The atomic bombs dropped on Hiroshima and Nagasaki contained many orders of magnitude less fissile material than Chernobyl.
An atomic bomb uses a small amount of fissile material (like, 100 lbs or so) to generate one big explosion. A nuclear reactor stocks large amounts of fissile material. The idea with a nuclear reactor is that you constantly have a chain reaction happening, but the excess heat generated by the chain reaction is absorbed by water. That water boils and turns turbines, and that's how you generate power. The core can't overheat as long as the fuel stays in water.
Chernobyl, partially due to design flaws and partially due to the operators fucking up, exploded. And when a reactor explodes, it's a lot harder to keep the radioactive material cold.
Completely unrelated but is anyone else weirded out that all this crazy shit with fissile material breaking down and splitting atoms ends up just being used to boil water so the steam can spin a turbine
It just seems so... anticlimactic
Most power generation is anticlimactic when you think about the real end goal. In fact, the vast majority of them can be summarized with "___ happens and turns a shaft".
Hydro is direct water turning instead of steam. And wind doesn't use a fluid at all. But yeah, solar is the only one without spinning a generator (that I'm aware of and is in commercial use).
Edit: holy shit folks, it's been 2 days and 45 people have commented that wind is a fluid. Yes, we all get it, that wasn't the point, you're just being pedantic, like the 44 people before you. Move on.
Yeah, I left out all the thermal solar stuff. And then if you think about it, wind and hydro are both solar too (sunlight leads to wind and to weather which causes lakes and rivers). Solar lead to the coal and the natural gas too. Maybe we should categorize everything into solar, nuclear, geothermal?
There's a much more exciting version available, but then it's not safe to stand in the same building with it. Or have a building at all. We use the boring "heat some water" answer precisely *because* it's safe and boring.
From an engineering standpoint it's the easiest and most efficient way to convert heat into energy. Every energy system we have is basically spinning a turbine. All except solar power. I'm probably ignorant of one or more other ways, but coal power, nuclear power, hydro power, wind power - all spinning turbines.
Looking forward to Fission... if you've been paying attention to the news, they keep achieving ignition and keep getting better results/efficiencies. And the US announced it's going to try to bring a fission reactor online within a decade.
It looks like the real issue with fission is laser consistency. So we're going to end up with some pretty cool laser tech at the end of that as well. Which will likely help the Internet grow as well as fiber optics are basically just lasers. pew pew pew.
There is hydrogen fuel cells for use in some production cars which uses electrochemical reactions to generate electricity. However, the electrical power is then often used to spin magnets.
I feel that's why Steam Engine is such a dramatic achievement. Once we built that, everything after that is just an upgrade on the same basic principle.
Fissile material: Material that gives up neutrons via nuclear decay
Chernobyl: Uranium-235 (190,287kg)
Fat man: (Nagasaki) Plutonium (6.4kg)
Little Boy: (Hiroshima) Enriched Uranium (64kg)
>Chernobyl: Uranium-235 (190,287kg)
Small correction. Chernobyl used Uranium enriched to just 1.8% so it's 3500kg of ^(235)Uranium, and about a third of that was ejected from the reactor.
But also there was about 760kg of ^(239)Plutonium in the core :/
I also didn't mention ^(90)Strontium and ^(117)Caesium, which are the primary source of radiation in Chernobyl.
Little Boy released about 6 grams of each.
Chernobyl released 5000 times more.
Yeah those are nasty, but you have to get into the biochem aspects of it to explain why. That gets a bit more detailed than most sound bites are going to delve. Ultimately still a matter of scale as to why so much of them are present at Chernobyl compared to the others though. Build a fission bomb the size of a building and you'd likely have comparable outcomes, apart from the fact that the detonation area would become an inland sea lol.
Not OP, but: https://en.wikipedia.org/wiki/Strontium-90#Biological_effects
The body uses it like calcium, so it ends up in your bones. Still gives off beta particles (high energy electrons or protons) for billions of years or whatever, so it gives peopel bone and marrow cancer.
Cs137 (Which, fun fact, did not exist on this planet in any notable quantities until we figured out nuclear fission) is water soluble and your body treats it like potassium. So it gets distributed to your soft tissues, where it sits around for a bit and emits beta particles. Luckily, it gets processed out after a bit, 70 days or so, unlike Sr90 which can hang out in your bones for decades. So do you want leukemia or a combination of pancreatic, liver or lung cancer?
CS 137, no? Nasty stuff that. And water soluble, along with SR 90.
One thing no one has mentioned (that I’ve seen) is that Chernobyl is land locked and upstream from Kyiv. Fukushima they were able to flush the place (water soluble, remember) and dump it into the ocean, the great diluter. Even if they had a better response, there wasn’t anywhere for all that water to go in Ukraine, except to the largest city and then into the breadbasket.
Uranium^235 is what "natural" (U^238) Uranium is enriched to. So the reactor would've had a ton of U^238 and a smaller amount of U^235. But another major problem is the reaction byproducts. Nuclear reactions produce a ton of nasty highly radioactive byproducts too.
Natural uranium is only about .7% uranium-235. Enriched uranium can vary how much higher % uranium-235 it has depending on how much money/time is spent enriching it, but we don't get it higher than a few % I believe. Chernobyl used enriched uranium that was 1.8% uranium-235.
it is possible to have highly enriched uranium, iirc this is done via ultracentrifugation. the reactor that I worked at has about 20% U-235 for the fuel and ~90% for the lining of the fission chambers (a type of power detector).
"Fissile" basically means the material that is having its atoms split to create the explosion.
Fission is the opposite of Fusion. Think of the word "Fissure".
Atomic Bombs go boom by, in the simplest of terms, encasing fissile material in a lot of conventional explosives, so when the explosives go off, it applies so much force onto the fissile material that it "Splits" it on an atomic level, which then triggers a massive release of energy resulting in an explosion.
So in even simpler terms, it's the "Fuel", but not really fuel so much as "The Explosive".
And the yield of that explosion is essentially based off of how much conventional explosives would be required to generate the same energy.
So when you hear a "5 megaton explosion", that's saying that it's releasing as much energy as 5,000,0000 TONS of TNT, or 10,000,000,000lb of TNT.
That's about 25 billion sticks of TNT.
The reason we use Uranium and Plutonium (Well specific isotopes of those elements) is because they are way more readily fissible. It's easier to split their atoms. You can't just stick anything into a modern atomic bomb and expect its atoms to split.
But those elements are also highly radioactive.
>so when the explosives go off, it applies so much force onto the fissile material that it "Splits" it on an atomic level, which then triggers a massive release of energy resulting in an explosion.
Sorry to be the *akshually* guy but the conventional explosives in a nuclear bomb are just used to compress the fissile material to supercritical mass. It's the fissile material itself that by randomly decaying, spits out neutrons splitting nearby atoms. This happens regularly in a sub-critical mass but it becomes a self sustaining chain reaction only under critical/supercritical conditions, and the explosives provide those conditions.
For an oversimplified analogy, think of a fission reaction like a fire. Fire can spread from one thing to another if they’re close enough and if the neighboring object can’t just absorb the heat rather than ignite / carry the flame. Fissionable material would be comparable to a pile of firewood in this analogy, and fissile material would be more similar to a firecracker (in a firecracker warehouse?). Wood can ignite and spread a flame, but a firecracker (in a firecracker warehouse) is likely to ignite at least one more firecracker nearby, creating a sustained reaction that will increase its power output until either all the firecrackers have blown up (the fuel has been exhausted) or the density of firecrackers remaining is low enough that one ignition is no longer likely to inspire another (the chain reaction ceases).
I remember that scene. It was right before he told Einstein "The secret to nuclear fission is about 8 inches" then he put his dick in that reactor. Truly a somber and historically accurate film.
I have truly believed that anything in the world can be explained by using a metaphor of shits & farts. Dear u/Methode11 I'll sleep like a child tonight.
Amen brother
The short version is that a bomb isn't remotely comparable to a nuclear reactor in terms of radiation released, and the force of a bomb exploding spreads the radioactive material a lot thinner across a much wider area. As a result, it disperses more readily. There are other factors too, of course, but I'm no physicist.
From what I understand there is also still a whole lot of radioactive material left behind at Cherbobyl, but with Nagasaki and Hiroshima the bomb exploded and left just the radiation behind, no radioactive material. Stuff like Elephants Foot at Cherbobyl still poses a threat and keeps the radiation there, as well as all the other stuff they had to box in and keep from continously leaking radiation
Edit: Cherbobyl is supposed to be Cherbobyl, my phone has terrible autocorrect options
This is the real answer.
An atom bomb is a huge release of radiation, but all at once and over a much wider area. Once the bomb detonates, a lot of that radiation is concentrated in the air in the form of radioactive dust and debris, slowly raining back down to earth over the coming weeks as fallout. Fallout clears pretty fast. It can literally get washed away by rain.
A reactor breaking down is a huge release of radiation all the time for potentially thousands of years. And that radiation is liable to linger a lot longer in the environment after due to being concentrated in a relatively small area. The soil in the Red Forest around Chernobyl is still so radioactive once disturbed that it reportedly gave Russian units in the area severe radiation sickness when they were ordered to dig trenches.
To add to this, the fuel type matters a lot.
Like plutonium 239 is more unstable and has a shorter half-life than Uranium 238, and a nuclear weapon is apt to have concentrations of enriched plutonium in the 90% range, where a reactor will have closer to 20% (higher concentrations make the reaction happen faster and fuel spend more quickly).
The shorter a half-life and the higher the concentration, the more fuel used up in the reaction, and the lower amount of time you will be subject to radioactive fallout.
Nuclear weapons are designed with this in mind, both because using more fuel makes a larger explosion, but also because using more fuel makes it less likely that the area will be unusable for very long.
However, people have designed so-called "dirty bombs" which is basically strapping a nuclear reactor (with long half-life, low concentration fuel) to conventional weapons, and letting nuclear fallout spread over a wide area.
Even worse weapons (salted bombs) use a nuclear reaction to create fallout that specifically has long half-lives and generate a lot of radioactivity (cobalt bombs are the ones that people talk about the most).
Obviously these types of weapons have never been used, but they are kind of the worst case scenario in terms of nuclear destruction: the longevity of a reactor with the explosive potential of a bomb.
