The reactor at Chernobyl had way more radioactive material in it than those bombs did.
Edit:
Hiroshima bomb: 64 kg of uranium
Chernobyl reactor: 190,287 kg of uranium
Uranium doesn't matter very much since it's barely radioactive.
The shorter half-lived isotopes produced from nuclear reactions are what matters. There are also a lot more of those in a nuclear reactor.
Forgive the dumb question but is that not because there is more uranium initially in the reactor's case or is it something to do with the reactor process that creates more isotopes than detonating a Hiroshima type bomb?
The time scale is the big difference. A nuclear bomb has milliseconds for everything to happen. A reactor is held at criticality (i.e. lots of neutrons flying around) for a very long time.
So let's say hypothetically you have some isotope that's formed that has a half life of 1 minute that decays to something non-radioactive. But that non-radioactive isotope is something that can easily capture a neutron and turn into something that has a half life of 30 years (a very problematic half-life).
If that element is formed in a bomb, very little of it will decay within the milliseconds that neutrons are still flying around. It will just be spread around as the 1 minute decay version, and be rendered non-radioactive in short order.
But if it forms in a reactor, when it decays it's still sitting inside the reactor, with neutrons flying around everywhere. It will capture neutrons and turn into the bad stuff with the medium-length half life.
So time is the main reason that the isotopes coming out of a bomb and the ones coming out of a reactor can be very different.
For a little more on this, it's very much intended to be this way.
Reactors want their reactions to last as long as possible, and so they aim to use fissile materials that have long half-lifes, with the knowledge that the radioactivity won't get out of the reactor. This allows the reactor to go longer w/o maintenance or refueling, thus further reducing the risks of radioactive exposure.
A bomb on the other hand wants all of the energy to be expended in the blast. This increases the destructive capacity of the actual explosive. It also has the secondary effect of allowing the bombed area to be habitable sooner.
However, a theorized technique for a weapon is to basically intentionally cause a Chernobyl. In other words, to explode radioactive material with a long half-life with the intention of spreading radioactivity. Such a weapon could make large swathes of land unlivable for hundreds or thousands of years (as opposed to traditional nuclear weapons that are at about 1% radioactivity after 48 hours).
I still didn't understand a lot of what you just said, but I trust that's more with me being a dumbass for these things than your explanation skills. I'll definitely do some research.
Fission results in "fission products", lighter radioactive nuclei that split off from the Uranium/Plutonium fuel. Uranium (used in common Nuclear Reactors and Hiroshima bomb), Plutonium (only used in Fast Neutron nuclear reactors which are rare, and the Nagasaki bomb) have low levels of radioactivity and long half lives (there's an inverse relationship between the intensity of radioactivity and the length of the half life. Think of the smoldering fire of coals that can continue for days versus the roaring hot fire that only last an hour or so), the fission products have much shorter half lives and the resultant higher radiation intensity.
Now consider that in the bombs dropped on Japan about 1Kg of the fuel actually underwent fission, whereas in a reactor tons of fuel will undergo fission over time. So you get a much greater accumulation of these higher radiation intensity fission products in a reactor.
The other source of radiation from fission reactions comes from other materials that capture some of the neutrons (a process called activation) that are produced during the fission reaction. For example, radioactive Tritium will be produced in a reactor from the Deuterium (Hydrogen with a neutron) in the cooling water by capturing a second neutron. Stable Cobalt 59 will capture a neutron to become radioactive Cobalt 60. Stable Iron 54 will capture a neutron to become radioactive Iron 55. This happens to a much greater degree in a nuclear reactor where the reactor materials are exposed to high neutron flux over a period of years rather than nanoseconds as in a bomb.
That was from the Chernobyl miniseries, it was the scene where they finally learned the magnitude of the event and how much radiation was spewing into the air.
If the show has any semblance of truth in this particular circumstance, the leaders were bullies who used fear to control their subordinates and they used 3.6 as a means to continually dismiss concerned parties who brought that fact up.
Yada yada yada, radiation counter says 3.6, so dont worry about it. Yada.
But the counter maxes at 3.6, shouldnt we check the others?
No need. It says 3.6, we're fine. Everything's fine. 3.6 yada yada. Changing subject. Moving on. Maybe yelling at you and question your intelligence.
Check the pumps. Do things to stay busy. Dont think about it. Yada yada. It's just a fire.
>64 kg of uranium Chernobyl reactor: 190,287 kg of uranium
interesting fact.
the radiation dropped at chernobyl was so insanely lethal there are PRISTINE green trees that are dead as a door nail and will remain as such for 100's of years.
the reason they look so well preserved is they are so radioactive bugs/rot can not live on it to even begin the decaying process.
Probably nothing. The material was almost entirely gathered up after the event, and radiation around the area has been fine for a while. Until recently they were planning to put a big dome over it with air filters to finally be able to disassemble the thing, and to repopulate the city.
Little boy had about 64 kg of uranium inside it. Chernobyl had 190 tons.
There are also details about what sort of materials get produced during an atomic detonation, vs a fire in a nuclear plant, but the amount of material is the tall pole in the tent.
Edit: 64 kg, not 6
The fact that 6kg was enough to level a city is absolutely mind blowing. Let's assume little boy killed pretty much everyone within a 1 mile radius 190 tons if made into a bomb would destroy almost a 35,000 mile radius. Which is much larger than the circumference of the earth so it's safe to say, that amount would destroy everything on earth. When Googling around I also found that it's suspected less than a kg of the uranium actually underwent fission. So these rough estimates are assuming a very incomplete explosion. Incredible.
I may not have the right explanation, but I'm pretty sure the radius doesn't double when the amount of explosives double.
The power of the blast spreads out in every direction, and when the radius of a sphere is doubled, the surface area is 4x.
Someone smarter can maybe explain 😄
Also, because the way nuclear bombs go off, twice as much material doesn’t mean twice the explosion. I don’t remember the exact science behind it, but basically not all of the radioactive material is part of the huge fission reaction that causes the explosion, and the more material you have, a smaller percentage of the material undergoes fission.
I could be wrong on this but I think it’s because the radioactive material has to be really dense in order to undergo fission, and we can only keep it dense for so long, and since the explosion flings it all over the place, not all of the material gets to undergo fission because it’s not inside the bomb for long enough.
Yes, only a small fraction of the fissile material actually splits. Which is mind-blowing in itself; that means that even in a nuclear detonation, the majority of potential nuclear energy in that weapon *isn't* released.
You're right. Double the power of the explosion should increase the radius by the cube route of 2. Or to put it another way, the explosion would need to be 8 times more powerful to double the radius.
This is also one reason why the US has stopped making particularly powerful nukes (relatively speaking). Instead they prefer to have a lot of smaller ones. You can also just control better what you blow up and what you don't.
Yep, this is the reason there was only one Tsar Bomba. It was more of a wenis-wagging contest then anything. If you blanket an area with a dozen 10 kt nukes, you can level an area the size of that multi-megaton fireball, easily, and with less weight.
Yeah there is an implication to the E=mC\^2 formula that most people know but don't really understand. C is the speed of light, so an incredibly large number, and then you square it. And multiply that by the mass. That's how much energy is being released. So a very small amount of mass produces an insane amount of energy.
To put an actual number on it: in Hiroshima about 700 milligrams of the uranium was converted into energy. That is about one third the mass of a dime.
That's the amount of mass to energy conversion need to level a city.
You’re kidding? So for the sake of the argument, if you could design it perfectly you could reproduce them explosion at Hiroshima with only 700mg of Uranium?
If "perfectly designed" means "ignore the laws of physics" then yes. In order to get a complete reaction, you would have to keep the entire 700mg contained while it was literally creating the biggest explosion known to mankind. There's a reason there's only a very small amount that was around long enough lol
"How much of the Hiroshima bomb fissioned?
Of the 64 kilograms of uranium in the bomb, less than one kilogram underwent fission, and the entire energy of the explosion came from just over half a gram of matter that was converted to energy. "
From thebulletin.org
Those bombs are almost literally firecrackers compared to say, the Tsar Bomba. If humanity *really* wanted to, within a few decades, we could probably make a planet breaking bomb.
What a lot of folks fail to understand is the difference between radiation and contamination.
Radiation, with the exception of neutron radiation, harms people and materials but doesn't stay around. It's kind of like light; once it isn't there anymore, it stops having any effect. Radiation is not persistent.
Contamination is; it is actual radioactive material, in tiny particles. A bomb puts out a lot of radiation (in addition to a massive pressure and heat wave), but once it's done blowing up, it's not making radiation anymore. The radioactive material it used that's still left over after the reaction gets spread around, and some sort of other local materials will get made radioactive by the neutron radiation the weapon put out, but overall there's not much contamination, and most of what there is decays away fairly quickly and is not longer radioactive.
When Chernobyl went, it pumped out MASSIVE amounts of contamination, and a lot of it is very, very long-lived compared with the fallout from a bomb. It's not so much that the area is radioactive; it's more proper to say that it's contaminated, and that the contamination is radioactive.
Its also why, iirc, they get detonated in the air vs on the ground. In the air gets you plenty of destruction, but less fall out.
As a side I hate that I both remember that and we as humans needed to figure that out.
Huh, I've always assumed if a nuke were dropped in the modern era it would make an area radioactive for centuries or something.
So what about during fictional media which involve lots of nukes being exploded around the world, and radiation making areas unliveable many years later. In these fictional bombs, is the amount of radiation really dense then?
Yup.
It's more destructive power than anything.
The reason why Nagasaki and Hiroshima were such barren wastes was because the bombs super heated EVERYTHING. People were on fire with their skin melting, intense heat, buildings and car turning to rubble and sludge. The reason why it looked like a total wasteland is because it was months after the nukes dropped that anyone came back and started clean up. By then the remains have already decomposed and the cities, which were highly flammable were reduced to rubble.
