at all. Bq is a terrible unit to understand radioactive danger. Doses are usually detected in Grey, then converted into Sievert because Grey didn't take into account the difference between Alpha radiation and the others. And even then, when someone is truly contaminated, we calculate effective dose per organ.
The poor guy who fell in the pool probably didn't take any Alpha ray, wasn't taking all the radiation on a specific place, and while in my country we would calculate the dose he took before sending him back to work, he would probably work again in the same nuclear sector (this isn't the case for anyone, I know someone who dive to get the radioactive/explosive/poisonous trash we put in the water in the 50s until the 90s, he now cannot work on any radioactive trash.)
Aussie surfer here, the stings typically are uncomfortable. Some of the deadlier ones can be close to painless and only result in itching and result in you dying from respiratory failure 24 hours later. Others are downright painful with even strong opiate based pain killers struggling to cut through the pain.
Also it's in a way normalised to happen in a few places with beaches. There are vinegar stations every 100m or so. Basically a "yes, it will happen to a few of you".
Is the deadly itchy one of those tiny box jellyfish? More than sharks or crocs, this is why I was an absolute coward and decided not to get in the water in Queensland. There are lots of ways to die, but I'd prefer not to blame myself in my last moments.
There's no significant immediate threat to life or well-being. It's simply not an emergency. We're all constantly exposed to some ionizing radiation. It's a question of how much.
In this case, not much. It's still an exposure event and absolutely worth giving medical attention to assess continued exposure levels from ingested contamination and generally be overly cautious. But that doesn't mean it's ultimately going to be a significant factor in this workers risk for radiation induced disease. It's certainly better than living in the vicinity of coal mining and processing plants.
It isn't an emergency. It was an accident that required medical attention.
If you fell in a lake and accidentally ingested some wayer known to contain some pathagen dangerous to humans, you might seek medical care, but I don't think most people would consider that an emergency. This is similar.
Spiders bite with their fangs, much like vampires bite with their fangs, they don't sting. I might call the tarantula "hair" that makes you itch a sting, but I would feel a bit silly calling it that.
Basically often it could be better to have an incident in a nuclear plant than in some building construction site... But the attention delta is incredibly high. 300 CPM sounds low, I hope they will be fine.
Readit News
Worker was wearing a life vest.[2]
[1] https://en.wikipedia.org/wiki/Palisades_Nuclear_Generating_S...
[2] https://www.mlive.com/news/2025/10/michigan-nuclear-plant-wo...
it sounds like "guy felt down in a volcano, but fortunately, he had a life vest"
It was a quote of the linked article:
"Holtec International, which owns the closed nuclear facility, reported the worker was a contractor who was wearing all required personal protective equipment, including a life vest while working near the pool without a barrier in place."
He was not working in a volcano.
Yes, radioactivity isn't good. You should not, for example, drink this water, or swim in it once a week for good luck. But, it isn't magic death fluid, the worker will have been decontaminated - destroying clothing, washing skin and so on, and the additional exposure means they might get more monitoring, but they're probably fine.
the deeper you get, the worse for you. I assume the first second was critical.
Deleted Comment
Dead Comment
Even drinking it I would think would be completely fine. The water itself doesn't get activated.
https://what-if.xkcd.com/29/
Deleted Comment
https://www.youtube.com/@USCSB/videos
Not necessarily nuclear (since chemical and industrial accidents are much, muhc more likely), but highly recommended if you're interested in such incidents and their causes.
But just now I read that a (sharply reduced) budget had passed the house? [2] does anyone know what the current state is?
[0]: https://www.csb.gov/assets/1/6/csb_cj_2026.pdf
[1]: https://www.pbs.org/newshour/show/only-federal-agency-that-i...
[2]: https://www.safetyandhealthmagazine.com/articles/27090-house...
The non-emergency classification is bureaucratic nonsense. This is an internal contamination event with unknown but potentially severe consequences.
> According to federal reports, the contractor ingested some of the reactor water before being yanked out, scrubbed down, and checked for radiation. They walked away with only minor injuries and about 300 counts per minute of radiation detected in their hair.
> That sounds like a lot, but apparently it isn't terribly serious. He underwent a decontamination scrubdown and was back on the job by Wednesday.
Deleted Comment
For reference, in Canada, that is considered trace contamination and not dose. You would experience 300-800 CPM on a commercial airliner during the entirety of your flight, for comparison.
edit: adding to this that the site in question, Palisades, is shut-down and is under decommissioning and was not operating at the time - so while the water would have had some radioactivity due to exposure to the formerly active core, it was not like falling into an operating reactor or into moderating heavy water... also something that cannot happen with a pressurized reactor such as this one.
https://en.wikipedia.org/wiki/Ronald_Coll%C3%A9?wprov=sfti1
FTA: “This is an eight-hour notification, non-emergency, for the transportation of a contaminated person offsite“
I read that as that the “non-emergency” classification isn’t for the victim or the “fell into a nuclear reactor pool”, but for the effects on those outside the facility of sending the victim off site.
This is why the Sievert exists as a unit.
As a general rule, falling into a reactor pool is probably fine, as long as you don't reach the bottom. (But please don't try it.)