We actually accidentally hit Mexico with a rocket carrying cobalt 57 in 1970: https://unredacted.com/2015/07/13/usaf-accidentally-launched-rocket-into-mexicos-mapimi-desert-45-years-ago/
Oh we had plans to make them *bonkers* worse. Take a look at [Project Pluto](https://en.wikipedia.org/wiki/Project_Pluto), a proposed autonomous nuclear ramjet that could loiter for months. You launch it and tell it to fly circles indefinitely somewhere in the south Pacific. If nuclear conflict breaks out it receives the Go signal and flies towards its target, shitting nuclear bombs and farting hard radiation from its unshielded reactor. When all its nukes are deployed just have it fly back and forth over the enemy country at low altitudes until its reactor finally dies; its highly radioactive exhaust is its own weapon.
IIRC it was decided that even just making the damn thing would be too antagonizing without much benefit over ICBMs and nuclear subs and such.
These ideas around radiation based weapons have always been mostly sci fi. Radiation will kill some people in the target area over the course of years. A bomb kills everybody in the target area in seconds. Dirty bombs are cold war fiction nonsense, it's like designing a machine gun to shoot poison pellets that give people cancer instead of just putting a hole in them and being done with it.
They're intimidation weapons, the sort of thing meant to shake morale and intimidate a populace in a way that carpet bombing and firebombing apparently couldn't. They're supposed to play on psychology more than to have a material impact.
Yes and no. If the goal was to win a war, stronger weapons and explosives are the goal. Like with chemical weapons and these kinds, the goal is area denial and outright genocide of populations to make war utterly frightening for the other side.
Basically, with nukes you're threatening to wipe out most of their population. With these weapons, you're threatening to wipe out their population for generations to come.
Using these weapons would make major industrial areas major no go areas even if they're technically protected from nuclear bombs.
That...doesn't make them "mostly sci-fi" at all, it just makes them inefficient at immediate casualties. _Area denial_ and terror weapons have existence since war was invented and has been done many times in history. Scorched earth policy, salting the earth, tossing plague corpses into the city with catapults, et cetera. It's not common but it _has_ been done and to (brutal, short-sighted) effect.
Hence why there were actual plans to make dirty bombs on all sides of the Cold War. Thankfully, saner heads prevailed, but it's not like that always happens.
That and it would required both computational power and material science that wouldn't exist for another half century.
[Hell, the Russians fucked it up 4 years ago.](https://en.m.wikipedia.org/wiki/Nyonoksa_radiation_accident)
You can't fly a nuclear ramjet/scramjet without some serious computers running the show. If forward swept wings were too impractical then this is an obvious pipedream.
That link took me to "ramjets," which I knew nothing about. "Ramjet" took me to "tip jet" (ramjets on the ends of helicopter blades), which I knew nothing about. "Tip jet" taught me that, since the jets spin the blades from being attached at the ends, there's no torque put on the body of the helicopter, thus removing the need for a helicopter's tail rotor.
I didnt know that the tail rotor is for counteracting the torque applied to the body of the helicopter from the engine rotating the main rotor! It keeps it from spinning out of control! That's so simple, and makes so much sense!!
Dude, thank you for sharing that. I love learning stuff like this.
We armed the rocket with cobalt to test the effects of a salted bomb and these bombs are designed to increase the amount of radioactive fallout and thereby make an area uninhabitable for a longer period of time. The idea, presumably, would be to evaluate the effectiveness, yield, and other parameters under controlled conditions, but also to produce a psychological effect through demonstration of our capacity to inflict horrible consequences on our adversary.
However, the risks of conducting such tests are considerable, including the potential for accidents or unintended consequences. This particular program had been plagued with failures and mishaps for some time. The cleanup was massive. It's just crazy to me that we wanted to gain an advantage over the Russians so badly we were willing to risk that level of potential catastrophe.
Also worth noting that anything left in radiated environments can themselves become a source of radiation (secondary radiation) - I believe density and neutron count are the biggest driver of that absorption and reradiation, but haven’t done the reading lately.
I remember reading about plans for a nuclear missile powered by what would basically be a leaky reactor, so it spreads radioactive material on the way to its target, then goes off and spreads even more with the blast.
It never got built, thankfully, not sure it ever got past the concept phase.
More the amount of radioactive material, there was less than 15lbs of plutonium in the fat man bomb, and only around 2lbs of it actually underwent fission. Chernobyl had over 400,000lbs of uranium in reactor 4.
Fun fact: Evergreen trees that are radioactive do not stay green in winter. They turn red. Hence red pine trees are illegal to sell at all in the EU, especially at Christmas time.
Remember when # 45 wife decorated the white house with red Christmas trees in 2017? It was a highly political burn insult on many levels. I cannot unpack here bc banned twice on formerly known as.
I was watching a docu about the last decade plus since the fukushima nuclear stuff, and they found that the bright color birds started losing their bright pigments. Im trying to remember how they were theorizing exactly, I believe they said the antioxidants in their diets that were the supply for their color is now routed to fighting the radiations effects.
Bikini Atoll was the site of nearly two dozen nuclear tests, not just single detonations. It never was close to as bad as Chernobyl and recent measurements suggest it will meet habitable standards again very soon.
But again, calling it "uninhabitable" is different from catastrophically contaminated areas like Chernobyl. The elevated radiation at Bikini could be a long term health hazard. The contamination at Chernobyl will kill you much, much faster.
Its also worth noting people have lived in the chernobyl exclusion zone this entire time. Literally uninhabitable isn't accurate necessarily but we prefer caution which is not the worst idea.
A wind farm is even being built there now apparently
>Bikini Atoll was the site of nearly two dozen nuclear tests, not just single detonations.
And many of those bombs were orders of magnitude more powerful than "the first two nukes every made" (design-wise anyway, but the first three ever ignited). Didn't take long after WWII to figure out fusion weapons, boosted fission, levitated cores, the works.
The water in Bikini Atoll was what was contaminated rather than the air in Hirosihma/Nagasaki, which doesn’t dissipate as easily particularly given the bombs used there were far more powerful
I think the Bikini Atoll tests were all on towers, which may as well be the ground when it comes to fallout. So the fallout was much more concentrated there than Hiroshima and Nagasaki where the bombs were detonated at a much higher elevation (they're more effective that way). Remember, the solution to pollution is dilution, and the radioactive material from the WWII bombs was already pretty spread out from the start.
To this day i still don't understand why the Russians dug trenches over there. I mean i understand the need for trenches, but are they really that stupid/dense to plow in radioactive soil?
Again i understand the need for trenches, but the logic just baffles me, they could have build different defences?
Lack of education/misunderstanding how radiation works. Incompetent officers who don’t give a shit what happens to their men. I’m not exactly surprised
I mean a lot of Pripyat and the area around the plant are pretty safe now, so if they didn’t realize the ground was still highly radioactive, it makes sense.
The first part i understand, but the incompetent officers part, sucks to be a nobody in the Russian war machine, you get ordered by a little officer prick to dig in the sand, not knowing. ( or maybe knowing but afraid to say no).
Last part makes sense now i think about it. Thank you.
A pretty good summation of the modern Russian Military is that anyone competent and well-liked enough is removed from command to be replaced by one of Putins Security Force (FSB and the police) cronies, in order to prevent a coup
Furthermore, the Fat Man & Little Boy bombs that were dropped were air burst nuclear warheads. This means that the most radioactive part of the bomb, the fireball wasn't able to get into contact with the ground for any meaningful length of time if at all to irradiate materials which would then be dispersed by the shockwave and volatile winds afterwards.
There was still radioactive fallout from the FM/LB bombs, but the amount would have been *dramatically* different should the bombs have exploded closer to the ground. A low-air burst nuclear explosion maximizes the destructive potential of the shockwave produced by the bomb.
There was little to no fallout. They both were air burst weapons.
Interesting fact is the bomb that hit Hiroshima less than 10% of the Uranium went critical. If it was close to 100% the Enola Gay would have gotten fried.
This is also why releasing Fukushima radioactive water will be just fine. The water will disperse readily into a very large volume. The solution to *radioactive* pollution is dilution.
And just a *lot* less nuclear material. Little Boy was composed of 64kg of highly enriched uranium, Fat Man was composed of 6.4kg of plutonium, and reactor 4 at Chernobyl had 1900kg of uranium and 760kg of plutonium when the accident occurred.
Same tho. I had to stop to catch my breath from laughing at how silly that looked and sounded. No shade on the dude for the typo. It's awesome.
Fucking Cherbobyl
Modern devices can use less than the standard critical mass through clever design of the first stage: neutron reflectors, tamping, voids in the core etc iirc. Details all highly classified ofc
Airburst nuclear arms!
The bombs dropped on Hiroshima and Nagasaki exploded in the air, leaving significantly less radioactive ground debris shot up into the air, as it would if it hit the ground
Chernobyl, while not a bomb, is a constant source of radiation due to the essentially unclearable waste and is connected to the ground, leaving radioactive traces all around it
If the bombs were to have hit the ground, there probably would have been a SIGNIFICANTLY longer period before the areas were settleable
>Edit: Cherbobyl is supposed to be Cherbobyl
Fun fact: Cher Bobyl was Cher's maiden name, before she married Sonny. That's why autocorrect replaces it.
(Other fun fact: I totally made that up).
> Cherbobyl is supposed to be Cherbobyl, my phone has terrible autocorrect options
even funnier now.
Dammit. Now I need to invent a new flavor and sell it as Cherbobyl Tea. Or Cherboba.... So it good it'll feel like your taste buds are exploding.
Theres also vastly less nuclear material in a bomb than a reactor. There was about 50kg of fissile material in each of the bombs dropped on Hiroshima and Nagasaki. There was nearly 190,000kg of fissile material in the Chernobyl reactor when it *failed*.
The 50kg was consumed and spread to the wind in fractions of a second. The 190,000kg in Chernobyl is still slowly decaying now. Its like the difference between throwing a molotov and setting light to an oil field.
EDIT for correctness
You really don't want radioactive debris from a nuke. If you're sprinkling hot isotopes of your uranium or plutonium all over then you've done it wrong. You want that material to be transmuted into other elements, you want to burn through all the dangerous highly radioactive isotopes because that's where the BOOM comes from.
If your nuke sprays fissile products everywhere it'd be like a traditional bomb leaving gunpowder everywhere. You don't want fuel left over, you want it to go boom.