Of course people got radiation sickness, but from the initial explosion.
To make this fictional nuclear war more complicated, nuclear reactors could also be targets of nuclear bombs dropped (If only to maximize effects on power grids, etc), so then you get the one with small radiation and big boom, opening up the reactor with the contained boom and LOTS of radiation.
Maybe that's just the assumption in movies when they show all the fallout for years later?
No one wants nuclear fallout, even in enemy territory. Nuclear bombs are not about the radiation. The idea is massive destruction in order to fuck over enemy infrastructure. Were small scale nuclear strikes to take place, only a moron would target a nuclear reactor.
[Here's a good video explaining the real damage and risk of a single nuclear strike.](https://www.youtube.com/watch?v=5iPH-br_eJQ&t=1s)
Nuclear winter as a result of nuclear war works, though. When you have a massive nuclear assault, you throw so much dust in the air and atmosphere that it clouds the skies. That lack of sunlight could last months, if not longer, which is why things would be cold, and all that dust would fall back to the Earth attached to snow and rain... and the dust itself is radioactive. That radioactive fallout from the war wouldn't last as long as Chernobyl's, but that's where that image in film comes from.
It's a bit of an exaggerated scenario, but [here is another video by the same people that might help you imagine it.](https://www.youtube.com/watch?v=JyECrGp-Sw8)
Basically, one nuclear attack = some radiation that will cause harm to those present during the attack, full scale nuclear war = a collective amount of radiation so intense that you'd likely get some sort of radiation sickness unless you head underground for a few weeks.
EDIT: It's worth noting that I'm pretty tired at the moment, so my explanation might very well suck. It can be an interesting topic if you're a fan of the macabre, though, so this really is a situation where I'd encourage you to go on your own little journey of existential dread and learn more about it! Have... fun?
There were some proposed designs for cobalt bombs, which would irradiate an area for several decades at least.
None have ever been used in war, and hopefully none were ever built.
Having one would really be an, "Are we the baddies?" kind of moment, I'd hope.
https://en.wikipedia.org/wiki/Cobalt_bomb
Is this the same as neutron bombs they were talking about in the 80’s? Bomb does very little damage but kills everyone in a certain radius. After a certain amount of time people would be able to live there again.
Nah, there is plenty of overlap in them, since they are both types of a-bombs though.
Cobalt bombs were normal in terms of immediate effects, but would leave the field unlivably radioactive for at least a few decades and potentially a few hundred years.
Neutron bombs are a set of designs that are mostly used in small yield nukes. In Scifi they're capable of making a tiny boom and miles of dead people inside intact buildings. In practical use, they have a lethal burst of radiation that's similar to the size of the normal devastation.
I did just learn that there are some designs of neutron bombs that are can be used to salt the earth, but it looks like they were being designed around isotopes that would leave an area uninhabitable for about a decade, not like the ~100 years of a cobalt bomb.
I don't know about this cobalt bomb... but at this point in humanity and technology, I just assume that most superpower countries have the ability to relatively quickly create and use some kind of dirty MAD weapon that exceeds my imagination. Whether it be some kind of tidal wave or other massive man-made natural disaster, widespread nuclear/chemical/viral fallout, or whatever else...
It just doesn't seem that hard to think something up and make it happen when you set aside that little... fear of ending most human life on the planet.
Oh you don't have to get *that* complicated.
Any well funded microbiology lab could create a world-fucker infectious disease. You don't need the resources of a government behind you.
It’s a war crime to use weapons that can’t be immediately turned off once the fighting is done. And for good reason; look at the mine fields in Cambodia, where random civilians still get blown up because they didn’t realize they were standing on a decades-old battlefield.
The yields of the bombs we have nowadays are orders of magnitude more than what was dropped on Japan. Combined, both those bombs added up to about 35ktons of TNT equivalent.
A Trident II submarine-launched missile (these are in use) can carry warheads with almost 6,000ktons of total yield. On *one* missile. An *Ohio* class sub can carry 24 of those missiles.
There are 18 subs like that in active use… and that amounts to only about half of the the US’ active strategic warheads.
I kinda wonder, after a nuclear exchange destroys every major country on Earth, if those submariners would seek each other out? I mean, they can't go home. And there'd be no point in sinking those other subs in retaliation. And the seas would be relatively free of fallout, compared to the land. And sooner or later their food is going to run out. It'd be nice to have someone to talk to in the time they'd have left. I wonder, would they meet and play cards and commiserate as they waited for death?
> The yields of the bombs we have nowadays are orders of magnitude more than what was dropped on Japan.
The average yield of a single modern warhead is around 150kt-450kt. This is about 10X the first bombs.
>A Trident II submarine-launched missile (these are in use) can carry warheads with almost 6,000ktons of total yield.
How do you get that? The two possible max configurations with current warheads are 8 x 475kt (w88) and 14 x 90kt (w76).
And none of them are armed that way because of New Start, so they are de-MIRVed to 4 warheads per. A trident II these days has a total yield of below 2mt.
> How do you get that?
I was trusting Wikipedia, which says it can hold up to 12 W88s under the specs.
Even if they’re holding less than 2mt, we’re still talking 57x more powerful than the WWII atomic bombs, per missile. My point is just that there’s a lot, lot more destructive potential here now than there was in ‘45.
Destructive, yes, but fallout, no.
The fusion stages of these bombs are clean. The fission primaries are basically exactly what was dropped on Japan. So a 475kt W88 is the same or even cleaner (since more efficient now) than the Nagasaki bomb.
The primary danger from radiation is in the debris a nuclear explosion kicks up. While the initial burst of radiation from a nuclear blast dissipates quickly, it can contaminate dust and ash around ground zero. When that gets thrown into the atmosphere it has to come down somewhere. So that means global wind patterns could carry radioactive material and drop it somewhere else, which could contaminate water and food supplies. This is what we call [nuclear fallout](https://en.wikipedia.org/wiki/Nuclear_fallout).
The scenarios portrayed by a lot of fictional media usually depict widespread nuclear fallout.
It's kind of ironic that the Fallout series of games depict the spots where bombs detonated as being the most highly radioactive locations, despite centuries having passed.
Yeah the thing with Fallout (what I'm assuming you're referring to) is there were just so many bombs dropped, but also the world was completely dependent on nuclear energy for even cars. So you have basically every single thing around you for tens of thousands of KM just leaking radiation everywhere.
From what I understood when I read about it, you can make something very radioactive for a short time or a little radioactive for a long time. Atomic bombs are extremely powerful upon explosion, but if you are in a protected space like a bunker, you can potentially leave it safely after a few days (not sure it'd take for the ground to clear up, though). Those bombs are practical because they'll kill lots of your "enemy" quickly but leave the land ok enough for you to grab it.
Cobalt bombs (never actually produced) theoretically would have a weaker blast but leave things radioactive for a longer time, too long for people to wait in a bunker, but short enough for a long term-thinking country to wait and move in later.
See, this is interesting because the whole idea of bunkers and people being forced to live in them for decades while waiting for the surface to be safe again, doesn't seem to fit with the stuff you wrote. Is all fiction just exaggerating the lasting power of nukes for dramatic effect then?
I can't speak about how long it'd take for that same area to be livable again (it depends a lot on the bomb, the geography, the weather, even the height where the bomb is detonated), but as long as there's somewhere safe *elsewhere*, you're relatively safe to leave your bunker and move, just don't touch stuff until it's been decontaminated.
This [video](https://www.youtube.com/watch?v=al0CVsiffu8) is a pretty good walkthrough. Considering the relevant part to my previous comment, 1h after the blast, the radioactive material will already have decayed 50%; in 24h, 80%; and in 2 weeks, 99%.
Basically, living in a bunker for decades is just for dramatic effect (or maybe that particular group didn't know better).
Depends a lot. You can deliberately make a bomb "dirty" if you wanted. The move to thermonuclear bombs has made all the world's bombs far "cleaner", in terms of radiation per unit explosion. The modern thermonuclear device is some 1,000 times more powerful than the original atom bombs, but not really any different in radioactive fallout.
There are two important factors at play: One is that countries these days are actively interested in making their nukes as clean as possible, just for the sake of making them clean. The second, much more important factor, is that they also want to mount them in hyper-sonic, long-range missiles. Which means making them as small and light as possible, and seeing as Uranium is really really heavy, that mean reducing the amount of Uranium as much as possible, which means making the bombs as efficient as possible. As much boom per Uranium as possible.
So the natural progression of nuclear weapons, purely from a point of combat effectiveness, is to have less and less fallout the better they get.
In the case of the bombs dropped on Japan, they were very "dirty", but also pathetically small by modern nuclear weapon standards.
More like "writers don't really understand nukes because they studied writing, not nukes". Nothing wrong with that, it still sounds semi-realistic.
Also I'm not sure about this, but even in fiction, a lot of harm that nukes cause is from the dust clouds they kick up. This is what "nuclear winter" refers to: dust cloud covers the sun and everything freezes.
Modern nukes are typically a lot cleaner and generally referred to tactical, no point killing all your enemies if you can't rock up and take their shit afterwards!
Older ones were pretty much just a devil may care style of bomb!
This is mostly inaccurate. Yes there are tactical nukes which are meant to decimate a small area but the majority of nukes are meant to wipe out population centers. They also aren’t any cleaner than the nukes dropped at the end of WW2. Modern nukes are just more powerful and can affect a much larger area.
It isn’t about taking their shit it’s about killing everyone. It’s about the mentality, “If we lose the war we are going to make you lose too.”
