If I ingest a grain of sand size piece of the Chernobyl Reactor No.4 core | Hacker News Reader

If I ingest a grain of sand size piece of the Chernobyl Reactor No.4 core

quora.com

209 pointstomerds77 comments

I'm baffled at the fact that the answer is entirely about radioactivity. Rather than that, uranium in itself is highly toxic (I mean, chemically).

This is purely hypothetical, as like he noticed, the fuel particle is not soluble in gastric acid. The damage would be much less than that.

Inhaling the similar amount of finely powdered radioactive dust is another story, though.

What movie was that?

Season 2 of 24 I think.

>Me, riding the whole body counter in SP1430, Chernobyl Nuclear Power Plant, after being inside the Unit 4 “Sarcophagus”

What do people do who actually go inside the Sarcophagus these days? I assume there’s monitoring that needs to be done, but I also assume that you can monitor a lot of this remotely. Also, how much longer until Chernobyl is considered “safe”?

I think I heard 20,000 years before it's safe.

The Chernobyl New Safe Confinement has two cranes inside, and a lot of sensors. Incidentally, it's a great engineering project. The only downside is that if you visit now, you can't see the sarcophagus.

Couple naive questions:

1. How does a piece of spent fuel end up in a "grassy bit of ground" outside the reactor? Thought it would have all melted in one big clump in the same spot?

2. Why is Chernobyl still so dangerous if literally ingesting the spent fuel isn't super bad? Or is Chernobyl no longer dangerous?

There was an explosion.

I assume the answer to #2 is that there is quite a lot of waste around. Gamma and beta sources are dangerous just being near you — you don’t need to eat them to have a problem.

> How does a piece of spent fuel end up in a "grassy bit of ground" outside the reactor?

There was a pretty huge steam-based explosion, blowing the top off the reactor building and scattering fuel and various debris quite far & wide.

There is a possibility that the first explosion (there were several) was nuclear-based and not steam-based [1] and produced radioactive plasma, but the plasma jets cut through both the bottom and top of the reactor.

[1] https://www.tandfonline.com/doi/full/10.1080/00295450.2017.1...

1. There was an explosion (edit: two explosions) that began the incident which destroyed the reactor and ejected matter a significant distance.

2. Chernobyl, IIRC, isn't really so dangerous to visit but you should avoid eating or drinking anything in the exclusion zone. Cesium-137 and Strontium-90 will poison you from the inside out. The latter ends up bio-accumulating in bone.

IIRC the uptake rate of Cs-137 is about 10%. Meaning you only store about 10% of what you ingest. Also, we are SUPER safe when it comes to radiation. No chances. No ifs ands or buts. When it comes to dosage, rad workers already have several safety factors from what we can detect an increase risk of cancer, as it should be.

The sensitivity of our tools for detecting radiation never ceases to amaze me. In some ways it's a problem because most people don't understand just how good we are at detecting radiation. Like, not only can we find it in old bits of wood, we can find it so well that we can tell you whether that old bit of wood stopped gathering radioactive carbon from the atmosphere in 10,000 BCE or 10,300 BCE. We can measure how much radiation you get from the sun precisely enough to tell whether you're living on the first story or the second story of your apartment building. But we still get people freaking out about any headline with the word radiation in it. It's crazy.

I think part of it is that a lot of people just don't know the history or the uses of radiation.

For example the history we wanted to find when other nations were testing weapons. We didn't have satellites (or many) so we had to detect from beyond borders. But radiation doesn't travel very far. Solution? REALLY REALLY sensitive detectors.

Most people also don't know uses for radiation outside cancer therapy. I'd bet you most people don't understand that a PET, CAT, or CT scan is radiation. Let alone that we irradiate food to make it safer. I doubt people know how regulated anything dealing with radiation is, or how many factors of safety are added.

Wouldn’t that also apply to all the wildlife in the area? Are there no animals inside the exclusion zone? I get that cancer rates and birth defects would go up, but that’s a bit different from being poisoned, the implication a lack of survivability.

The exclusion zone is actually resembles a wildlife refuge these days. From reports of the numbers of animals present it seems like human populations are much worse for wildlife than low levels of ionizing radiation and other contaminants from the disaster.