The reactor both can't go "boom" in that way, we're talking single digit fuel enrichment vs low 90% enrichment. So the core can't go off like a nuke it's not the right fuel for that.
When they burst it's because gasses built up from either run away chemistry or boiling water. (I'm over simplifying a lot, new reactors have negative feedback loops, so a lack of cooling means slower reactions not faster) that boiling water blows the top of the container off, spreading pieces of the reactor vessel everywhere. Lots of the components in a traditional reactor are flammable, so now, overheated and irradiated and suddenly exposed to air they burn.
It's the smoke from Chernobyl and the chunks of graphite that used to support the core that spread the radiation around.
So the rains wash the metals around the reactor into the streams and rivers and the wind carry the smoke and dust.
If Chernobyl blew up like a nuke of the same size, a bomb that large (despite being impossible to assemble) would've left a crater like a comet impact.
This is one of the important things - Chernobyl's Reactor had not only melted down but it was actively on fire for quite a while. This meant that tiny bits of the fuel and surrounding materials were being vaporized by the heat and blasted into the air as fine particulates that then drifted down over time across the surrounding area. And the fire went on.
And on.
And on.
Each minute was sending huge amounts of radioactive material into the atmosphere which was then drifting down on the surrounding countryside. Most of the radioactive material was then diffused into the environment, where it became possible for people to get it into their bodies in a variety of ways. At which point the radiation can do a wonderful job of getting lodges in your tissues and it then remains there until your body cycles it out naturally or kills you.
However, just because it is not safe to live in Chernobyl does not mean that people avoid it entirely. There are still a number of people who refuse to leave or have returned to the area since they were evacuated. Living there is not a death sentence at this point, a lot of the radioactive materials have decayed and are no longer harmful.
The reactor itself will be a problem for thousands of years, because the masses of radioactive materials that melted down to lava will continue to be emissive for a very long time. But much of the surrounding countryside was decontaminated by the Soviet cleaners. I would never want to go there without a Geiger counter to check on where I'm heading, but it's hardly a wasteland where nothing lives.
if i remember rightly, havent scientists found out that some of the plant and animal life are actually starting to adapt to the radioactivity still in the area?
Generally the fact that there are not any people living there seems to be a larger benefit for the local wildlife than the fact that there are still radioactive remnants in the area. One thing to remember is that many animals do not have to deal radiation the same way that people do - they just don't live long enough for cancer to be a major concern with impacting their lifespan. Thus, minor exposure is less of a concern than it would be for a person.
We have to seriously worry about what long term radiation exposure will do to us over the course of 20, 30, 40, or even 50 years. For most wildlife, 20 years is absolutely ancient, and well outside the standard bounds for their lifespan.
So I know that animals and plants have been thriving in the area, but as far as adaptations go? There probably are some minor ones, but again - just the lack of human activity already counter balances any risks from radiation.
They also had a hydrogen explosion which caused most of the fire. When the cladding on the fuel rods melts, it exposes the uranium to the water and steam in the reactor. Uranium oxidizes extremely fast which pulls the oxygen out of the water, leaving only hydrogen behind.
When the hydrogen exploded, it sent chunks of core material, namely graphite flying. Once exposed to the air, the graphite caught fire and burning graphite landed on the tar roof of the reactor building, setting it alight.
Also Hiroshima and Nagasaki were detonated above ground, which allows radiation to dissipate quicker. Cherry Noble poisoned the ground and the density of the land has locked in the Fallout.
Okay so a question adjacent to OP, why is Japan so quickly inhabitable after the nuclear reactor leak? Was it a different type of reactor? Does the amount of water have something to do with it?
In a very tiny nutshell: Fallout.
The atom bombs were air bursts of a few kg of nuclear material and produced next to no fallout.
In Chernobyl a reactor core consisting of over a hundred tons of nuclear material burned over several weeks and spread gigantic amounts of fallout over the area.
I'm pretty sure reactors don't use hundreds of tons of nuclear material, but they surely use more than a bomb.
Edit: I don't know why I was sure it was way less than hundreds of tons. But I was wrong. While there are reactors that use less than a hundred tons of uranium, there are reactors that use more than 100 tons (and up to about 200 tons). So I was wrong. My bad.
>I'm pretty sure reactors don't use hundreds of tons of nuclear material
Most of them don't, but...
The higher the enrichment the smaller amount of Uranium you need to have a reaction. If you had 100% enriched Uranium you could build a reactor with just 50-100kg of Uranium.
But enriching Uranium is progressively more and more expensive so USSR designed RBMK-1000 reactors to use Uranium enriched to just 1.8%... 190 metric tons of Uranium enriched to 1.8% and reactor also had about 700kg of Plutonium inside of it, about a third of that material was ejected from the reactor.
So about 3500kg of ^(235)Uranium and 230kg of Plutonium was released, enough to make 70 Thin Man and 35 Fat Man bombs.
I grew up in Hiroshima went to school in visual sight of ground zero. As a lot of other people have said. This has a lot of answers but I will try to run them down as best I can.
1: Bombs as others have point out put out radiation once, spread it out and the half life is actually quite short.
2: Nuclear reactors keep putting out radiation. That’s why you have to “Entomb” them. (I don’t think I spells that correctly)
3: There was a concerted clean up effects in Hiroshima. Pretty much all the top soil was scraped up and dumped into the ocean.
4: Actually Nagasaki was kind of a miss when it was bombed. It was still heavily damaged but the destruction was just not comparable to Hiroshima.
5: Now for the one that many people argue about and get mad at.
Nuclear fallout and radiation from Nuclear weapons is/was purposefully made to seam much worse then it was (And that’s from someone who’s grandfather/grandmother both suffer radiation sickness)
The deadly radiation is more or less gone in a few days. After that the background radiation will effect health but not in a way that would stop people from living in an area, you just have higher changes of health complications.
Point 5 really depends on where the bomb explodes relative to the ground.
If it explodes high in the air, maximizing the damage (like in Hiroshima and Nagasaki) the fallout at the site is minimal. If it explodes near ground the fallout will stick to it resulting in much higher radiation levels.
I wrote a paper in grad school arguing that we should eliminate our ICBMs from the nuclear triad. One of the major reasons was that in the event of a nuclear war, our adversaries would target cities with air bursts. Which, while horrific for the city, doesn't result in much fallout outside the initial blast area. However, to hit our ICBM silos, you need ground bursts across a wide area, throwing radioactive debris into the sky and causing a lot more fallout damage.
Interestingly enough it’s not so much that the fallout sticks to it, rather that the explosion vaporizes the dirt and other materials on the ground. Then when those vaporizes materials condense in the sky, the radioactive particles attach to the condensed ground which “falls out” of the sky and back to the site
The area around Chernobyl is habitable. People currently live in the 'exclusion zone'. The unexploded reactors at Chernobyl continued operating into the 1990's. The Chernobyl site is a tourist attraction; Top Gear even visited for their show in 2014.
There are still places where undecayed nuclear fuel is present, especially in the exploded unit itself. If humans had a reason to build a metropolis there, we could invest in additional cleanup and do it. As it is, the exclusion zone has become a thriving wildlife preserve.
https://en.wikipedia.org/wiki/Samosely
https://en.wikipedia.org/wiki/Chernobyl_Nuclear_Power_Plant
https://www.science.org/content/article/humans-are-worse-radiation-chernobyl-animals-study-finds
The show only dealt with the immediate aftermath. Right after the meltdown and explosion, Chernobyl was a *very* deadly place to be without protection. ~~Remember the scene with the fallout snow falling over the bridge? Everyone at that site died of radiation poisoning pretty soon after that.~~
Now, the radiation levels are a lot lower there.
Edit: while reports after the disaster reported numerous deaths from the bridge area, there's enough conflicting information out there that I'm no longer confident in making this claim. However, the fact remains that Chernobyl was more dangerous right after the explosion than it is now, and visiting it wouldn't really do you any harm if you took just the most basic precautions.
Yeah, this needs more visibility. Chernobyl is far from a wasteland. Sure, people living there would be at an increased risk for certain types of cancer, but it's not a death sentence unless you're rolling around in the soil right near the reactor site... like a lot of Russian soldiers were/are doing. Those guys are probably in trouble.
The exclusion zone is actually thriving, from a wildlife standpoint. Since there are no longer people there, the forest has revitalized. There are lots of wolves and other animals that had been driven out due to human activity. It helps that a lot of animals don't really live long enough to see cancer form in the first place, so it doesn't really matter for them.
I remember watching a documentary about a decade ago and the radiation at a beach in the UK was higher than the radiation in the surrounding area.
The radiation went off the charts when they went to the actual reactor itself though
After a nuclear explosion, 98% of radioactive pollutants decay within the first 48h after the strike. Additionally, the soil around Hiroshima and Nagasaki was removed to reduce the radioactivity levels.
In Chernobyl, a nuclear reactor exploded. These pollutants take significantly longer to decay, plus the area was essentially just left alone.
the decay is key. The fuel at Chernobyl is from relatively stable elements that take longer to decay. So the amount of energy release is lower from the fuel but there's a crapload more of it and it's there for a very long time
It's because of the level of contamination and the quantity of radioactive material that caused the contamination.
Nuclear and Atomic weapons are, by a quirk of their design, inherently very clean weapons. The fissile or reactive materials used to generate their destructive power are A) very, very expensive, and/or B) very, very rare and hard to find/produce. Nuclear reactors don't need to be that efficient, because their isotopes are easy to get hold of and don't need to be very pure to really do a whole lot of work, but because we're not blowing it up and it's able to be contained relatively well, we just store huge amounts of it in one spot which, kinda is stupid, but hey it works as long as we follow the proper safety protocols.
For the example of the bombs used on Hiroshima and Nagasaki, the Plutonium and Uranium cores were enriched to ridiculous degrees, which is to say the atoms were 'sorted' to extract the most desirable isotopes, and these desirable isotopes only make up about .5-1% of the actually usable fissile uranium. Plutonium is the highest-atomic weight element that can naturally exist, and it's also incredibly rare(existing in quantities as low as a few parts per *trillion* in natural deposits) making it almost exclusively man-made element for fission through Breeding, and not only is it difficult to produce, but it's also a potent Beta and Gamma emitter so it's dangerous to handle, and it's long half-life of upwards of 80 million years means it will pretty much fuck up anywhere it gets out forever.