There's even an XKCD "What if" about it. https://what-if.xkcd.com/29/
> On August 31st, 2010, a diver was servicing the spent fuel pool at the Leibstadt nuclear reactor in Switzerland. He spotted an unidentified length of tubing on the bottom of the pool and radioed his supervisor to ask what to do. He was told to put it in his tool basket, which he did. Due to bubble noise in the pool, he didn’t hear his radiation alarm.
When the tool basket was lifted from the water, the room’s radiation alarms went off. The basket was dropped back in the water and the diver left the pool. The diver’s dosimeter badges showed that he’d received a higher-than-normal whole-body dose, and the dose in his right hand was extremely high.
The object turned out to be protective tubing from a radiation monitor in the reactor core, made highly radioactive by neutron flux. It had been accidentally sheared off while a capsule was being closed in 2006. It sank to a remote corner of the pool floor, where it sat unnoticed for four years.
The tubing was so radioactive that if he’d tucked it into a tool belt or shoulder bag, where it sat close to his body, he could’ve been killed. As it was, the water protected him, and only his hand—a body part more resistant to radiation than the delicate internal organs—received a heavy dose
I love this book. Randall is such a gifted artist
For CPM, what matters is "CPM of <WHAT>"
CPM just tells you the number of particle detection. It does not tell you the particle type (e.g. alpha, beta, gamma) nor the energy level (i.e. eV). Without context, it is meaningless.
As an example, I can confidently say you are getting over 100bn CPM right now. The reason it doesn't matter is that this is neutrinos and they're not interacting with you[0]. 1CPM or 1e20CPM, who cares. Conversely, 1 CPM can be deadly. You definitely don't want to be hit by a single ReV (10^27) proton (good luck producing that though). Context matters.
Which still needs context.Sievert is joule per kilogram. So energy divided per mass, much like pressure is force over area. But determining biological impact still takes interpretation. You have weight factors by particle types (e.g. alpha = 2x beta) and there is also weighting factor for internal/external dose and locations like soft tissue (e.g. higher weighting for dose at throat vs dose at hands).
This is why it is incredibly important to use caution when interpreting radiation values. If you don't have training in this it is incredibly easy to unknowingly make major errors. The little details can dramatically change the outcome. Context is critical.
I'm not here to tell you how to actually do the calculation (you'll need a lot more info), I'm here to tell you that it's not easy and you're likely doing it wrong. The experts are not dumb. You're just missing context and a first order approximation is nowhere near enough for an accurate conclusion. It's nuclear physics lol
It shouldn't need be said, but nuclear physics is, in fact, complicated.
[0] https://neutrinos.fnal.gov/faqs/
Dumb question from a true non-expert:
So CPM varies with all those factors you mention, but wouldn't the site HP team know exactly what detector they used, the geometry, distance, etc.? They could convert to dose if they wanted, right?
Why report the ambiguous "300 CPM" instead of an actual dose estimate in mSv/μSv? Seems like that would be more useful for any medical team, any set of potential regulators or regulatory bodies as well as just general public understanding (drawing on my father's work here as he always emphasized the tension between "public fears radiation unnecessarily" and "industry safety protocols are inconsistent")
Follow-up: Is there any legitimate reason to report CPM instead of dose after a contamination event? Or does staying with CPM keep things conveniently vague? Because from my limited understanding, if they did a proper survey, they have everything needed to calculate dose.
CPM is a raw stat from the sensor. There’s many different designs of dosimeters and they all read differently so you have to ask “what brand and model did you use?” You then apply a function to the data to normalize it into a real unit.
But CPM is the cool thing that makes the click-click-click sound. (The absolute rate of clicks also is not useful.)
This might be 500+ MBq (0.5 GBq). Yeah it's a different isotope, but clearly not a "non-emergency"
EDIT: (after 1 hr) - Litvinenko dose was 4GBq - I was wrong by 3 orders of magnitude. My bad
The poor guy who fell in the pool probably didn't take any Alpha ray, wasn't taking all the radiation on a specific place, and while in my country we would calculate the dose he took before sending him back to work, he would probably work again in the same nuclear sector (this isn't the case for anyone, I know someone who dive to get the radioactive/explosive/poisonous trash we put in the water in the 50s until the 90s, he now cannot work on any radioactive trash.)
I guess in a nuclear reactor there is a lingual shift and the word emergency cant be used for just any old 911 call.
Like how Australians apparently call a jellyfish bite "uncomfortable"
https://www.reddit.com/media?url=https%3A%2F%2Fexternal-prev...
In this case, not much. It's still an exposure event and absolutely worth giving medical attention to assess continued exposure levels from ingested contamination and generally be overly cautious. But that doesn't mean it's ultimately going to be a significant factor in this workers risk for radiation induced disease. It's certainly better than living in the vicinity of coal mining and processing plants.
If you fell in a lake and accidentally ingested some wayer known to contain some pathagen dangerous to humans, you might seek medical care, but I don't think most people would consider that an emergency. This is similar.
Not sure about spiders. Are their fangs considered to be teeth? Platypus have venomous spurs, not sure what that’s called.