The animals’ populations have rebounded, especially those, like wolves and foxes, who’s habitats are least compatible with humans. Still, mean lifetimes, fertility rates and mean body mass are down, while illness are up. This also applies to some plant species. In no way was Chernobyl a strictly good event for wildlife, just that removing humans took away a very strongly negative factor.

The radionuclides I described won't kill you quickly, but over a period of decades, and, well, it's more of a stochastic death as opposed to a definite one.

It may be that shorter lifespan wildlife just aren't as significantly affected, but I've no idea to be honest.

1. There were two explosions - the second of which destroyed the reactor core and distributed parts of the reactor structure (including fuel) over the area.

2. That speck of spent fuel is still radioactive enough after 30 years to push most nuclear industry workers over their annual permissable dosage. Chernobyl itself is still phenomenally radioactive - but is far less so than it was immediately after the accident.

Given that half time is 50000 years for some of its content its is not a big surprise.

The dangerous part, and the part that is discussed in the article, is CS-137, which has a half-life of about 30 years. The longer the half-life of something the less radioactive it is.

>>> That speck of spent fuel is still radioactive enough after 30 years to push most nuclear industry workers over their annual permissable dosage. Chernobyl itself is still phenomenally radioactive - but is far less so than it was immediately after the accident.

I was refelcting on this, not the original article and not on CS-137.

It's not that dangerous. There are people living nearby, it just increases the risk of cancer and other random mutations.

For #1, about 5% of the reactor core was spread outside the building through a series of explosions. (which is a large part of why reactors in the western world all have containment structures) So while most of the core is in a couple of mounds within the reactor building, quite a bit got spread around.

Regarding #2, this is a very small fragment, and there are a lot of them around. Eating this wouldn't do much to you, but 10x a day for a year? Hello cancer.

Who would be eating that much of it 10 times a day for a year?

If you were living in that area and eating local food, such levels wouldn't be impossible to hit - especially if you account for the fact that 'grain of sand sized solid chunk' is pretty close to minimally bioavailable, and so you could hit equivalent dosages with significantly less material.

If a biological process concentrates a radioisotope in something humans consume (let's say a deer), and you eat that deer, you might get a much higher committed dose and a resultant materially higher probability of developing cancer.

Good to know. I was worried for this girl :) : https://www.youtube.com/watch?v=ejZyDvtX85Y

I had a feeling it was a bionerd23 video before I clicked that link... she has some pretty scary radioactivity videos.

I recently watched her videos for the first time (the one where she visited the reactor 4 control room and a few others). A very interesting channel indeed.

It is worth noting that there is almost literally no mention of potential health impacts; almost all the outcomes listed in the answer are regulatory.

On the one hand, that might be good regulation - we don't want workers getting harmed. On the other hand, it serves as ongoing evidence that getting worried because a situation exceeds regulatory standards is foolish.

Given how little attention he gives it the "marginally higher theoretical likelihood of later detriment such as cancer" turns out to be something trivial like less damage than done by drinking sugar water or not exercising.

Heath impacts are literally the first thing mentioned. “probably nothing; certainly nothing obvious and immediate“

A grain of sand is extremely tiny and solid so it’s also got a very low surface area. Further, if it was suck in your lung you would get significant radiation to the same tissue, but in your digestive system food would act as a barrier while also pushing things along.

From a regulatory framework it’s enough to detect and be concerned about which is interesting.

https://xkcd.com/radiation/

This masterfully illustrates the relative risks of various sources of radiation, something that the typical person on the street knows almost nothing about but thinks they do

I live in Japan and read up on this topic after the Fukushima disaster

Which one is 3.6 roentgen, which is not great, not terrible?

3.6R is about 37mSv. So the bottom left one, "ten minutes next to the Chernobyl reactor core at the time of the meltdown", also the top right "maximum yearly dose permitted for a radiation worker" is 50mSv too - I guess the show did its research.

The "ten minutes next to Chernobyl reactor core at the time of meltdown" is 50 Sv, not 50mSv.

3.6R was measured by the small dosimeters on site (and also happens to be their maximum read value). The bigger dosimeters didn't work or also maxed out and the person in charge didn't believe it.

The show mentions a 1500R value later on but outside the reactor building.