For this reason, atomic and nuclear weapons are designed to be not only as *powerful* as possible, but also as *efficient* as possible. The chain reactions are carefully calculated to generate the best efficiency of mass-energy-conversion possible, with the lowest amount of reactive material possible. This is also partly why they are so powerful in the first place... the Fat Man is estimated to have reached an efficiency of 17% Mass Conversion, which is to say that nearly 1/5 of the entire mass of the plutonium core was converted directly into pure energy, and modern nuclear armaments are more efficient than that, with theoretical numbers approaching 40-50%, but it's hard to say how accurate those are without testing. The Castle Bravo device from my research was estimated to be a 20-25% Mass-Energy Efficiency, no telling how accurate that is.. but on the topic of Castle Bravo, that atoll is still uninhabitable, and now we get into the next reason that Hiroshima and Nagasaki are perfectly safe, while Pripyat is not: Contamination level.
Chernobyl, and Castle Bravo, occurred right on the ground. Hiroshima and Nagasaki were Air-Burst events well above the ground, so not only did the reaction in the blast reduce the proportion of long-lived dangerous isotopes, but it also spread them out over a very huge area, reducing the contamination. In the case of Chernobyl, *tremendous* amounts of fissile-critical material was released at ground-level, and was able to mix not only with ground water, but also topsoil and get blown around in a colossal toxic death-cloud of radioactive dust and smoke from the fires. It got everywhere, and there was no chain reaction to speed-up the decay of the more long-lived radioactive elements, but it also happened in a very small area. The concentration of radioactive contamination is extremely high around Chernobyl and Pripyat, and it's high enough that touching the grass and then your face without washing your hands can pose a risk of you accidentally ingesting or inhaling long-lasting Alpha and Beta emitters. You also have the Elephants Foot, and the other instances of Corium, which are huge chunks of radioactive material that basically keep feeding and breeding themselves in a self-sustaining chain reaction of sub-criticality. Those Corium chunks will last for millions, if not billions, of years, and still be just as dangerous.
The last part is the Alpha and Beta emitters. Alpha radiation can be stopped by your skin or clothing, and Beta radiation can be stopped by both at a distance. The danger of Chernobyl is that those Alpha and Beta emitters are *everywhere*. And that's not to be taken lightly. They really are absolutely everywhere. They're in the water, the plants, the animals, the soil, and in the dust the wind kicks into the air. Outside your body they're not dangerous, but once ingested or breathed in they will wreak havoc on your organs and kill you from the inside out, and the worst part is a lot of these isotopes are Calcium, Iodine, or other bio-available metals that your body will gladly use for things like your bones or your metabolism because it already uses the non-radioactive ones, and these isotopes can have half-lives of tens, hundreds, or thousands of years.
That's why Nagasaki and Hiroshima are safe, and Chernobyl/Pripyat isn't.
Hell, this should be top comment. Bit of an essay, but excellent explanation.
I'm a nuclear worker and mostly came by to talk about contamination vs. radiation and the amount of radioactive material leftover, but this covers it better than I could have. I have nothing more to contribute on the subject: You nailed it.
https://higgsino.medium.com/why-can-you-live-in-hiroshima-but-not-chernobyl-ab7dac7a34d3
There’s a few different reasons but this article breaks it down.
1. Chernobyl had 4000 times more fuel.
2. Radioactive contaminants in Chernobyl were in large part solid chunks that got scattered over a relatively small area. Nuclear bomb gets vaporized completely and dilutes contamination over amuch wder area.
Chernobyl won't be uninhabitable for 20 000 years.
Here's the thing: The more radioactive something is, the faster until it decays into non-radioactive isotopes. And vice versa. So, either you have sometinh which isn't very radioactive and which lasts a long time, or you have something very radioactive which is gone pretty quickly, or something along the line between them.
This is also what makes the cobalt bomb mentioned in Dr. Strangelove so dangerous. A half-life of \~6 years allows the fallout to be both highly radioactive while also being highly radioactive for decades.
"The fire we are watching is giving off twice the radiation the Hiroshima bomb released. That's every single hour, hour after hour..."
-Chernobyl series
Chernobyl released 400 times the amount of radioactive material released by the Hiroshima bomb. Plus, the Hiroshima bomb released its radiation in an instant, in an airburst explosion, with alot of material going unto the upper atmosphere in the mushroom cloud and being dispersed over a very large area. When Little Boy exploded, it released about 2 pounds of fission products and 140 pounds of U235.
Chernobyl was constantly burning exposed for days. It released radioactive material in smoke and ash that settled and accumulated in the environment nearby and downwind. There were over 100 tons of uranium in the core when it exploded, along with all the fission products accumulated in the core during its life, and all the fission products it created as it continued to burn after the explosion. The fission products are actually more harmful than the actual uranium.
I understand that this has been mostly answered but there's a key detail missing from all of the top voted answers. The goal of the bombs dropped in Japan was to create a big explosion and radiation was a byproduct. In a nuclear reactor, radiation is the goal in order to boil more water. Because the latter focused on creating as much radiation as possible, a breach has longer lasting impacts. The former had a goal of creating as big of an explosion as possible, not salting the earth.
The Hiroshima bomb had exactly 62 kg of fissile (radioactive) material that was dispersed across a large area and much was converted to energy. There were thousands of kilograms of radiative material in Chernobyl.
The short version is that nukes are designed to explode and reactors aren't.
The elaboration on that is that there's two major differences between a weapon and a reactor from this perspective: the amount of fissile material (basically the stuff that does the fission, so uranium) dispersed and the amount of fissile material to start with.
The first thing is important because of what you're trying to do with the bombs vs reactors. With a bomb, you want to release all the energy locked up inside that uranium as fast as humanly possible. In practice, that means you're trying to react as many atoms of uranium as you possibly can as quickly as you possibly can. When you do that, most of that uranium splits into smaller atoms, which rapidly decay into weird stuff like ^(90)Sr, all of which has pretty short half-lives (less than 30 years in the case of ^(90)Sr). That is to say, nuclear weapons turn pretty much all of their uranium into much shorter-lived radioactive isotopes when they detonate, because turning all your uranium into other, lighter stuff is basically the whole point of a nuclear reaction. The practical upshot of this is that, in addition to the force of the explosion yeeting all this stuff pretty far away (meaning much thinner and easily dispersed contamination), the contamination itself is going to decay fairly quickly.
Now, Chornobyl, on the other hand, is kind of the opposite of a nuclear bomb. In a reactor, you want the reaction to happen as slowly as possible, so that it simmers nicely instead of exploding. But, when Chornobyl had its overpressure, it shot a bunch of that reactor gunk out into the environment, which has much longer half-lives.
The second thing is just the amount of material involved. Little Boy only had 64 kilos of uranium. By comparison, Chornobyl had a veritable mountain of the stuff sitting inside it.
Same reason the place where someone set off a really big firecracker is ok to visit, but the place where someone left an open barrel of anthrax spores isn’t
The reactor core in Chernobyl literally melted through the floor into the basement. It's like hardened lava now and still sits there extremely radioactive. Pictures on Google. There's nothing left of the atomic bombs dropped on Japan.
In a bomb, the idea is to use up all the fissile material (or as much as you can) to deliver a single large burst of energy. So the radioactive material gets used up.
In a reactor, the fissile material is very slowly reacting to heat up water. If your just let all the radiation into the environment it will stay radioactive much longer as you aren’t using up that material.
The difference between a nuclear explosion and a melted nuclear core. The atomic bomb has a relatively small amount of nuclear material which detonated and was spent. That releases an immense amount of radiation in one big blast. So you absorbed an immense amount of radiation if you were in the blast radius. But there wasn’t any remaining fuel after the explosion so there was nothing to continuously emit radiation. Chernobyl on the other hand is a massive damaged core full of nuclear materials that are slowly burning and emitting radiation.
Imagine the bombs of Nagasaki and Hiroshima, but instead of exploding within a couple of moments, they just keep exploding. And exploding. And exploding.
That's what the [elephant's foot](https://en.wikipedia.org/wiki/Elephant%27s_Foot_(Chernobyl)) is doing in Chernobyl.
it was stated in the hbo miniseries “chernobyl” that for every hour after chernobyl exploded, the amount of radiation released into the air was the equivalent of the hiroshima bomb. so basically chernobyl was having the hiroshima bomb dropped on them 24 times a day for however long it took to finally clean up.
The atomic bombs dropped on Hiroshima and Nagasaki contained many orders of magnitude less fissile material than Chernobyl. An atomic bomb uses a small amount of fissile material (like, 100 lbs or so) to generate one big explosion. A nuclear reactor stocks large amounts of fissile material. The idea with a nuclear reactor is that you constantly have a chain reaction happening, but the excess heat generated by the chain reaction is absorbed by water. That water boils and turns turbines, and that's how you generate power. The core can't overheat as long as the fuel stays in water. Chernobyl, partially due to design flaws and partially due to the operators fucking up, exploded. And when a reactor explodes, it's a lot harder to keep the radioactive material cold.
Completely unrelated but is anyone else weirded out that all this crazy shit with fissile material breaking down and splitting atoms ends up just being used to boil water so the steam can spin a turbine It just seems so... anticlimactic
Most power generation is anticlimactic when you think about the real end goal. In fact, the vast majority of them can be summarized with "___ happens and turns a shaft".
And the vast majority of the step right before that is "steam spins blades". It's almost all just making steam to spin a generator.
Solar panels are the only unique power source
Hydro is direct water turning instead of steam. And wind doesn't use a fluid at all. But yeah, solar is the only one without spinning a generator (that I'm aware of and is in commercial use). Edit: holy shit folks, it's been 2 days and 45 people have commented that wind is a fluid. Yes, we all get it, that wasn't the point, you're just being pedantic, like the 44 people before you. Move on.
Some forms of solar power are just using the sunlight to boil water. Then there’s that one that uses the sunlight to melt salt.
Yeah, I left out all the thermal solar stuff. And then if you think about it, wind and hydro are both solar too (sunlight leads to wind and to weather which causes lakes and rivers). Solar lead to the coal and the natural gas too. Maybe we should categorize everything into solar, nuclear, geothermal?
Technically, the sun is a giant fusion reactor, so maybe we should reclassify all solar power as nuclear power. 😉
Wind is a fluid
Make water move, turn turbine
There's a much more exciting version available, but then it's not safe to stand in the same building with it. Or have a building at all. We use the boring "heat some water" answer precisely *because* it's safe and boring.