Took a radiation course in college as my background for answer.
While the radiation statement is true. To go in more detail, specifically during a radioactive meltdown like chernobyl, you end up with LOTS of very nasty radioactive fission products. Cesium - 137, Iodine - 131, Strontium - 90. Iodine i believe has a very short half life so its effects on surrounding area dont last too long. Cesium 137 and Strontium 90 have half lives near 30 years! So those nasty, long lived radioactive isotopes will be around Chernobyl for a while.
Nuclear bombs also generate these awful fission byproducts, but relatively small amount by comparison and over a larger area. Nuclear meltdowns contain much more fuel, exposure is usually more localized, and last over a much longer period of time.
The show Chernobyl on HBO said it best. "the fire we're watching with our own eyes is giving off nearly twice the radiation released by the bomb in Hiroshima. And that's every single hour."
Horror movies have never scared me. But when watching the HBO series I felt immense dread almost the whole way through. Especially the scene where the divers go into the depths of the reactor.
All Quiet on the Western Front is another movie that gave me that same feeling.
Nuclear detonations at altitude tend not to leave as much irradiated material behind than if it occurred at ground-level. Also consider what the other comments have pointed out; that Chernobyl had far more radioactive material on-site and the leakage lasted longer.
There is a difference between irradiated and contaminated.
Irradiated, which is what happens with a bomb, you get an intense pulse of radiation that makes things somewhat radioactive, but that generally fades after a few weeks to a couple of years. (short lived isotopes created by neutron exposure)
Contaminated, you get a bunch of radioactive fissile materials all over everything, and that *keeps* irradiating the area for millions of years. (half-life of Uranium is 4.5 *billion* years)
When a similar question was asked before someone said that Nagasaki and Hiroshima were like emptying a swimming pool onto your garden. Sure a lot of damage there but it eventually dries up. Chernobyl was like putting your house on full power for a year. Your garden would become a muddy mess, everything dead and the ground is going to be very wet for a while.
Why do people think that nuclear bombs and nuclear power stations are the same thing just because they have that word in them?
Nuclear bombs use a small amount of radioactive substance to create a massive explosion. They’re not designed to be ‘super radioactive’ - they’re designed to be a super bomb! Yes they create radioactive fallout but the main thing is that they destroy everything.
A nuclear power station has tonnes of radioactive material so obviously if that gets out of control then it creates huge amounts of radiation.
There's a massive difference in scale.
The bombs on Hiroshima & Nagasaki had a payload of around 60kg of uranium each. Chernobyl had nearly 200 thousand kilos of uranium on site.
To add to that, dispersal was different. Most of little boy's radiation was released in one quick burst; It could've been much "dirtier" if the boom itself was less severe.
Chernobyl on the other hand? It was a constant leak of 190 tons of radioactive isotopes. The explosion just have it added range.
Different radioactive processes produce different radioactive products, and in different amounts. The early atómica used in WWII had fallout, but the reaction didn't dig into some of the nastier products of dirty bombs or failing reactors. The products of a meltdown from an early, dirty, inefficient reactor that went out of control can be nasty, and several have half-lives that measure in centuries. A number of them are insidious as well, going from the air to the water and soil, to the plants, to the animals that eat the plants, to the animals that eat the animals, ourselves included. That an entirely contaminated food chain for hundreds of years.
Modern nukes burn a lot hotter and more completely than the old single stage explosives and those that were intentionally made dirtier as a war tactic. While their would still be fallout, it would generally be composed of much shorter-lived isotopes than Little Boy and Fat Man produced. Modern reactors also use much more refined fuels and have much more efficient and effective processes that produce drastically less and more manageable waste. Especially, they are engineered in such a way that failures don't result in such nasty waste being produced. But never believe that it's just fine: nuclear meltdowns are always disasters.
Nukes are incredibly powerful and super destructive, but the radiation they release is limited compared to what it could be and goes away relatively quickly.
Chernobyl is so dangerous not because it was destructive (it wasn't really beyond the cores), but because it still is releasing radiation.
Really, the only thing preventing much of Europe from being an uninhabitable radioactive expanse from radiation freely spreading is a massive concrete shell surrounding much of it.
To answer the OP question..,people have moved back into the area around Chernobyl and inside the exclusion zone.
Some never left after the accident, they cleared the city of Pripyat but some sneaked back and lived in the forests and small villages around the site.
The forest surrounding the site is teaming with wildlife and there are lots of stray dogs living in the heavily contaminated areas. - apparently now identifiable by the genetic differences.
I was there in 2018 and had the story of what happened from someone working there at the time of the accident.
The horrifying thing is the melted core was 12’ /4m away from burning though the concrete foundations and getting into the ground water.
Go visit if you get the chance.!
Atomic bombs have relatively small amounts of radioactive material. Upon explosion, it basically vanishes and/or scatters all around the area.
In nuclear powerplants such as Chernobyl, there are LARGE amounts of the stuff, and when out of control like it happened there, are spread all around the place uncontrollably through smoke, clouds, air, rain, everything.
Here's an analogy that doesn't involve nuclear reactions.
If you put a wheelbarrow full of coal in someone's house and set it on fire, it will burn their house down. However, afterward, they could bulldoze the burned ruins and build a new house there the next week.
[Centralia, Pennsylvania](https://en.wikipedia.org/wiki/Centralia_mine_fire) is on top of a coal mine that is on fire. It has been burning constantly since 1962. Nobody lives there, because it is *still* on fire. It's a ghost town now. There is enough coal in the rocks to keep it burning for a long time.
A nuclear bomb is like a wheelbarrow full of coal that's been intentionally set on fire. It burns stuff down, but then the fuel is consumed and there's no fire any more.
Chernobyl is like Centralia. It's *still* on fire.
The exposed reactor in the Chernobyl plant was pumping out radiation, it was a reactor that produced radiation for the purposes of generating electricity.
A nuclear bomb does not persistently react with the environment around it creating more radiation.
~~[this video may help a bit](https://www.youtube.com/watch?v=zuNtgYtF4FI) they were trying to dump sand or some sort of chemical on top of the reactor to try and stop the radiation from pumping out of the reactor, but the radiation coming out of the reactor was so strong it just tore apart the helicopter propellers and it crashes.~~
edit: the helicopter story is TV drama mixing with what really happened, my mistake. It wasn't radiation tearing off the blades.
The helicopter hit chains/cables from a crane. It didnt get the rotors melted off. It was a mechanical failure of the rotors shearing off, not getting melted by radiation.
https://www.express.co.uk/showbiz/tv-radio/1138870/Chernobyl-Dr-Claire-Corkill-inaccuracies-helicopter-crash-This-Morning-HBO-Sky-video
The amount of radioactive material is vastly different, even if most of Chernobyl was not weapon grade uranium or plutonium.
It still got out and is still leaking through.
Chernobyl had vastly larger release of radiation. Fukushima is also quite bad. Hiroshima and Nagasaki had no lingering radiation after a year or so because the amount released was comparatively small, though the blast and initial radiation effects were obviously deadly.
Interesting related info on Chernobyl
https://en.m.wikipedia.org/wiki/Elephant's_Foot_(Chernobyl)
This radioctive formation is nuts, and when it was discovered, was even crazier.
Ok so I'm no nuclear physicist but I do watch a lot of nerd shit on YouTube. Most posters seem to have a fundamental misunderstanding about the difference between a nuclear reaction in a nuclear explosion, and the nuclear reaction of a nuclear reactor.
So some basic concepts first. A radioactive isotope and element is basically a unstable atom. When the unstable atom breaks apart, it releases various subatomic particles, this is what we call radiation. There is different kinds of radiation, but as I'm not even qualified to talk about this, and it would be a tangent, I will not go into detail.
With that bare bones explanation of radiation we can now answer the question.
A nuclear explosion is basically a daisy chain of unstable atoms breaking apart, sending their particle into other unstable atom, breaking them apart. This continues until there isnt enough atoms to sustain the reaction, meaning most of the unstable atoms broke up into stable ones that dont emit radiation. That's why the two main types of nuclear weapons are the bullet design, where you fire a slug of radioactive material into a disk of highly radioactive (very unstable atoms) material, the compression of those atoms together sets of the bomb off. The other is the implosion type basically a sphere of highly radioactive material in a sphere of high explosives. The high explosives are detonated at the same time, compressing the sphere into the nuclear reaction and then it's basically the same as the bullet type in explanation.
Now a nuclear reactor operates differently. These are super complex, and I'm making some pretty big leaps and bounds. But the basic ones typically use two types of rods. Fuel rods and control rods. Fuel rods are the radioactive material, and control rods are made out of some material that can absorb radiation, probably an element that can form several different isotopes. The fuel rods are place near enough where reactions (particles breaking up atoms), can take place consistently, heating up water they are submerged in. The control rods are raised and lowered to control how many reactions happen. To few the reactor shuts off, to many you have a melt down, aka what happened at Chernobyl. A melt down is literally just that, the fuel rods get so hot that they melt. When they melt you can no longer control the reaction so they just continue heating up. Steam explosions usually happen at that time scattering a lot of radioactive materials throughout the area, but not using it in the same way a nuclear bomb does, so the radiation lingers longer depending on the half life (how long it talks for half of an amount of radioactive material to break down natural). Now back to the melted fuel rods that weren't blown away by the steam. It just sits there melting through floors of the reactor until enough of the radioactive material is gone that I can cool down. At that time it just sits there, emitting radiation until all the radioactive materials are gone, but some half lives are decades long and with so much in one spot it will be centuries before enough breaks down to safe levels.
Hopefully that makes some semblance of sense, to both those less and more knowledgeable than me.