I had a really hard time with the title displayed here, which is a truncated version of an already-confusing title on Quora. The actual title, with, I think, desireable punctuation included, is "If I ingest[ed] a grain-of-sand-size piece of the Chernobyl Reactor No. 4 core, what would happen to my body?"

There are things much scarier and devastating than uranium. It took 10 micro-grams(10^-5 g) of Pu-210 to poison(ARS) Litvinenko. You cannot see that amount - so tiny it is. And the damage is almost 100% gamma rays - so its hard to detect and the damage is lowered when handling and maximal when ingested.

A discussion about the everyday occurrence of radioactive sources may be more productive.

Here or in the Quora post? There's plenty of people here that know quite a bit about reactors and radiation. Ask away.

Both. This question seems like a way to emphasize extreme dangers of radiation.

I left with more questions than answers...

As it is usual when reading Quora "answers".

I've watched this interesting (but long) talk by Brian Sheron, retired director of Nuclear Regulatory Research:

https://www.youtube.com/watch?v=ryI4TTaA7qM

It gives me a better understanding of the risk of nuclear power, particularly for current US reactors, and what our regulatory agencies actually focus on: really it's on preventing direct radiation induced deaths, and not so much on property damage. So: It's not so much that accidents directly kill people, instead they kill the land. The idea is that loss of cooling incidents are contained for a significant amount of time- at least 8 hours. I'm dubious, but this is thought to be enough time to evacuate people from the land that will eventually become contaminated. Only when people move back do people die, and then only from increased cancer risk (Brian says this becomes an EPA problem). So now the land is lost, because who would move back? [of course this focuses only on deaths from radiation, and not for example, deaths caused by stress to elderly people forcibly relocated].

I did not remember when people were evacuated after the Fukushima accident, but it was pretty quick, here is a timeline:

https://www.oecd-nea.org/news/2011/NEWS-04.html

There is another question I'm still trying to answer. If the final heat sink is lost (someone blows up a dam), can the reactor be shut down without incident, assuming no blackout? This would require that the decay heat is spread across a large enough surface area. I'm not sure if the containment building provides such an area (a 1000 MW reactor generates ~70 MW decay heat after shutdown). It reminds me that this is another area that NRC does not focus on: "terrorist attacks are a military problem".

Edit: well I answered my own question from wikipedia entry on containment building: "While the containment plays a critical role in the most severe nuclear reactor accidents, it is only designed to contain or condense steam in the short term (for large break accidents) and long term heat removal still must be provided by other systems." So if the heat sink is a man-made lake held by dam, it's a big risk (of course dam loss would cause direct loss of life anyway). I was wondering about this because my inlaws live near Duke Energy's Oconee Nuclear Station, on man made Lake Keowee https://en.wikipedia.org/wiki/Lake_Keowee

Gotta love the conclusion:

"In summary, it is preferable to not eat spent nuclear fuel."

It was interesting to see that it truly was only "preferable" and not "mandatory" or "this will kill you" IMO

That's the interesting thing: it's not really very hazardous, but it is awfully annoying.

And not even "annoying due to health issues" but instead "annoying because it'll make you leave your job if you work in a field with dosage limits" and "annoying because you'll be setting off the radiation detectors when leaving the exclusion zone"

To be fair, it has had several decades to decay, and the most dangerous radionuclides are the ones with short half-lives and thus high output. It's pretty amazing that it's still that dangerous given it's had over 30 years to decay.

And it’s really tiny. Lots of serious poisons would be harmless at that dose.

Noob question, if it decays so quickly, how come there's so much of it around this late in the Earth's history? Or was it created only decades ago, by artificial means?

Some things decay quickly and some very slowly, forming a sort of chain where the events might happen fast-slow-fast-fast-superfast-superslow-slow-fast-medium-fast-slow, or something like that.

So these fast-decaying things disappear quickly but are also being constantly created by things spontaneously decaying into them. The point of a nuclear reactor is to increase the overall rates of decay, so you end up with disproportionately large amounts of the short-lived isotopes as opposed to what you would find in nature.

https://en.wikipedia.org/wiki/Decay_chain

If you scroll down you see thorium series, neptunium series, uranium series, and so on. You can see the half-life at each step.