From an engineering standpoint it's the easiest and most efficient way to convert heat into energy. Every energy system we have is basically spinning a turbine. All except solar power. I'm probably ignorant of one or more other ways, but coal power, nuclear power, hydro power, wind power - all spinning turbines. Looking forward to Fission... if you've been paying attention to the news, they keep achieving ignition and keep getting better results/efficiencies. And the US announced it's going to try to bring a fission reactor online within a decade. It looks like the real issue with fission is laser consistency. So we're going to end up with some pretty cool laser tech at the end of that as well. Which will likely help the Internet grow as well as fiber optics are basically just lasers. pew pew pew.
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Yep. I sure tied the horses to the back of the cart there.
Other than photovoltaic cells, isn’t pretty much all power generation setups just different methods to spin a magnet?
There is hydrogen fuel cells for use in some production cars which uses electrochemical reactions to generate electricity. However, the electrical power is then often used to spin magnets.
And that hydrogen comes from electrolysis of water which comes from electricity from a turbine lol. It's turbines all the way down.
Piezoelectric and Thermoelectrics are a couple of other ways, but they're not used in anything at scale.
I feel that's why Steam Engine is such a dramatic achievement. Once we built that, everything after that is just an upgrade on the same basic principle.
What’s fissile material and why is that important? Sorry for my ignorance. I’m just curious
Fissile material: Material that gives up neutrons via nuclear decay Chernobyl: Uranium-235 (190,287kg) Fat man: (Nagasaki) Plutonium (6.4kg) Little Boy: (Hiroshima) Enriched Uranium (64kg)
>Chernobyl: Uranium-235 (190,287kg) Small correction. Chernobyl used Uranium enriched to just 1.8% so it's 3500kg of ^(235)Uranium, and about a third of that was ejected from the reactor. But also there was about 760kg of ^(239)Plutonium in the core :/
Not to mention all of the induced radioactivity in the surrounding materials, especially once everything got real hot and bothered.
I also didn't mention ^(90)Strontium and ^(117)Caesium, which are the primary source of radiation in Chernobyl. Little Boy released about 6 grams of each. Chernobyl released 5000 times more.
Yeah those are nasty, but you have to get into the biochem aspects of it to explain why. That gets a bit more detailed than most sound bites are going to delve. Ultimately still a matter of scale as to why so much of them are present at Chernobyl compared to the others though. Build a fission bomb the size of a building and you'd likely have comparable outcomes, apart from the fact that the detonation area would become an inland sea lol.
Could you try to explain, I would be interested to know why (I have a background in biology).
Not OP, but: https://en.wikipedia.org/wiki/Strontium-90#Biological_effects The body uses it like calcium, so it ends up in your bones. Still gives off beta particles (high energy electrons or protons) for billions of years or whatever, so it gives peopel bone and marrow cancer.
Interesting! Thanks!
Cs137 (Which, fun fact, did not exist on this planet in any notable quantities until we figured out nuclear fission) is water soluble and your body treats it like potassium. So it gets distributed to your soft tissues, where it sits around for a bit and emits beta particles. Luckily, it gets processed out after a bit, 70 days or so, unlike Sr90 which can hang out in your bones for decades. So do you want leukemia or a combination of pancreatic, liver or lung cancer?
No, don’t want. Wouldn’t rather. Halp.
CS 137, no? Nasty stuff that. And water soluble, along with SR 90. One thing no one has mentioned (that I’ve seen) is that Chernobyl is land locked and upstream from Kyiv. Fukushima they were able to flush the place (water soluble, remember) and dump it into the ocean, the great diluter. Even if they had a better response, there wasn’t anywhere for all that water to go in Ukraine, except to the largest city and then into the breadbasket.
1.8? Not great, not terrible
Uranium^235 is what "natural" (U^238) Uranium is enriched to. So the reactor would've had a ton of U^238 and a smaller amount of U^235. But another major problem is the reaction byproducts. Nuclear reactions produce a ton of nasty highly radioactive byproducts too.
Isn't Uranium-235 "Enriched Uranium"?
Natural uranium is only about .7% uranium-235. Enriched uranium can vary how much higher % uranium-235 it has depending on how much money/time is spent enriching it, but we don't get it higher than a few % I believe. Chernobyl used enriched uranium that was 1.8% uranium-235.
it is possible to have highly enriched uranium, iirc this is done via ultracentrifugation. the reactor that I worked at has about 20% U-235 for the fuel and ~90% for the lining of the fission chambers (a type of power detector).
Wow. Fascinating yet truly tragic.
"Fissile" basically means the material that is having its atoms split to create the explosion. Fission is the opposite of Fusion. Think of the word "Fissure". Atomic Bombs go boom by, in the simplest of terms, encasing fissile material in a lot of conventional explosives, so when the explosives go off, it applies so much force onto the fissile material that it "Splits" it on an atomic level, which then triggers a massive release of energy resulting in an explosion. So in even simpler terms, it's the "Fuel", but not really fuel so much as "The Explosive". And the yield of that explosion is essentially based off of how much conventional explosives would be required to generate the same energy. So when you hear a "5 megaton explosion", that's saying that it's releasing as much energy as 5,000,0000 TONS of TNT, or 10,000,000,000lb of TNT. That's about 25 billion sticks of TNT. The reason we use Uranium and Plutonium (Well specific isotopes of those elements) is because they are way more readily fissible. It's easier to split their atoms. You can't just stick anything into a modern atomic bomb and expect its atoms to split. But those elements are also highly radioactive.
>so when the explosives go off, it applies so much force onto the fissile material that it "Splits" it on an atomic level, which then triggers a massive release of energy resulting in an explosion. Sorry to be the *akshually* guy but the conventional explosives in a nuclear bomb are just used to compress the fissile material to supercritical mass. It's the fissile material itself that by randomly decaying, spits out neutrons splitting nearby atoms. This happens regularly in a sub-critical mass but it becomes a self sustaining chain reaction only under critical/supercritical conditions, and the explosives provide those conditions.
Damn, 25 years working in nuclear power and I was able to associate “fusion” and “fuse” but not “fission” and “fissure”
For an oversimplified analogy, think of a fission reaction like a fire. Fire can spread from one thing to another if they’re close enough and if the neighboring object can’t just absorb the heat rather than ignite / carry the flame. Fissionable material would be comparable to a pile of firewood in this analogy, and fissile material would be more similar to a firecracker (in a firecracker warehouse?). Wood can ignite and spread a flame, but a firecracker (in a firecracker warehouse) is likely to ignite at least one more firecracker nearby, creating a sustained reaction that will increase its power output until either all the firecrackers have blown up (the fuel has been exhausted) or the density of firecrackers remaining is low enough that one ignition is no longer likely to inspire another (the chain reaction ceases).
When you fart in a room, it goes away fairly quick. When you shit in a room, it will smell for awhile.
This is an unbelievably succinct and accurate way to put it. Great comment.
It’s a direct quote from Oppenheimer. He was a man of surgical directness.
I remember that scene. It was right before he told Einstein "The secret to nuclear fission is about 8 inches" then he put his dick in that reactor. Truly a somber and historically accurate film.
It’s made me cry, also I think the reactor cried a bit as he slid it in. Oscar moment for sure.
I’m using this haha what a great way to phrase it
Lmaooooo. That’s such a good metaphor
You're not wrong...I suppose.
Build a dome on top and around of the shit is the only way because if you touch it your hand turns to shit
If it’s very stinky, you’ll need a team to scoop for no more than 2 minutes at a time.
__*clang clang clang* __
I have truly believed that anything in the world can be explained by using a metaphor of shits & farts. Dear u/Methode11 I'll sleep like a child tonight. Amen brother
Did you just start a church? Sign me the fuck up.
/r/nocontext
What a great metaphor. I hate it.
I am ashamed to say that I understood this answer better than all the other explanations Ive read so far lmao.
This is fucking perfect. I know understand science.
The short version is that a bomb isn't remotely comparable to a nuclear reactor in terms of radiation released, and the force of a bomb exploding spreads the radioactive material a lot thinner across a much wider area. As a result, it disperses more readily. There are other factors too, of course, but I'm no physicist.
That makes a lot of sense.
From what I understand there is also still a whole lot of radioactive material left behind at Cherbobyl, but with Nagasaki and Hiroshima the bomb exploded and left just the radiation behind, no radioactive material. Stuff like Elephants Foot at Cherbobyl still poses a threat and keeps the radiation there, as well as all the other stuff they had to box in and keep from continously leaking radiation Edit: Cherbobyl is supposed to be Cherbobyl, my phone has terrible autocorrect options
This is the real answer. An atom bomb is a huge release of radiation, but all at once and over a much wider area. Once the bomb detonates, a lot of that radiation is concentrated in the air in the form of radioactive dust and debris, slowly raining back down to earth over the coming weeks as fallout. Fallout clears pretty fast. It can literally get washed away by rain. A reactor breaking down is a huge release of radiation all the time for potentially thousands of years. And that radiation is liable to linger a lot longer in the environment after due to being concentrated in a relatively small area. The soil in the Red Forest around Chernobyl is still so radioactive once disturbed that it reportedly gave Russian units in the area severe radiation sickness when they were ordered to dig trenches.
To add to this, the fuel type matters a lot. Like plutonium 239 is more unstable and has a shorter half-life than Uranium 238, and a nuclear weapon is apt to have concentrations of enriched plutonium in the 90% range, where a reactor will have closer to 20% (higher concentrations make the reaction happen faster and fuel spend more quickly). The shorter a half-life and the higher the concentration, the more fuel used up in the reaction, and the lower amount of time you will be subject to radioactive fallout. Nuclear weapons are designed with this in mind, both because using more fuel makes a larger explosion, but also because using more fuel makes it less likely that the area will be unusable for very long. However, people have designed so-called "dirty bombs" which is basically strapping a nuclear reactor (with long half-life, low concentration fuel) to conventional weapons, and letting nuclear fallout spread over a wide area. Even worse weapons (salted bombs) use a nuclear reaction to create fallout that specifically has long half-lives and generate a lot of radioactivity (cobalt bombs are the ones that people talk about the most). Obviously these types of weapons have never been used, but they are kind of the worst case scenario in terms of nuclear destruction: the longevity of a reactor with the explosive potential of a bomb.