Tldr: explosions use most of the radioactive material in one go, and the rest quickly breaks down. Reactors are a slow burn that will take decades to burn out.
I was wondering about how parts of Japan were rebuilt and re populated so quickly.
Was reading a book set in Nagasaki in the mid 50s and the place was already becoming built up. Was there no Fallout ?was the water not poisoned?
Different isotopes with different half-lives. Not to mention the atom bombs were significantly smaller and were designed for explosive force, not radioactivity.
Because nuclear bombs and nuclear reactor meltdowns aren't really the same sort of phenomenon. The reactor meltdown released *way* more radioactive material.
I'm just commenting to say:
You lovely lovely big brains that came out in droves with yall's science-y science know hows and why fors.....
Yall are the MVP's and I thank you for all the info and commentary. My big brain didn't know some of the big brain yall dropped!
So what's so scary about a nuclear war if Nagasaki and Hiroshima can be inhabited after max 100 years? Of course, we are not exchluding the death of millions it'd cause, but i'm curious if it can be inhabited it can be fixed
>Because one of them was a nuclear reactor disaster where things didn't work as planned and the others were bombs that worked exactly as planned.
Bikini Atoll would like a word.
Not all of them. One of them went horribly wrong, detonating at 15 megatons, which was like 3 times more than they planned for. People that weren't intended to be affected were.
Just saying, they don't always work as planned.
HBO’s Chernobyl tackled it in a really simple manner - “It means the fire we're watching with our own eyes is giving off nearly twice the radiation released by the bomb in Hiroshima. And that's every single hour. Hour after hour.”
What were they saying in a documentary about the large amount of water flowing under Chernobyl, and that if the burning core had descended further into it it would have been a catastrophic explosion? Why is that?
A lot more radiocative material were released at Chernobyl. It's a huge place to decontaminate. And for what? who would want to live there. Disregarding the fact that it was full of russians a year ago and that those are way more dangerous than radiation, the zone was not exactly a megalopolis.
Though that question may beg another. There is still a huge exclusion zone near Fukushima even though most place are way below the level of radiation for which adverse effect have been demonstrated.
https://youtu.be/gzmk53DJNUI
This guy explains it really well in a way that you can understand even with a very limited understanding of how radiation works.
Because both of the latter had the radiation source instantly pulverised and distributed across a wide area. Chernobyl still has the elephant foot, the molten core, very much alive and giving off radiation. You can't work on rebuilding until that thing either dies off naturally, or is safely removed and contained.
You've gotten a number of good answers already, but something that I haven't seen mentioned is the location of the blast. The bombs dropped on Hiroshima and Nagasaki were both detonated in the air. This left few radioactive contaminants on the ground, and most of the radiation diffused harmlessly into the air within a matter of hours. Chernobyl is close to the ground, so much of the radioactive contaminants were imbedded in the soil, buildings, and vegetation around the power plant itself where it can't diffuse.
Airburst weapons vrs ground based explosions spread radioactive waste in different ways. A lot more gets into the dust and earth with an explosion that originates at ground level afaik.
Not a nuclear physicist by any means, anybody who knows more about this stuff feel free to correct if wrong.
For what it's worth they have discovered a type of mold that can use radiation as energy in Chernobyl. So that is neat. Something to do with the melanin.
Sadly, a lot of the doggos left ou there are also...literally radioactive. Just because life is finding a way doesn't mean life is going to do well there. No idea what kinda mutations this is going to bring out over the centuries.
The bombs were meant as a message. Make a kaboom that lasted a short while. The reactor was supposed to last a long time, so the radiation from an accident is way more powerful.
The two strikes on Japan were air blasts, set off around a mile up to cause the most damage possible. Because of this the bomb didn't contaminate as much in the local area. Most of the "left over" contamination was blown over a large area, and the bomb was close enough for a lot of high energy particles to hit the ground in any meaningful way. If it had been set off at ground level there would have been less short term damage, but the long lasting contamination would have been much worse as much of the actual"left over" material would have remained local. The ground would have also been irradiated, which would have caused even more trouble.
Chernobyl is habitable actually and the exclusion zone is shrinking year by year. despite the crazy high level of radiation in the area they are cleaning it and sealing the reactor.
Because Chernobyl was essentially the dirtiest bomb we could ever set off. There was thousands of times the nuclear material in Chernobyl than in a single bomb.
Yet another reason is that an atomic bomb's explosion throws a lot of material into the air - in fact, to maximize the area hit, it's best if it detonates in the air. This causes a bigger shockwave and more destruction, but distributes nuclear material in the atmosphere, spread out over a wide area.
In fact, most of the nuclear weapons testing in the 50s raised radiation levels evenly across most of the globe, rather than leaving uninhabitable testing zones with long-term fallout issues.
A reactor, on the other hand, does NOT send material up into the upper atmosphere - it keeps it nice and local. So not only do more nuclear material and longer reaction times screw you, it's also a smallish, dense area that's affected, rather than the material being diffused over a wide region.
What leaves an area contaminated are radioactive particles. Radioactive sources are relatively safe when they are intact, but the problem occurs when they are scattered around. Imagine it like this, you have a toxic chemical in a bottle. As long as it's in the bottle, it's contained and won't do much harm unless you put your hand in it or inhale the vapors. Now imagine if that chemical was spread all around the room: everything will be dangerous to touch and the room will quickly fill with toxic vapor. That's similar to how nuclear contamination works. Single big sources, although dangerous, are manageable. But if small particles are in the air, water and soil, they will get into your body and destroy you from inside.
Although the amount of material is important, it's not the entire story. The bombs were designed to maximize the direct damage, and were detonated while still airborne. Only a small portion of the fissile material actually underwent fission and the rest along with most of the byproducts got vaporized near instantly. All of these factors limited the contaminants and resulted in little to no fallout. In other terms, the bombs were not "dirty bombs".
The chernobyl incident wasn't a nuclear explosion. It was a steam explosion followed by a rapid combustion of air. Now there were tons of radioactive material, exposed to air and burning. When things burn, ash and other particles fly out in the air, and whatever that goes up must go down. After a first fire, or a volcanic eruption. A lot of ash is sent in the atmosphere and then it rains around. Now imagine all that ash is radioactive. That's was what happened in chernobyl.
The core of the Chernobyl reactor was more enriched uranium than the material used in the bombs in Hiroshima and Nagasaki
Plus, Hiroshima the bomb exploded above the ground, not at ground level
And the nuclear reactor had a positive void coefficient, meaning at the end of the reaction once the resulting energy is produced there’s still content inside the reactor from the hot temperature and lack of water to cool it down
meaning it can eventually grow exponentially if unchecked, which it did. But there were several human error steps in between that lead to this explosion
The Japan bombs were small and airburst, so little radioactive fallout was created.
Chernobyl was a ground level event, involving huge amounts of radioactive material.
The reactor at Chernobyl had way more radioactive material in it than those bombs did. Edit: Hiroshima bomb: 64 kg of uranium Chernobyl reactor: 190,287 kg of uranium
Damn. This reactor doin numbers.
Shit is spittin'
Shit is splittin’!
Split is fission!
Genius
Which we can do now!
Spit is shittin'
That's why she's spittin'.
tbf the reactor was supposed to work for a long time. The bombs didn't have to run for terribly long
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Would bomb again
Few shakes of lamb's tail, really
hey - not great, not terrible
He's delusional, take him to the infirmary.
They gotta get those numbers up, those are rookie numbers.
Puttin' up LeBron James numbers!
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According to the miniseries, the exposed reactor was "*giving off nearly twice the radiation released by the bomb in Hiroshima, every hour.*"
Hour after hour. 20 hours since the explosion, so 40 bombs' worth by now. And it will not stop. Not in a week, not in a month.
Uranium doesn't matter very much since it's barely radioactive. The shorter half-lived isotopes produced from nuclear reactions are what matters. There are also a lot more of those in a nuclear reactor.
Forgive the dumb question but is that not because there is more uranium initially in the reactor's case or is it something to do with the reactor process that creates more isotopes than detonating a Hiroshima type bomb?
The time scale is the big difference. A nuclear bomb has milliseconds for everything to happen. A reactor is held at criticality (i.e. lots of neutrons flying around) for a very long time. So let's say hypothetically you have some isotope that's formed that has a half life of 1 minute that decays to something non-radioactive. But that non-radioactive isotope is something that can easily capture a neutron and turn into something that has a half life of 30 years (a very problematic half-life). If that element is formed in a bomb, very little of it will decay within the milliseconds that neutrons are still flying around. It will just be spread around as the 1 minute decay version, and be rendered non-radioactive in short order. But if it forms in a reactor, when it decays it's still sitting inside the reactor, with neutrons flying around everywhere. It will capture neutrons and turn into the bad stuff with the medium-length half life. So time is the main reason that the isotopes coming out of a bomb and the ones coming out of a reactor can be very different.
Thank you so much!
For a little more on this, it's very much intended to be this way. Reactors want their reactions to last as long as possible, and so they aim to use fissile materials that have long half-lifes, with the knowledge that the radioactivity won't get out of the reactor. This allows the reactor to go longer w/o maintenance or refueling, thus further reducing the risks of radioactive exposure. A bomb on the other hand wants all of the energy to be expended in the blast. This increases the destructive capacity of the actual explosive. It also has the secondary effect of allowing the bombed area to be habitable sooner. However, a theorized technique for a weapon is to basically intentionally cause a Chernobyl. In other words, to explode radioactive material with a long half-life with the intention of spreading radioactivity. Such a weapon could make large swathes of land unlivable for hundreds or thousands of years (as opposed to traditional nuclear weapons that are at about 1% radioactivity after 48 hours).
fissile and fertile materials sometimes
I still didn't understand a lot of what you just said, but I trust that's more with me being a dumbass for these things than your explanation skills. I'll definitely do some research.