The short answer is, we created it. The half-life of Uranium 235 is 700 million years, so there's plenty of it around. When you bring a bunch of U235 together and cause it to undergo fission, it creates a bunch of the shorter-lived stuff as a decay product. Especially when a reactor melts down; you get a lot more of the stuff you didn't want, in a much more uncontrolled manner.

Sort of not really? There's some specifics to this hypothetical situation that minimize it's effects. In this scenario you're consuming a solid piece of radioactive material that passes through your body and is quickly expelled. When you have a Chernobyl type disaster or a nuclear explosion the radioactive material is atomized and spreads through the air. As you breath in the radioactive particles they pass directly into your blood stream.

Now you tell me! What are you going to tell me next, that yellowcake isn't made from flour?

This is how you know it was written by an engineer. The executive summary is at the bottom.

really puts my mind at ease

If we were to make an analogy between radiocative matter entering the body, and toxic information entering the mind, what metrics do we use to measure the dangerous effects of the information? How long it lasts or how deeply it can modify conscious/subconscious brain processes?

There's no such thing as dangerous information, only truth and not truth.

I disagree having read about people who work as content moderators for websites like YouTube. They frequently suffer from acute forms of PTSD having only passively consumed information. If information can cause PTSD, I would consider that information dangerous to one's mental health.

Not to mention simpler examples like the anti vax movement. Which has put not only individuals in danger, but whole populations. There's plenty of examples of information leading to harm.

(This comment is neither a recommendation for censorship nor a push for freedom is speech)

That's true. I also thought of something like state secrets where a government agent might show up one day and make you disappear.

But that type of information is only indirectly dangerous. The actual danger is the government agent or your personal actions based on misinformation in the case of antivaxx.

I was thinking more in terms of information that is objectively dangerous. Just ingesting the information alone is enough to cause damage.

I was also reminded of an article I read recently about artists and animators who worked on the newest Mortal Kombat game suffering from PTSD due to the graphic nature of their art and the reference materials they had to use.

> I was thinking more in terms of information that is objectively dangerous. Just ingesting the information alone is enough to cause damage.

I think there are cases for that too. But it depends on your psychology. For example there are mathematicians who have studied infinities and gone insane. Others haven't. Probably other factors involved, but it helped push them over the edge.

I would propose the unit of "Cuil". 1 Cuil is present when a piece of information causes permanent PTSD in 50% of the people viewing it within 1 week. 0.1 Cuil cause PTSD in 5% of the people viewing it and so forth. Measurements over 2 Cuil express timeframes shorter than 1 Week. So 100 Cuil would cause permanent PTSD symptoms within 8 hours.

Alternatively, you measure how long people remember the video vividly and express the danger as the half life of the information related to it's damage.

Cuil idea!

>There's no such thing as dangerous information

There most certainly is. We actively codify for it in most societies in a myriad of ways. See: Nuclear technology secrets, CDC protocols, and the fact that things like PTSD exist.

And to your underlying point: stop assuming everyone is rational or will act in the best interests of society with information. There is plenty of information available to you to negate that assumption.

Such as people who would gladly steal your identity for financial gain.

That's an over simplification. True information can be dangerous or not. Falsehoods can be harmless or not. Context has a significant impact on how the information is treated and the ramifications that come from it.

Game of Thrones analogy: an important character being told they are the true heir to the throne results in another character burning down a city. Information can be dangerous depending on the context. Also in the show, The heir’s father in the story kept the information secret to protect that persons life.

Tell that to a gay man in Iran who is outed among many other examples.

I feel like many of these are examples of that what people do with the information is dangerous, not that the information _itself_ is dangerous. Perhaps a slight difference, but one that I think exists.

I think people suffering PTSD is a better example of how information can be dangerous.

There's a difference between facts and information.

You may be interested in reading this paper from Nick Bostrom, where he outlines the dangers present in certain types of truthful information: https://nickbostrom.com/information-hazards.pdf

Glad someone else linked this! I tried submitting it to HN but it didn't gain much traction.

> There's no such thing as dangerous information, only truth and not truth

Please submit some proof of this extra-ordinary claim. There is a lot of evidence to the contrary. And we're not even yet talking about whether 'Truth' is a binary value.

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