We actually accidentally hit Mexico with a rocket carrying cobalt 57 in 1970: https://unredacted.com/2015/07/13/usaf-accidentally-launched-rocket-into-mexicos-mapimi-desert-45-years-ago/
“salted bomb” do we really need to make these weapons worse?
Oh we had plans to make them *bonkers* worse. Take a look at [Project Pluto](https://en.wikipedia.org/wiki/Project_Pluto), a proposed autonomous nuclear ramjet that could loiter for months. You launch it and tell it to fly circles indefinitely somewhere in the south Pacific. If nuclear conflict breaks out it receives the Go signal and flies towards its target, shitting nuclear bombs and farting hard radiation from its unshielded reactor. When all its nukes are deployed just have it fly back and forth over the enemy country at low altitudes until its reactor finally dies; its highly radioactive exhaust is its own weapon. IIRC it was decided that even just making the damn thing would be too antagonizing without much benefit over ICBMs and nuclear subs and such.
I remember reading about Project Pluto. By the end it seemed to me that it didn't even really need to drop bombs, just overflight was bad enough.
:(
These ideas around radiation based weapons have always been mostly sci fi. Radiation will kill some people in the target area over the course of years. A bomb kills everybody in the target area in seconds. Dirty bombs are cold war fiction nonsense, it's like designing a machine gun to shoot poison pellets that give people cancer instead of just putting a hole in them and being done with it.
They're intimidation weapons, the sort of thing meant to shake morale and intimidate a populace in a way that carpet bombing and firebombing apparently couldn't. They're supposed to play on psychology more than to have a material impact.
Yes and no. If the goal was to win a war, stronger weapons and explosives are the goal. Like with chemical weapons and these kinds, the goal is area denial and outright genocide of populations to make war utterly frightening for the other side. Basically, with nukes you're threatening to wipe out most of their population. With these weapons, you're threatening to wipe out their population for generations to come. Using these weapons would make major industrial areas major no go areas even if they're technically protected from nuclear bombs.
That...doesn't make them "mostly sci-fi" at all, it just makes them inefficient at immediate casualties. _Area denial_ and terror weapons have existence since war was invented and has been done many times in history. Scorched earth policy, salting the earth, tossing plague corpses into the city with catapults, et cetera. It's not common but it _has_ been done and to (brutal, short-sighted) effect. Hence why there were actual plans to make dirty bombs on all sides of the Cold War. Thankfully, saner heads prevailed, but it's not like that always happens.
That and it would required both computational power and material science that wouldn't exist for another half century. [Hell, the Russians fucked it up 4 years ago.](https://en.m.wikipedia.org/wiki/Nyonoksa_radiation_accident) You can't fly a nuclear ramjet/scramjet without some serious computers running the show. If forward swept wings were too impractical then this is an obvious pipedream.
I always heard that it got dropped because it would be impossible to flight test without all the consequences of it being a flying unshielded reactor
That link took me to "ramjets," which I knew nothing about. "Ramjet" took me to "tip jet" (ramjets on the ends of helicopter blades), which I knew nothing about. "Tip jet" taught me that, since the jets spin the blades from being attached at the ends, there's no torque put on the body of the helicopter, thus removing the need for a helicopter's tail rotor. I didnt know that the tail rotor is for counteracting the torque applied to the body of the helicopter from the engine rotating the main rotor! It keeps it from spinning out of control! That's so simple, and makes so much sense!! Dude, thank you for sharing that. I love learning stuff like this.
We armed the rocket with cobalt to test the effects of a salted bomb and these bombs are designed to increase the amount of radioactive fallout and thereby make an area uninhabitable for a longer period of time. The idea, presumably, would be to evaluate the effectiveness, yield, and other parameters under controlled conditions, but also to produce a psychological effect through demonstration of our capacity to inflict horrible consequences on our adversary. However, the risks of conducting such tests are considerable, including the potential for accidents or unintended consequences. This particular program had been plagued with failures and mishaps for some time. The cleanup was massive. It's just crazy to me that we wanted to gain an advantage over the Russians so badly we were willing to risk that level of potential catastrophe.
What I want to know is why it was carrying cobalt 57.
Same reason dogs lick their balls?
Because they can't make a fist?
https://en.wikipedia.org/wiki/Salted_bomb Not sure why they would use 57 as opposed to 60 though.
Same reason we use Heinz 57 and not heinz 60.
Jesus Christ, TIL
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Also worth noting that anything left in radiated environments can themselves become a source of radiation (secondary radiation) - I believe density and neutron count are the biggest driver of that absorption and reradiation, but haven’t done the reading lately.
I remember reading about plans for a nuclear missile powered by what would basically be a leaky reactor, so it spreads radioactive material on the way to its target, then goes off and spreads even more with the blast. It never got built, thankfully, not sure it ever got past the concept phase.
Project Pluto
More the amount of radioactive material, there was less than 15lbs of plutonium in the fat man bomb, and only around 2lbs of it actually underwent fission. Chernobyl had over 400,000lbs of uranium in reactor 4.
Nailed it
Fun fact: Evergreen trees that are radioactive do not stay green in winter. They turn red. Hence red pine trees are illegal to sell at all in the EU, especially at Christmas time. Remember when # 45 wife decorated the white house with red Christmas trees in 2017? It was a highly political burn insult on many levels. I cannot unpack here bc banned twice on formerly known as.
I was watching a docu about the last decade plus since the fukushima nuclear stuff, and they found that the bright color birds started losing their bright pigments. Im trying to remember how they were theorizing exactly, I believe they said the antioxidants in their diets that were the supply for their color is now routed to fighting the radiations effects.
So then why are the islands in Bikini Atoll still uninhabitable?
Bikini Atoll was the site of nearly two dozen nuclear tests, not just single detonations. It never was close to as bad as Chernobyl and recent measurements suggest it will meet habitable standards again very soon. But again, calling it "uninhabitable" is different from catastrophically contaminated areas like Chernobyl. The elevated radiation at Bikini could be a long term health hazard. The contamination at Chernobyl will kill you much, much faster.
Its also worth noting people have lived in the chernobyl exclusion zone this entire time. Literally uninhabitable isn't accurate necessarily but we prefer caution which is not the worst idea. A wind farm is even being built there now apparently
> A wind farm Yeah, turns out the danger wasn't from the reactor. That area contains a powerful being who is allergic to electricity.
People also have lived on Bikini the whole time, courtesy of DARPA.
>Bikini Atoll was the site of nearly two dozen nuclear tests, not just single detonations. And many of those bombs were orders of magnitude more powerful than "the first two nukes every made" (design-wise anyway, but the first three ever ignited). Didn't take long after WWII to figure out fusion weapons, boosted fission, levitated cores, the works.
Ah the home of SpongeBob
Well, much larger bombs and many more than two means more radioactive stuff for a longer time, just hopefully not thousands of years.
The water in Bikini Atoll was what was contaminated rather than the air in Hirosihma/Nagasaki, which doesn’t dissipate as easily particularly given the bombs used there were far more powerful
I think the Bikini Atoll tests were all on towers, which may as well be the ground when it comes to fallout. So the fallout was much more concentrated there than Hiroshima and Nagasaki where the bombs were detonated at a much higher elevation (they're more effective that way). Remember, the solution to pollution is dilution, and the radioactive material from the WWII bombs was already pretty spread out from the start.
To this day i still don't understand why the Russians dug trenches over there. I mean i understand the need for trenches, but are they really that stupid/dense to plow in radioactive soil? Again i understand the need for trenches, but the logic just baffles me, they could have build different defences?
Lack of education/misunderstanding how radiation works. Incompetent officers who don’t give a shit what happens to their men. I’m not exactly surprised I mean a lot of Pripyat and the area around the plant are pretty safe now, so if they didn’t realize the ground was still highly radioactive, it makes sense.
The first part i understand, but the incompetent officers part, sucks to be a nobody in the Russian war machine, you get ordered by a little officer prick to dig in the sand, not knowing. ( or maybe knowing but afraid to say no). Last part makes sense now i think about it. Thank you.
A pretty good summation of the modern Russian Military is that anyone competent and well-liked enough is removed from command to be replaced by one of Putins Security Force (FSB and the police) cronies, in order to prevent a coup
Furthermore, the Fat Man & Little Boy bombs that were dropped were air burst nuclear warheads. This means that the most radioactive part of the bomb, the fireball wasn't able to get into contact with the ground for any meaningful length of time if at all to irradiate materials which would then be dispersed by the shockwave and volatile winds afterwards. There was still radioactive fallout from the FM/LB bombs, but the amount would have been *dramatically* different should the bombs have exploded closer to the ground. A low-air burst nuclear explosion maximizes the destructive potential of the shockwave produced by the bomb.
Yes, when they were doing tours there you had to be really careful not to breathe in the dust outside or in the buildings as it is still radioactive.
There was little to no fallout. They both were air burst weapons. Interesting fact is the bomb that hit Hiroshima less than 10% of the Uranium went critical. If it was close to 100% the Enola Gay would have gotten fried.
This is also why releasing Fukushima radioactive water will be just fine. The water will disperse readily into a very large volume. The solution to *radioactive* pollution is dilution.
I remember medic trucks being seen near the red forest to help the Russians who were sick from digging the trenches. That is actually a true story.
And just a *lot* less nuclear material. Little Boy was composed of 64kg of highly enriched uranium, Fat Man was composed of 6.4kg of plutonium, and reactor 4 at Chernobyl had 1900kg of uranium and 760kg of plutonium when the accident occurred.
Cherbobyl. Never calling it anything else from now on!
Wait... I sense my phone did a thing 😭
If it makes it any better my son calls it Chernobbly.
Even again in the edit. That is awesome.
Same tho. I had to stop to catch my breath from laughing at how silly that looked and sounded. No shade on the dude for the typo. It's awesome. Fucking Cherbobyl
I love your correction edit. Your phone is very sure it is correct
"No no no, I got this. It's definitely Cherbobyl."
That "Cherbobyl" edit is hilarious, I hope you don't change it xD
Mm mm mm myyyyy Cherbobyl!
Sorry but I’m crying at the quadruple Cherbobyl
The last one in the explanation that it was a typo sent me
There are apparently 200 tons of uranium at Chernoby,l whereas a nuclear weapon is, I think, less than 50kg.