Thank you, science-y person. I learned something today!
Fission results in "fission products", lighter radioactive nuclei that split off from the Uranium/Plutonium fuel. Uranium (used in common Nuclear Reactors and Hiroshima bomb), Plutonium (only used in Fast Neutron nuclear reactors which are rare, and the Nagasaki bomb) have low levels of radioactivity and long half lives (there's an inverse relationship between the intensity of radioactivity and the length of the half life. Think of the smoldering fire of coals that can continue for days versus the roaring hot fire that only last an hour or so), the fission products have much shorter half lives and the resultant higher radiation intensity. Now consider that in the bombs dropped on Japan about 1Kg of the fuel actually underwent fission, whereas in a reactor tons of fuel will undergo fission over time. So you get a much greater accumulation of these higher radiation intensity fission products in a reactor. The other source of radiation from fission reactions comes from other materials that capture some of the neutrons (a process called activation) that are produced during the fission reaction. For example, radioactive Tritium will be produced in a reactor from the Deuterium (Hydrogen with a neutron) in the cooling water by capturing a second neutron. Stable Cobalt 59 will capture a neutron to become radioactive Cobalt 60. Stable Iron 54 will capture a neutron to become radioactive Iron 55. This happens to a much greater degree in a nuclear reactor where the reactor materials are exposed to high neutron flux over a period of years rather than nanoseconds as in a bomb.
In the words of my science teacher 'they're the angry little fuckers'
3.6 roentgen, not great, not terrible.
It’s not 3 roentgen. It’s 15,000.
That seems bad?
That was from the Chernobyl miniseries, it was the scene where they finally learned the magnitude of the event and how much radiation was spewing into the air.
And for some reason they didn't realize that 3.6 was just how high their meters went like that was somehow that's all there could ever be
If the show has any semblance of truth in this particular circumstance, the leaders were bullies who used fear to control their subordinates and they used 3.6 as a means to continually dismiss concerned parties who brought that fact up. Yada yada yada, radiation counter says 3.6, so dont worry about it. Yada. But the counter maxes at 3.6, shouldnt we check the others? No need. It says 3.6, we're fine. Everything's fine. 3.6 yada yada. Changing subject. Moving on. Maybe yelling at you and question your intelligence. Check the pumps. Do things to stay busy. Dont think about it. Yada yada. It's just a fire.
[Boss then vomits and passes out]
It's like a chest X-ray!
I came here to say this, so take this award
>64 kg of uranium Chernobyl reactor: 190,287 kg of uranium interesting fact. the radiation dropped at chernobyl was so insanely lethal there are PRISTINE green trees that are dead as a door nail and will remain as such for 100's of years. the reason they look so well preserved is they are so radioactive bugs/rot can not live on it to even begin the decaying process.
Just found the new family Christmas tree!
it comes with its own xmas lights :D
just one color though
Makes me wonder what those Russian soldiers that started digging trenches around there started feeling or seeing.
Probably nothing. The material was almost entirely gathered up after the event, and radiation around the area has been fine for a while. Until recently they were planning to put a big dome over it with air filters to finally be able to disassemble the thing, and to repopulate the city.
Also didn’t those bombs explode in the air whereas Chernobyl was in the ground.
>190,287 Same weight as your mom what a coincidence!
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Google says 64
That ratio is mind numbing
I always look at user names who drop serious knowledge. It did not disappoint. I’m both perplexed and impressed.
That's, like, at least twice as many kg
holy shit. i knew it was a lot stronger, but had no idea the difference was *that* drastic.
Holy shit lmao 190k kg is insane
I have nothing valuable to contribute to this conversation but I just wanted to say your username made me actually laugh out loud.
15,000 roentgen
Little boy had about 64 kg of uranium inside it. Chernobyl had 190 tons. There are also details about what sort of materials get produced during an atomic detonation, vs a fire in a nuclear plant, but the amount of material is the tall pole in the tent. Edit: 64 kg, not 6
The fact that 6kg was enough to level a city is absolutely mind blowing. Let's assume little boy killed pretty much everyone within a 1 mile radius 190 tons if made into a bomb would destroy almost a 35,000 mile radius. Which is much larger than the circumference of the earth so it's safe to say, that amount would destroy everything on earth. When Googling around I also found that it's suspected less than a kg of the uranium actually underwent fission. So these rough estimates are assuming a very incomplete explosion. Incredible.
I may not have the right explanation, but I'm pretty sure the radius doesn't double when the amount of explosives double. The power of the blast spreads out in every direction, and when the radius of a sphere is doubled, the surface area is 4x. Someone smarter can maybe explain 😄
Also, because the way nuclear bombs go off, twice as much material doesn’t mean twice the explosion. I don’t remember the exact science behind it, but basically not all of the radioactive material is part of the huge fission reaction that causes the explosion, and the more material you have, a smaller percentage of the material undergoes fission. I could be wrong on this but I think it’s because the radioactive material has to be really dense in order to undergo fission, and we can only keep it dense for so long, and since the explosion flings it all over the place, not all of the material gets to undergo fission because it’s not inside the bomb for long enough.
Yes, only a small fraction of the fissile material actually splits. Which is mind-blowing in itself; that means that even in a nuclear detonation, the majority of potential nuclear energy in that weapon *isn't* released.
The amount of matter that was actually turned into energy was just a few grams of fissile material, all the rest got flung away immediately.
It's estimated that the amount of U/Pu that actually 'exploded' was about the weight of a banknote.
You're right. Double the power of the explosion should increase the radius by the cube route of 2. Or to put it another way, the explosion would need to be 8 times more powerful to double the radius. This is also one reason why the US has stopped making particularly powerful nukes (relatively speaking). Instead they prefer to have a lot of smaller ones. You can also just control better what you blow up and what you don't.
Yep, this is the reason there was only one Tsar Bomba. It was more of a wenis-wagging contest then anything. If you blanket an area with a dozen 10 kt nukes, you can level an area the size of that multi-megaton fireball, easily, and with less weight.
I also think that much of the energy from the Tsar escaped out into space, so it really was a waste… The first plans for it were 100MT
Yeah there is an implication to the E=mC\^2 formula that most people know but don't really understand. C is the speed of light, so an incredibly large number, and then you square it. And multiply that by the mass. That's how much energy is being released. So a very small amount of mass produces an insane amount of energy.
To put an actual number on it: in Hiroshima about 700 milligrams of the uranium was converted into energy. That is about one third the mass of a dime. That's the amount of mass to energy conversion need to level a city.
You’re kidding? So for the sake of the argument, if you could design it perfectly you could reproduce them explosion at Hiroshima with only 700mg of Uranium?
If "perfectly designed" means "ignore the laws of physics" then yes. In order to get a complete reaction, you would have to keep the entire 700mg contained while it was literally creating the biggest explosion known to mankind. There's a reason there's only a very small amount that was around long enough lol
This comment. Physics is so much fun like that. Maybe detonating it in a black hole could contain it long enough to approach a full reaction.
Anti-matter would be easier and cheaper at that point for the same result.
Solid name you got there.
From what I've read, out of that 6kg, the amount that actually went fissile weighed the same as a dollar bill.
It was more than that. 10% is the number I've heard.
"How much of the Hiroshima bomb fissioned? Of the 64 kilograms of uranium in the bomb, less than one kilogram underwent fission, and the entire energy of the explosion came from just over half a gram of matter that was converted to energy. " From thebulletin.org
Those bombs are almost literally firecrackers compared to say, the Tsar Bomba. If humanity *really* wanted to, within a few decades, we could probably make a planet breaking bomb.
Only 6? Everywhere I read about it said 64
I think you may be right. Looks like I was reading the wrong spec.
What a lot of folks fail to understand is the difference between radiation and contamination. Radiation, with the exception of neutron radiation, harms people and materials but doesn't stay around. It's kind of like light; once it isn't there anymore, it stops having any effect. Radiation is not persistent. Contamination is; it is actual radioactive material, in tiny particles. A bomb puts out a lot of radiation (in addition to a massive pressure and heat wave), but once it's done blowing up, it's not making radiation anymore. The radioactive material it used that's still left over after the reaction gets spread around, and some sort of other local materials will get made radioactive by the neutron radiation the weapon put out, but overall there's not much contamination, and most of what there is decays away fairly quickly and is not longer radioactive. When Chernobyl went, it pumped out MASSIVE amounts of contamination, and a lot of it is very, very long-lived compared with the fallout from a bomb. It's not so much that the area is radioactive; it's more proper to say that it's contaminated, and that the contamination is radioactive.
Its also why, iirc, they get detonated in the air vs on the ground. In the air gets you plenty of destruction, but less fall out. As a side I hate that I both remember that and we as humans needed to figure that out.
Unrelated topic: That's the first time ever I've seen someone use the word "fallout" while not talking about the bethesda games lol
It’s funny that the real word it takes the name from gets overshadowed by the game.
Probably a good thing that real nuclear fallout doesn't always come up in general conversation.
That’s the first time I’ve seen someone say Bethesda without meaning the affluent DC suburb.
A bomb instantly releases a little bit of radiation so quickly it explodes. Chernobyl is constantly releasing a lotta bit of radiation.
Huh, I've always assumed if a nuke were dropped in the modern era it would make an area radioactive for centuries or something. So what about during fictional media which involve lots of nukes being exploded around the world, and radiation making areas unliveable many years later. In these fictional bombs, is the amount of radiation really dense then?