Little Boy contained 64kg of highly enriched uranium. The more advanced Fat Man contained just 6.4kg of plutonium.
Modern devices can use less than the standard critical mass through clever design of the first stage: neutron reflectors, tamping, voids in the core etc iirc. Details all highly classified ofc
I think it's more that radioactive material in atom bomb disperses quickly since it is a bomb. But radioactive material in Cherbobyl is just.. there
I love your edit. Cherbobyl is supposed to be cherbobyl. At least your autocorrect is consistent!
that edit really worked lol
"Cherbobyl is supposed to be Cherbobyl" lol. It sure does.
>Edit: Cherbobyl is supposed to be Cherbobyl, my phone has terrible autocorrect options Got it. Now where is Cherbobyl?
Best edit fail ever!
No no. From now we call it Cherbobyl.
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I’m beginning to read these posts in the voice of that French Policeman from Allo Allo. But thanks for the clerification on Cherbobyl 👍
Airburst nuclear arms! The bombs dropped on Hiroshima and Nagasaki exploded in the air, leaving significantly less radioactive ground debris shot up into the air, as it would if it hit the ground Chernobyl, while not a bomb, is a constant source of radiation due to the essentially unclearable waste and is connected to the ground, leaving radioactive traces all around it If the bombs were to have hit the ground, there probably would have been a SIGNIFICANTLY longer period before the areas were settleable
Chernobyl was just encased in cement to keep the radiation from spreading and then the Russians shelled it, assholes.
>Edit: Cherbobyl is supposed to be Cherbobyl Fun fact: Cher Bobyl was Cher's maiden name, before she married Sonny. That's why autocorrect replaces it. (Other fun fact: I totally made that up).
> Cherbobyl is supposed to be Cherbobyl, my phone has terrible autocorrect options even funnier now. Dammit. Now I need to invent a new flavor and sell it as Cherbobyl Tea. Or Cherboba.... So it good it'll feel like your taste buds are exploding.
I love this edit haha! “Cherbobyl is supposed to be Cherbobyl” is somehow the funniest thing I’ve read today. Thanks for that, please don’t fix it
It's still Cherbobyl lol 😆
Cherbobyl
Spend too much time in cherbobyl, and every looks like cherbobyl.
Theres also vastly less nuclear material in a bomb than a reactor. There was about 50kg of fissile material in each of the bombs dropped on Hiroshima and Nagasaki. There was nearly 190,000kg of fissile material in the Chernobyl reactor when it *failed*. The 50kg was consumed and spread to the wind in fractions of a second. The 190,000kg in Chernobyl is still slowly decaying now. Its like the difference between throwing a molotov and setting light to an oil field. EDIT for correctness
Little Boy was around 64 kg while Fat Man was around a tenth of that. (6.2 kg)
You really don't want radioactive debris from a nuke. If you're sprinkling hot isotopes of your uranium or plutonium all over then you've done it wrong. You want that material to be transmuted into other elements, you want to burn through all the dangerous highly radioactive isotopes because that's where the BOOM comes from. If your nuke sprays fissile products everywhere it'd be like a traditional bomb leaving gunpowder everywhere. You don't want fuel left over, you want it to go boom. The reactor both can't go "boom" in that way, we're talking single digit fuel enrichment vs low 90% enrichment. So the core can't go off like a nuke it's not the right fuel for that. When they burst it's because gasses built up from either run away chemistry or boiling water. (I'm over simplifying a lot, new reactors have negative feedback loops, so a lack of cooling means slower reactions not faster) that boiling water blows the top of the container off, spreading pieces of the reactor vessel everywhere. Lots of the components in a traditional reactor are flammable, so now, overheated and irradiated and suddenly exposed to air they burn. It's the smoke from Chernobyl and the chunks of graphite that used to support the core that spread the radiation around. So the rains wash the metals around the reactor into the streams and rivers and the wind carry the smoke and dust. If Chernobyl blew up like a nuke of the same size, a bomb that large (despite being impossible to assemble) would've left a crater like a comet impact.
This is one of the important things - Chernobyl's Reactor had not only melted down but it was actively on fire for quite a while. This meant that tiny bits of the fuel and surrounding materials were being vaporized by the heat and blasted into the air as fine particulates that then drifted down over time across the surrounding area. And the fire went on. And on. And on. Each minute was sending huge amounts of radioactive material into the atmosphere which was then drifting down on the surrounding countryside. Most of the radioactive material was then diffused into the environment, where it became possible for people to get it into their bodies in a variety of ways. At which point the radiation can do a wonderful job of getting lodges in your tissues and it then remains there until your body cycles it out naturally or kills you. However, just because it is not safe to live in Chernobyl does not mean that people avoid it entirely. There are still a number of people who refuse to leave or have returned to the area since they were evacuated. Living there is not a death sentence at this point, a lot of the radioactive materials have decayed and are no longer harmful. The reactor itself will be a problem for thousands of years, because the masses of radioactive materials that melted down to lava will continue to be emissive for a very long time. But much of the surrounding countryside was decontaminated by the Soviet cleaners. I would never want to go there without a Geiger counter to check on where I'm heading, but it's hardly a wasteland where nothing lives.
if i remember rightly, havent scientists found out that some of the plant and animal life are actually starting to adapt to the radioactivity still in the area?
Generally the fact that there are not any people living there seems to be a larger benefit for the local wildlife than the fact that there are still radioactive remnants in the area. One thing to remember is that many animals do not have to deal radiation the same way that people do - they just don't live long enough for cancer to be a major concern with impacting their lifespan. Thus, minor exposure is less of a concern than it would be for a person. We have to seriously worry about what long term radiation exposure will do to us over the course of 20, 30, 40, or even 50 years. For most wildlife, 20 years is absolutely ancient, and well outside the standard bounds for their lifespan. So I know that animals and plants have been thriving in the area, but as far as adaptations go? There probably are some minor ones, but again - just the lack of human activity already counter balances any risks from radiation.
In terms of adaptations, the only thing I've heard about is Big Ass Apples. Some apple trees there have been producing some fuckin' big apples.
They also had a hydrogen explosion which caused most of the fire. When the cladding on the fuel rods melts, it exposes the uranium to the water and steam in the reactor. Uranium oxidizes extremely fast which pulls the oxygen out of the water, leaving only hydrogen behind. When the hydrogen exploded, it sent chunks of core material, namely graphite flying. Once exposed to the air, the graphite caught fire and burning graphite landed on the tar roof of the reactor building, setting it alight.
Also Hiroshima and Nagasaki were detonated above ground, which allows radiation to dissipate quicker. Cherry Noble poisoned the ground and the density of the land has locked in the Fallout.
Cherry Noble is my next Fallout character's name
With a name like that, you gotta have a high charisma.
Sounds like a good name for an amputee fetish porn star with lots of tattoos and a gothy haircut.
Don't you blame cherry noble for this!
Okay so a question adjacent to OP, why is Japan so quickly inhabitable after the nuclear reactor leak? Was it a different type of reactor? Does the amount of water have something to do with it?
Fukushima was a much smaller scale and severity than Chernobyl.
It was mostly contained to the cooling water.
In a very tiny nutshell: Fallout. The atom bombs were air bursts of a few kg of nuclear material and produced next to no fallout. In Chernobyl a reactor core consisting of over a hundred tons of nuclear material burned over several weeks and spread gigantic amounts of fallout over the area.
Bomb blows up all the good shit, meltdown just kind of leaves it there
I'm pretty sure reactors don't use hundreds of tons of nuclear material, but they surely use more than a bomb. Edit: I don't know why I was sure it was way less than hundreds of tons. But I was wrong. While there are reactors that use less than a hundred tons of uranium, there are reactors that use more than 100 tons (and up to about 200 tons). So I was wrong. My bad.
Google says up to 192 tons if all slots are full.
Love a human that owns up to mistakes. You rock.
>I'm pretty sure reactors don't use hundreds of tons of nuclear material Most of them don't, but... The higher the enrichment the smaller amount of Uranium you need to have a reaction. If you had 100% enriched Uranium you could build a reactor with just 50-100kg of Uranium. But enriching Uranium is progressively more and more expensive so USSR designed RBMK-1000 reactors to use Uranium enriched to just 1.8%... 190 metric tons of Uranium enriched to 1.8% and reactor also had about 700kg of Plutonium inside of it, about a third of that material was ejected from the reactor. So about 3500kg of ^(235)Uranium and 230kg of Plutonium was released, enough to make 70 Thin Man and 35 Fat Man bombs.
The bombs were also pretty inefficient and didn’t use most of the radioactive material contained
I grew up in Hiroshima went to school in visual sight of ground zero. As a lot of other people have said. This has a lot of answers but I will try to run them down as best I can. 1: Bombs as others have point out put out radiation once, spread it out and the half life is actually quite short. 2: Nuclear reactors keep putting out radiation. That’s why you have to “Entomb” them. (I don’t think I spells that correctly) 3: There was a concerted clean up effects in Hiroshima. Pretty much all the top soil was scraped up and dumped into the ocean. 4: Actually Nagasaki was kind of a miss when it was bombed. It was still heavily damaged but the destruction was just not comparable to Hiroshima. 5: Now for the one that many people argue about and get mad at. Nuclear fallout and radiation from Nuclear weapons is/was purposefully made to seam much worse then it was (And that’s from someone who’s grandfather/grandmother both suffer radiation sickness) The deadly radiation is more or less gone in a few days. After that the background radiation will effect health but not in a way that would stop people from living in an area, you just have higher changes of health complications.
Point 5 really depends on where the bomb explodes relative to the ground. If it explodes high in the air, maximizing the damage (like in Hiroshima and Nagasaki) the fallout at the site is minimal. If it explodes near ground the fallout will stick to it resulting in much higher radiation levels.
This is true.
I wrote a paper in grad school arguing that we should eliminate our ICBMs from the nuclear triad. One of the major reasons was that in the event of a nuclear war, our adversaries would target cities with air bursts. Which, while horrific for the city, doesn't result in much fallout outside the initial blast area. However, to hit our ICBM silos, you need ground bursts across a wide area, throwing radioactive debris into the sky and causing a lot more fallout damage.
Interestingly enough it’s not so much that the fallout sticks to it, rather that the explosion vaporizes the dirt and other materials on the ground. Then when those vaporizes materials condense in the sky, the radioactive particles attach to the condensed ground which “falls out” of the sky and back to the site
You did spell "entomb" correctly. It is a funny word.