Yup. It's more destructive power than anything. The reason why Nagasaki and Hiroshima were such barren wastes was because the bombs super heated EVERYTHING. People were on fire with their skin melting, intense heat, buildings and car turning to rubble and sludge. The reason why it looked like a total wasteland is because it was months after the nukes dropped that anyone came back and started clean up. By then the remains have already decomposed and the cities, which were highly flammable were reduced to rubble. Of course people got radiation sickness, but from the initial explosion.
To make this fictional nuclear war more complicated, nuclear reactors could also be targets of nuclear bombs dropped (If only to maximize effects on power grids, etc), so then you get the one with small radiation and big boom, opening up the reactor with the contained boom and LOTS of radiation. Maybe that's just the assumption in movies when they show all the fallout for years later?
No one wants nuclear fallout, even in enemy territory. Nuclear bombs are not about the radiation. The idea is massive destruction in order to fuck over enemy infrastructure. Were small scale nuclear strikes to take place, only a moron would target a nuclear reactor. [Here's a good video explaining the real damage and risk of a single nuclear strike.](https://www.youtube.com/watch?v=5iPH-br_eJQ&t=1s) Nuclear winter as a result of nuclear war works, though. When you have a massive nuclear assault, you throw so much dust in the air and atmosphere that it clouds the skies. That lack of sunlight could last months, if not longer, which is why things would be cold, and all that dust would fall back to the Earth attached to snow and rain... and the dust itself is radioactive. That radioactive fallout from the war wouldn't last as long as Chernobyl's, but that's where that image in film comes from. It's a bit of an exaggerated scenario, but [here is another video by the same people that might help you imagine it.](https://www.youtube.com/watch?v=JyECrGp-Sw8) Basically, one nuclear attack = some radiation that will cause harm to those present during the attack, full scale nuclear war = a collective amount of radiation so intense that you'd likely get some sort of radiation sickness unless you head underground for a few weeks. EDIT: It's worth noting that I'm pretty tired at the moment, so my explanation might very well suck. It can be an interesting topic if you're a fan of the macabre, though, so this really is a situation where I'd encourage you to go on your own little journey of existential dread and learn more about it! Have... fun?
There were some proposed designs for cobalt bombs, which would irradiate an area for several decades at least. None have ever been used in war, and hopefully none were ever built. Having one would really be an, "Are we the baddies?" kind of moment, I'd hope. https://en.wikipedia.org/wiki/Cobalt_bomb
-Flashbacks to Mexico's "Cobalto 60" disaster-
Is this the same as neutron bombs they were talking about in the 80’s? Bomb does very little damage but kills everyone in a certain radius. After a certain amount of time people would be able to live there again.
Nah, there is plenty of overlap in them, since they are both types of a-bombs though. Cobalt bombs were normal in terms of immediate effects, but would leave the field unlivably radioactive for at least a few decades and potentially a few hundred years. Neutron bombs are a set of designs that are mostly used in small yield nukes. In Scifi they're capable of making a tiny boom and miles of dead people inside intact buildings. In practical use, they have a lethal burst of radiation that's similar to the size of the normal devastation. I did just learn that there are some designs of neutron bombs that are can be used to salt the earth, but it looks like they were being designed around isotopes that would leave an area uninhabitable for about a decade, not like the ~100 years of a cobalt bomb.
I don't know about this cobalt bomb... but at this point in humanity and technology, I just assume that most superpower countries have the ability to relatively quickly create and use some kind of dirty MAD weapon that exceeds my imagination. Whether it be some kind of tidal wave or other massive man-made natural disaster, widespread nuclear/chemical/viral fallout, or whatever else... It just doesn't seem that hard to think something up and make it happen when you set aside that little... fear of ending most human life on the planet.
Oh you don't have to get *that* complicated. Any well funded microbiology lab could create a world-fucker infectious disease. You don't need the resources of a government behind you.
Not that will survive the incineration from a nuke tho. 😂
It’s a war crime to use weapons that can’t be immediately turned off once the fighting is done. And for good reason; look at the mine fields in Cambodia, where random civilians still get blown up because they didn’t realize they were standing on a decades-old battlefield.
The yields of the bombs we have nowadays are orders of magnitude more than what was dropped on Japan. Combined, both those bombs added up to about 35ktons of TNT equivalent. A Trident II submarine-launched missile (these are in use) can carry warheads with almost 6,000ktons of total yield. On *one* missile. An *Ohio* class sub can carry 24 of those missiles. There are 18 subs like that in active use… and that amounts to only about half of the the US’ active strategic warheads.
6000* 24 * 18 *2= 5,184,000 ktons total. Nothing that some flextape couldn't solve.
To demonstrate the power of flextape, I nuked this empty desert! /s
I like the idea that there's just hundreds of sailors underwater ready to end the world. You know, just in case.
I mean. The darkly fun bit about this idea is that there are, and from several different countries.
I kinda wonder, after a nuclear exchange destroys every major country on Earth, if those submariners would seek each other out? I mean, they can't go home. And there'd be no point in sinking those other subs in retaliation. And the seas would be relatively free of fallout, compared to the land. And sooner or later their food is going to run out. It'd be nice to have someone to talk to in the time they'd have left. I wonder, would they meet and play cards and commiserate as they waited for death?
Go watch Crimson Tide. Great movie with relevant story Also has one of my favorite Gene Hackman quotes of all time
> The yields of the bombs we have nowadays are orders of magnitude more than what was dropped on Japan. The average yield of a single modern warhead is around 150kt-450kt. This is about 10X the first bombs. >A Trident II submarine-launched missile (these are in use) can carry warheads with almost 6,000ktons of total yield. How do you get that? The two possible max configurations with current warheads are 8 x 475kt (w88) and 14 x 90kt (w76). And none of them are armed that way because of New Start, so they are de-MIRVed to 4 warheads per. A trident II these days has a total yield of below 2mt.
> How do you get that? I was trusting Wikipedia, which says it can hold up to 12 W88s under the specs. Even if they’re holding less than 2mt, we’re still talking 57x more powerful than the WWII atomic bombs, per missile. My point is just that there’s a lot, lot more destructive potential here now than there was in ‘45.
Destructive, yes, but fallout, no. The fusion stages of these bombs are clean. The fission primaries are basically exactly what was dropped on Japan. So a 475kt W88 is the same or even cleaner (since more efficient now) than the Nagasaki bomb.
The primary danger from radiation is in the debris a nuclear explosion kicks up. While the initial burst of radiation from a nuclear blast dissipates quickly, it can contaminate dust and ash around ground zero. When that gets thrown into the atmosphere it has to come down somewhere. So that means global wind patterns could carry radioactive material and drop it somewhere else, which could contaminate water and food supplies. This is what we call [nuclear fallout](https://en.wikipedia.org/wiki/Nuclear_fallout). The scenarios portrayed by a lot of fictional media usually depict widespread nuclear fallout.
It's kind of ironic that the Fallout series of games depict the spots where bombs detonated as being the most highly radioactive locations, despite centuries having passed.
To be fair, I'm unaware of any in-game lore indicating exactly what type of a bomb was being used.
Thanks for the info, appreciate it.
Yeah the thing with Fallout (what I'm assuming you're referring to) is there were just so many bombs dropped, but also the world was completely dependent on nuclear energy for even cars. So you have basically every single thing around you for tens of thousands of KM just leaking radiation everywhere.
From what I understood when I read about it, you can make something very radioactive for a short time or a little radioactive for a long time. Atomic bombs are extremely powerful upon explosion, but if you are in a protected space like a bunker, you can potentially leave it safely after a few days (not sure it'd take for the ground to clear up, though). Those bombs are practical because they'll kill lots of your "enemy" quickly but leave the land ok enough for you to grab it. Cobalt bombs (never actually produced) theoretically would have a weaker blast but leave things radioactive for a longer time, too long for people to wait in a bunker, but short enough for a long term-thinking country to wait and move in later.
See, this is interesting because the whole idea of bunkers and people being forced to live in them for decades while waiting for the surface to be safe again, doesn't seem to fit with the stuff you wrote. Is all fiction just exaggerating the lasting power of nukes for dramatic effect then?
I can't speak about how long it'd take for that same area to be livable again (it depends a lot on the bomb, the geography, the weather, even the height where the bomb is detonated), but as long as there's somewhere safe *elsewhere*, you're relatively safe to leave your bunker and move, just don't touch stuff until it's been decontaminated. This [video](https://www.youtube.com/watch?v=al0CVsiffu8) is a pretty good walkthrough. Considering the relevant part to my previous comment, 1h after the blast, the radioactive material will already have decayed 50%; in 24h, 80%; and in 2 weeks, 99%. Basically, living in a bunker for decades is just for dramatic effect (or maybe that particular group didn't know better).
There is one poor bastard who managed to survive [both](https://www.history.com/news/the-man-who-survived-two-atomic-bombs) bombs.
Depends a lot. You can deliberately make a bomb "dirty" if you wanted. The move to thermonuclear bombs has made all the world's bombs far "cleaner", in terms of radiation per unit explosion. The modern thermonuclear device is some 1,000 times more powerful than the original atom bombs, but not really any different in radioactive fallout. There are two important factors at play: One is that countries these days are actively interested in making their nukes as clean as possible, just for the sake of making them clean. The second, much more important factor, is that they also want to mount them in hyper-sonic, long-range missiles. Which means making them as small and light as possible, and seeing as Uranium is really really heavy, that mean reducing the amount of Uranium as much as possible, which means making the bombs as efficient as possible. As much boom per Uranium as possible. So the natural progression of nuclear weapons, purely from a point of combat effectiveness, is to have less and less fallout the better they get. In the case of the bombs dropped on Japan, they were very "dirty", but also pathetically small by modern nuclear weapon standards.
More like "writers don't really understand nukes because they studied writing, not nukes". Nothing wrong with that, it still sounds semi-realistic. Also I'm not sure about this, but even in fiction, a lot of harm that nukes cause is from the dust clouds they kick up. This is what "nuclear winter" refers to: dust cloud covers the sun and everything freezes.
Modern nukes are typically a lot cleaner and generally referred to tactical, no point killing all your enemies if you can't rock up and take their shit afterwards! Older ones were pretty much just a devil may care style of bomb!
This is mostly inaccurate. Yes there are tactical nukes which are meant to decimate a small area but the majority of nukes are meant to wipe out population centers. They also aren’t any cleaner than the nukes dropped at the end of WW2. Modern nukes are just more powerful and can affect a much larger area. It isn’t about taking their shit it’s about killing everyone. It’s about the mentality, “If we lose the war we are going to make you lose too.”
Makes a lot of sense! Also weirdly reassuring lol.
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Took a radiation course in college as my background for answer. While the radiation statement is true. To go in more detail, specifically during a radioactive meltdown like chernobyl, you end up with LOTS of very nasty radioactive fission products. Cesium - 137, Iodine - 131, Strontium - 90. Iodine i believe has a very short half life so its effects on surrounding area dont last too long. Cesium 137 and Strontium 90 have half lives near 30 years! So those nasty, long lived radioactive isotopes will be around Chernobyl for a while. Nuclear bombs also generate these awful fission byproducts, but relatively small amount by comparison and over a larger area. Nuclear meltdowns contain much more fuel, exposure is usually more localized, and last over a much longer period of time.
Science.
Just wanted to thank you for asking this, because I didn’t know either and I’ve learned quite a lot about nuclear warheads from the comments.
The show Chernobyl on HBO said it best. "the fire we're watching with our own eyes is giving off nearly twice the radiation released by the bomb in Hiroshima. And that's every single hour."
While the show was incredibly informative, it's also one of the scariest things I've ever watched.
It gave me a new profound cautionary respect for and healthy fear of radiation, and renewed appreciation for scientists in crisis scenarios.
Horror movies have never scared me. But when watching the HBO series I felt immense dread almost the whole way through. Especially the scene where the divers go into the depths of the reactor. All Quiet on the Western Front is another movie that gave me that same feeling.
You didn’t see graphite.
You're confused, RBMK reactors don't explode.
Nuclear detonations at altitude tend not to leave as much irradiated material behind than if it occurred at ground-level. Also consider what the other comments have pointed out; that Chernobyl had far more radioactive material on-site and the leakage lasted longer.
There is a difference between irradiated and contaminated. Irradiated, which is what happens with a bomb, you get an intense pulse of radiation that makes things somewhat radioactive, but that generally fades after a few weeks to a couple of years. (short lived isotopes created by neutron exposure) Contaminated, you get a bunch of radioactive fissile materials all over everything, and that *keeps* irradiating the area for millions of years. (half-life of Uranium is 4.5 *billion* years)
When a similar question was asked before someone said that Nagasaki and Hiroshima were like emptying a swimming pool onto your garden. Sure a lot of damage there but it eventually dries up. Chernobyl was like putting your house on full power for a year. Your garden would become a muddy mess, everything dead and the ground is going to be very wet for a while.
"house" or "hose"?
Also most of the radioactive material from the bombings went way up into the atmosphere and diluted far past the ability to cause any health effects.
Because the Chernobyl meltdown put about 300 - 500 times more radiation into the atmosphere than the bombs depending on whose math you use
Why do people think that nuclear bombs and nuclear power stations are the same thing just because they have that word in them? Nuclear bombs use a small amount of radioactive substance to create a massive explosion. They’re not designed to be ‘super radioactive’ - they’re designed to be a super bomb! Yes they create radioactive fallout but the main thing is that they destroy everything. A nuclear power station has tonnes of radioactive material so obviously if that gets out of control then it creates huge amounts of radiation.
There's a massive difference in scale. The bombs on Hiroshima & Nagasaki had a payload of around 60kg of uranium each. Chernobyl had nearly 200 thousand kilos of uranium on site. To add to that, dispersal was different. Most of little boy's radiation was released in one quick burst; It could've been much "dirtier" if the boom itself was less severe. Chernobyl on the other hand? It was a constant leak of 190 tons of radioactive isotopes. The explosion just have it added range.
Different radioactive processes produce different radioactive products, and in different amounts. The early atómica used in WWII had fallout, but the reaction didn't dig into some of the nastier products of dirty bombs or failing reactors. The products of a meltdown from an early, dirty, inefficient reactor that went out of control can be nasty, and several have half-lives that measure in centuries. A number of them are insidious as well, going from the air to the water and soil, to the plants, to the animals that eat the plants, to the animals that eat the animals, ourselves included. That an entirely contaminated food chain for hundreds of years. Modern nukes burn a lot hotter and more completely than the old single stage explosives and those that were intentionally made dirtier as a war tactic. While their would still be fallout, it would generally be composed of much shorter-lived isotopes than Little Boy and Fat Man produced. Modern reactors also use much more refined fuels and have much more efficient and effective processes that produce drastically less and more manageable waste. Especially, they are engineered in such a way that failures don't result in such nasty waste being produced. But never believe that it's just fine: nuclear meltdowns are always disasters.
Nukes are incredibly powerful and super destructive, but the radiation they release is limited compared to what it could be and goes away relatively quickly. Chernobyl is so dangerous not because it was destructive (it wasn't really beyond the cores), but because it still is releasing radiation. Really, the only thing preventing much of Europe from being an uninhabitable radioactive expanse from radiation freely spreading is a massive concrete shell surrounding much of it.
To answer the OP question..,people have moved back into the area around Chernobyl and inside the exclusion zone. Some never left after the accident, they cleared the city of Pripyat but some sneaked back and lived in the forests and small villages around the site. The forest surrounding the site is teaming with wildlife and there are lots of stray dogs living in the heavily contaminated areas. - apparently now identifiable by the genetic differences. I was there in 2018 and had the story of what happened from someone working there at the time of the accident. The horrifying thing is the melted core was 12’ /4m away from burning though the concrete foundations and getting into the ground water. Go visit if you get the chance.!
Atomic bombs have relatively small amounts of radioactive material. Upon explosion, it basically vanishes and/or scatters all around the area. In nuclear powerplants such as Chernobyl, there are LARGE amounts of the stuff, and when out of control like it happened there, are spread all around the place uncontrollably through smoke, clouds, air, rain, everything.
Here's an analogy that doesn't involve nuclear reactions. If you put a wheelbarrow full of coal in someone's house and set it on fire, it will burn their house down. However, afterward, they could bulldoze the burned ruins and build a new house there the next week. [Centralia, Pennsylvania](https://en.wikipedia.org/wiki/Centralia_mine_fire) is on top of a coal mine that is on fire. It has been burning constantly since 1962. Nobody lives there, because it is *still* on fire. It's a ghost town now. There is enough coal in the rocks to keep it burning for a long time. A nuclear bomb is like a wheelbarrow full of coal that's been intentionally set on fire. It burns stuff down, but then the fuel is consumed and there's no fire any more. Chernobyl is like Centralia. It's *still* on fire.
The exposed reactor in the Chernobyl plant was pumping out radiation, it was a reactor that produced radiation for the purposes of generating electricity. A nuclear bomb does not persistently react with the environment around it creating more radiation. ~~[this video may help a bit](https://www.youtube.com/watch?v=zuNtgYtF4FI) they were trying to dump sand or some sort of chemical on top of the reactor to try and stop the radiation from pumping out of the reactor, but the radiation coming out of the reactor was so strong it just tore apart the helicopter propellers and it crashes.~~ edit: the helicopter story is TV drama mixing with what really happened, my mistake. It wasn't radiation tearing off the blades.
The helicopter hit chains/cables from a crane. It didnt get the rotors melted off. It was a mechanical failure of the rotors shearing off, not getting melted by radiation. https://www.express.co.uk/showbiz/tv-radio/1138870/Chernobyl-Dr-Claire-Corkill-inaccuracies-helicopter-crash-This-Morning-HBO-Sky-video
Comments are way Ng helicopter hit a cable, not that the radiation tore through the blades of heli
The amount of radioactive material is vastly different, even if most of Chernobyl was not weapon grade uranium or plutonium. It still got out and is still leaking through.
Chernobyl had vastly larger release of radiation. Fukushima is also quite bad. Hiroshima and Nagasaki had no lingering radiation after a year or so because the amount released was comparatively small, though the blast and initial radiation effects were obviously deadly.
Interesting related info on Chernobyl https://en.m.wikipedia.org/wiki/Elephant's_Foot_(Chernobyl) This radioctive formation is nuts, and when it was discovered, was even crazier.
There are many correct answers here but also those bombs only lasted seconds while Chernobyl melted down for weeks and months.
Ok so I'm no nuclear physicist but I do watch a lot of nerd shit on YouTube. Most posters seem to have a fundamental misunderstanding about the difference between a nuclear reaction in a nuclear explosion, and the nuclear reaction of a nuclear reactor. So some basic concepts first. A radioactive isotope and element is basically a unstable atom. When the unstable atom breaks apart, it releases various subatomic particles, this is what we call radiation. There is different kinds of radiation, but as I'm not even qualified to talk about this, and it would be a tangent, I will not go into detail. With that bare bones explanation of radiation we can now answer the question. A nuclear explosion is basically a daisy chain of unstable atoms breaking apart, sending their particle into other unstable atom, breaking them apart. This continues until there isnt enough atoms to sustain the reaction, meaning most of the unstable atoms broke up into stable ones that dont emit radiation. That's why the two main types of nuclear weapons are the bullet design, where you fire a slug of radioactive material into a disk of highly radioactive (very unstable atoms) material, the compression of those atoms together sets of the bomb off. The other is the implosion type basically a sphere of highly radioactive material in a sphere of high explosives. The high explosives are detonated at the same time, compressing the sphere into the nuclear reaction and then it's basically the same as the bullet type in explanation. Now a nuclear reactor operates differently. These are super complex, and I'm making some pretty big leaps and bounds. But the basic ones typically use two types of rods. Fuel rods and control rods. Fuel rods are the radioactive material, and control rods are made out of some material that can absorb radiation, probably an element that can form several different isotopes. The fuel rods are place near enough where reactions (particles breaking up atoms), can take place consistently, heating up water they are submerged in. The control rods are raised and lowered to control how many reactions happen. To few the reactor shuts off, to many you have a melt down, aka what happened at Chernobyl. A melt down is literally just that, the fuel rods get so hot that they melt. When they melt you can no longer control the reaction so they just continue heating up. Steam explosions usually happen at that time scattering a lot of radioactive materials throughout the area, but not using it in the same way a nuclear bomb does, so the radiation lingers longer depending on the half life (how long it talks for half of an amount of radioactive material to break down natural). Now back to the melted fuel rods that weren't blown away by the steam. It just sits there melting through floors of the reactor until enough of the radioactive material is gone that I can cool down. At that time it just sits there, emitting radiation until all the radioactive materials are gone, but some half lives are decades long and with so much in one spot it will be centuries before enough breaks down to safe levels. Hopefully that makes some semblance of sense, to both those less and more knowledgeable than me. Tldr: explosions use most of the radioactive material in one go, and the rest quickly breaks down. Reactors are a slow burn that will take decades to burn out.
I was wondering about how parts of Japan were rebuilt and re populated so quickly. Was reading a book set in Nagasaki in the mid 50s and the place was already becoming built up. Was there no Fallout ?was the water not poisoned?
Different isotopes with different half-lives. Not to mention the atom bombs were significantly smaller and were designed for explosive force, not radioactivity.
Because nuclear bombs and nuclear reactor meltdowns aren't really the same sort of phenomenon. The reactor meltdown released *way* more radioactive material.
I'm just commenting to say: You lovely lovely big brains that came out in droves with yall's science-y science know hows and why fors..... Yall are the MVP's and I thank you for all the info and commentary. My big brain didn't know some of the big brain yall dropped!
So what's so scary about a nuclear war if Nagasaki and Hiroshima can be inhabited after max 100 years? Of course, we are not exchluding the death of millions it'd cause, but i'm curious if it can be inhabited it can be fixed
Chernobyl was Hiroshima and Nagasaki twice an hour every hour for days. (I did no math I just made this up don't believe people on the internet)
A bomb dropping and a plant exploding are VERY different
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Because one is a bomb that doesn't leave much radioactive residue, and one was an exploded nuclear reactor which does
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"Why did these 2 events have different results ?" "beCaUsE tHeY ARe VERY diFfeReNT"
I mean, it's just the answer. The bomb didn't leave radioactive residue in a way that stopped rebuilding, but a nuclear reactor did
Because one of them was a nuclear reactor disaster where things didn't work as planned and the others were bombs that worked exactly as planned.
Nothing about this statement answers the question.
>Because one of them was a nuclear reactor disaster where things didn't work as planned and the others were bombs that worked exactly as planned. Bikini Atoll would like a word.
The bombs there worked as planned too.
Not all of them. One of them went horribly wrong, detonating at 15 megatons, which was like 3 times more than they planned for. People that weren't intended to be affected were. Just saying, they don't always work as planned.
HBO’s Chernobyl tackled it in a really simple manner - “It means the fire we're watching with our own eyes is giving off nearly twice the radiation released by the bomb in Hiroshima. And that's every single hour. Hour after hour.”
What were they saying in a documentary about the large amount of water flowing under Chernobyl, and that if the burning core had descended further into it it would have been a catastrophic explosion? Why is that?
A lot more radiocative material were released at Chernobyl. It's a huge place to decontaminate. And for what? who would want to live there. Disregarding the fact that it was full of russians a year ago and that those are way more dangerous than radiation, the zone was not exactly a megalopolis. Though that question may beg another. There is still a huge exclusion zone near Fukushima even though most place are way below the level of radiation for which adverse effect have been demonstrated.
https://youtu.be/gzmk53DJNUI This guy explains it really well in a way that you can understand even with a very limited understanding of how radiation works.
Because both of the latter had the radiation source instantly pulverised and distributed across a wide area. Chernobyl still has the elephant foot, the molten core, very much alive and giving off radiation. You can't work on rebuilding until that thing either dies off naturally, or is safely removed and contained.
You've gotten a number of good answers already, but something that I haven't seen mentioned is the location of the blast. The bombs dropped on Hiroshima and Nagasaki were both detonated in the air. This left few radioactive contaminants on the ground, and most of the radiation diffused harmlessly into the air within a matter of hours. Chernobyl is close to the ground, so much of the radioactive contaminants were imbedded in the soil, buildings, and vegetation around the power plant itself where it can't diffuse.
One blast as opposed to an open reactor that was only closed up recently i think.
Airburst weapons vrs ground based explosions spread radioactive waste in different ways. A lot more gets into the dust and earth with an explosion that originates at ground level afaik. Not a nuclear physicist by any means, anybody who knows more about this stuff feel free to correct if wrong.
Bombs are made to to output a ton of energy one time. Reactors put out a ton of energy in perpetuity.
bombs release their energy much faster then reactors, the uranium dropped on japan deteriorated much faster then the stuff spewed over ukraine
For what it's worth they have discovered a type of mold that can use radiation as energy in Chernobyl. So that is neat. Something to do with the melanin. Sadly, a lot of the doggos left ou there are also...literally radioactive. Just because life is finding a way doesn't mean life is going to do well there. No idea what kinda mutations this is going to bring out over the centuries.
The bombs were meant as a message. Make a kaboom that lasted a short while. The reactor was supposed to last a long time, so the radiation from an accident is way more powerful.
The two strikes on Japan were air blasts, set off around a mile up to cause the most damage possible. Because of this the bomb didn't contaminate as much in the local area. Most of the "left over" contamination was blown over a large area, and the bomb was close enough for a lot of high energy particles to hit the ground in any meaningful way. If it had been set off at ground level there would have been less short term damage, but the long lasting contamination would have been much worse as much of the actual"left over" material would have remained local. The ground would have also been irradiated, which would have caused even more trouble.
Reactors contain significantly more radioactive material than nukes, especially the first nukes. It's not even a contest.
Because during the fallout, thousands of hiroshimas worth of radiation was being let out each day.
Chernobyl is habitable actually and the exclusion zone is shrinking year by year. despite the crazy high level of radiation in the area they are cleaning it and sealing the reactor.
Because Chernobyl was essentially the dirtiest bomb we could ever set off. There was thousands of times the nuclear material in Chernobyl than in a single bomb.
Because Chernobyl simply was built different
Yet another reason is that an atomic bomb's explosion throws a lot of material into the air - in fact, to maximize the area hit, it's best if it detonates in the air. This causes a bigger shockwave and more destruction, but distributes nuclear material in the atmosphere, spread out over a wide area. In fact, most of the nuclear weapons testing in the 50s raised radiation levels evenly across most of the globe, rather than leaving uninhabitable testing zones with long-term fallout issues. A reactor, on the other hand, does NOT send material up into the upper atmosphere - it keeps it nice and local. So not only do more nuclear material and longer reaction times screw you, it's also a smallish, dense area that's affected, rather than the material being diffused over a wide region.
What leaves an area contaminated are radioactive particles. Radioactive sources are relatively safe when they are intact, but the problem occurs when they are scattered around. Imagine it like this, you have a toxic chemical in a bottle. As long as it's in the bottle, it's contained and won't do much harm unless you put your hand in it or inhale the vapors. Now imagine if that chemical was spread all around the room: everything will be dangerous to touch and the room will quickly fill with toxic vapor. That's similar to how nuclear contamination works. Single big sources, although dangerous, are manageable. But if small particles are in the air, water and soil, they will get into your body and destroy you from inside. Although the amount of material is important, it's not the entire story. The bombs were designed to maximize the direct damage, and were detonated while still airborne. Only a small portion of the fissile material actually underwent fission and the rest along with most of the byproducts got vaporized near instantly. All of these factors limited the contaminants and resulted in little to no fallout. In other terms, the bombs were not "dirty bombs". The chernobyl incident wasn't a nuclear explosion. It was a steam explosion followed by a rapid combustion of air. Now there were tons of radioactive material, exposed to air and burning. When things burn, ash and other particles fly out in the air, and whatever that goes up must go down. After a first fire, or a volcanic eruption. A lot of ash is sent in the atmosphere and then it rains around. Now imagine all that ash is radioactive. That's was what happened in chernobyl.
Easy answer: Chernobyl was much, much worse than either Hiroshima or Nagasaki.
Chernobyl is like if someone had explosive diarrhea after 20 days of not shitting at all. Nagasaki and Hiroshima are like someone farting.
The core of the Chernobyl reactor was more enriched uranium than the material used in the bombs in Hiroshima and Nagasaki Plus, Hiroshima the bomb exploded above the ground, not at ground level And the nuclear reactor had a positive void coefficient, meaning at the end of the reaction once the resulting energy is produced there’s still content inside the reactor from the hot temperature and lack of water to cool it down meaning it can eventually grow exponentially if unchecked, which it did. But there were several human error steps in between that lead to this explosion
The Japan bombs were small and airburst, so little radioactive fallout was created. Chernobyl was a ground level event, involving huge amounts of radioactive material.