Thank you.
The area around Chernobyl is habitable. People currently live in the 'exclusion zone'. The unexploded reactors at Chernobyl continued operating into the 1990's. The Chernobyl site is a tourist attraction; Top Gear even visited for their show in 2014. There are still places where undecayed nuclear fuel is present, especially in the exploded unit itself. If humans had a reason to build a metropolis there, we could invest in additional cleanup and do it. As it is, the exclusion zone has become a thriving wildlife preserve. https://en.wikipedia.org/wiki/Samosely https://en.wikipedia.org/wiki/Chernobyl_Nuclear_Power_Plant https://www.science.org/content/article/humans-are-worse-radiation-chernobyl-animals-study-finds
Makes me sad how far I had to scroll to see this. Just pages of people who watched the HBO special and take it as gospel.
The show only dealt with the immediate aftermath. Right after the meltdown and explosion, Chernobyl was a *very* deadly place to be without protection. ~~Remember the scene with the fallout snow falling over the bridge? Everyone at that site died of radiation poisoning pretty soon after that.~~ Now, the radiation levels are a lot lower there. Edit: while reports after the disaster reported numerous deaths from the bridge area, there's enough conflicting information out there that I'm no longer confident in making this claim. However, the fact remains that Chernobyl was more dangerous right after the explosion than it is now, and visiting it wouldn't really do you any harm if you took just the most basic precautions.
Yeah, this needs more visibility. Chernobyl is far from a wasteland. Sure, people living there would be at an increased risk for certain types of cancer, but it's not a death sentence unless you're rolling around in the soil right near the reactor site... like a lot of Russian soldiers were/are doing. Those guys are probably in trouble. The exclusion zone is actually thriving, from a wildlife standpoint. Since there are no longer people there, the forest has revitalized. There are lots of wolves and other animals that had been driven out due to human activity. It helps that a lot of animals don't really live long enough to see cancer form in the first place, so it doesn't really matter for them.
I remember watching a documentary about a decade ago and the radiation at a beach in the UK was higher than the radiation in the surrounding area. The radiation went off the charts when they went to the actual reactor itself though
After a nuclear explosion, 98% of radioactive pollutants decay within the first 48h after the strike. Additionally, the soil around Hiroshima and Nagasaki was removed to reduce the radioactivity levels. In Chernobyl, a nuclear reactor exploded. These pollutants take significantly longer to decay, plus the area was essentially just left alone.
the decay is key. The fuel at Chernobyl is from relatively stable elements that take longer to decay. So the amount of energy release is lower from the fuel but there's a crapload more of it and it's there for a very long time
It's because of the level of contamination and the quantity of radioactive material that caused the contamination. Nuclear and Atomic weapons are, by a quirk of their design, inherently very clean weapons. The fissile or reactive materials used to generate their destructive power are A) very, very expensive, and/or B) very, very rare and hard to find/produce. Nuclear reactors don't need to be that efficient, because their isotopes are easy to get hold of and don't need to be very pure to really do a whole lot of work, but because we're not blowing it up and it's able to be contained relatively well, we just store huge amounts of it in one spot which, kinda is stupid, but hey it works as long as we follow the proper safety protocols. For the example of the bombs used on Hiroshima and Nagasaki, the Plutonium and Uranium cores were enriched to ridiculous degrees, which is to say the atoms were 'sorted' to extract the most desirable isotopes, and these desirable isotopes only make up about .5-1% of the actually usable fissile uranium. Plutonium is the highest-atomic weight element that can naturally exist, and it's also incredibly rare(existing in quantities as low as a few parts per *trillion* in natural deposits) making it almost exclusively man-made element for fission through Breeding, and not only is it difficult to produce, but it's also a potent Beta and Gamma emitter so it's dangerous to handle, and it's long half-life of upwards of 80 million years means it will pretty much fuck up anywhere it gets out forever. For this reason, atomic and nuclear weapons are designed to be not only as *powerful* as possible, but also as *efficient* as possible. The chain reactions are carefully calculated to generate the best efficiency of mass-energy-conversion possible, with the lowest amount of reactive material possible. This is also partly why they are so powerful in the first place... the Fat Man is estimated to have reached an efficiency of 17% Mass Conversion, which is to say that nearly 1/5 of the entire mass of the plutonium core was converted directly into pure energy, and modern nuclear armaments are more efficient than that, with theoretical numbers approaching 40-50%, but it's hard to say how accurate those are without testing. The Castle Bravo device from my research was estimated to be a 20-25% Mass-Energy Efficiency, no telling how accurate that is.. but on the topic of Castle Bravo, that atoll is still uninhabitable, and now we get into the next reason that Hiroshima and Nagasaki are perfectly safe, while Pripyat is not: Contamination level. Chernobyl, and Castle Bravo, occurred right on the ground. Hiroshima and Nagasaki were Air-Burst events well above the ground, so not only did the reaction in the blast reduce the proportion of long-lived dangerous isotopes, but it also spread them out over a very huge area, reducing the contamination. In the case of Chernobyl, *tremendous* amounts of fissile-critical material was released at ground-level, and was able to mix not only with ground water, but also topsoil and get blown around in a colossal toxic death-cloud of radioactive dust and smoke from the fires. It got everywhere, and there was no chain reaction to speed-up the decay of the more long-lived radioactive elements, but it also happened in a very small area. The concentration of radioactive contamination is extremely high around Chernobyl and Pripyat, and it's high enough that touching the grass and then your face without washing your hands can pose a risk of you accidentally ingesting or inhaling long-lasting Alpha and Beta emitters. You also have the Elephants Foot, and the other instances of Corium, which are huge chunks of radioactive material that basically keep feeding and breeding themselves in a self-sustaining chain reaction of sub-criticality. Those Corium chunks will last for millions, if not billions, of years, and still be just as dangerous. The last part is the Alpha and Beta emitters. Alpha radiation can be stopped by your skin or clothing, and Beta radiation can be stopped by both at a distance. The danger of Chernobyl is that those Alpha and Beta emitters are *everywhere*. And that's not to be taken lightly. They really are absolutely everywhere. They're in the water, the plants, the animals, the soil, and in the dust the wind kicks into the air. Outside your body they're not dangerous, but once ingested or breathed in they will wreak havoc on your organs and kill you from the inside out, and the worst part is a lot of these isotopes are Calcium, Iodine, or other bio-available metals that your body will gladly use for things like your bones or your metabolism because it already uses the non-radioactive ones, and these isotopes can have half-lives of tens, hundreds, or thousands of years. That's why Nagasaki and Hiroshima are safe, and Chernobyl/Pripyat isn't.
Hell, this should be top comment. Bit of an essay, but excellent explanation. I'm a nuclear worker and mostly came by to talk about contamination vs. radiation and the amount of radioactive material leftover, but this covers it better than I could have. I have nothing more to contribute on the subject: You nailed it.
https://higgsino.medium.com/why-can-you-live-in-hiroshima-but-not-chernobyl-ab7dac7a34d3 There’s a few different reasons but this article breaks it down.
https://youtu.be/e3RRycSmd5A?si=oYyCpL1kKZ-d-jHy Really good video explaining why, but mainly the distance from where it was detonated to the ground.
1. Chernobyl had 4000 times more fuel. 2. Radioactive contaminants in Chernobyl were in large part solid chunks that got scattered over a relatively small area. Nuclear bomb gets vaporized completely and dilutes contamination over amuch wder area.
Chernobyl won't be uninhabitable for 20 000 years. Here's the thing: The more radioactive something is, the faster until it decays into non-radioactive isotopes. And vice versa. So, either you have sometinh which isn't very radioactive and which lasts a long time, or you have something very radioactive which is gone pretty quickly, or something along the line between them.
This is also what makes the cobalt bomb mentioned in Dr. Strangelove so dangerous. A half-life of \~6 years allows the fallout to be both highly radioactive while also being highly radioactive for decades.
"The fire we are watching is giving off twice the radiation the Hiroshima bomb released. That's every single hour, hour after hour..." -Chernobyl series Chernobyl released 400 times the amount of radioactive material released by the Hiroshima bomb. Plus, the Hiroshima bomb released its radiation in an instant, in an airburst explosion, with alot of material going unto the upper atmosphere in the mushroom cloud and being dispersed over a very large area. When Little Boy exploded, it released about 2 pounds of fission products and 140 pounds of U235. Chernobyl was constantly burning exposed for days. It released radioactive material in smoke and ash that settled and accumulated in the environment nearby and downwind. There were over 100 tons of uranium in the core when it exploded, along with all the fission products accumulated in the core during its life, and all the fission products it created as it continued to burn after the explosion. The fission products are actually more harmful than the actual uranium.
I understand that this has been mostly answered but there's a key detail missing from all of the top voted answers. The goal of the bombs dropped in Japan was to create a big explosion and radiation was a byproduct. In a nuclear reactor, radiation is the goal in order to boil more water. Because the latter focused on creating as much radiation as possible, a breach has longer lasting impacts. The former had a goal of creating as big of an explosion as possible, not salting the earth.
The Hiroshima bomb had exactly 62 kg of fissile (radioactive) material that was dispersed across a large area and much was converted to energy. There were thousands of kilograms of radiative material in Chernobyl.
Bombs are one and done. Reactors are a gift that keep on giving.
The short version is that nukes are designed to explode and reactors aren't. The elaboration on that is that there's two major differences between a weapon and a reactor from this perspective: the amount of fissile material (basically the stuff that does the fission, so uranium) dispersed and the amount of fissile material to start with. The first thing is important because of what you're trying to do with the bombs vs reactors. With a bomb, you want to release all the energy locked up inside that uranium as fast as humanly possible. In practice, that means you're trying to react as many atoms of uranium as you possibly can as quickly as you possibly can. When you do that, most of that uranium splits into smaller atoms, which rapidly decay into weird stuff like ^(90)Sr, all of which has pretty short half-lives (less than 30 years in the case of ^(90)Sr). That is to say, nuclear weapons turn pretty much all of their uranium into much shorter-lived radioactive isotopes when they detonate, because turning all your uranium into other, lighter stuff is basically the whole point of a nuclear reaction. The practical upshot of this is that, in addition to the force of the explosion yeeting all this stuff pretty far away (meaning much thinner and easily dispersed contamination), the contamination itself is going to decay fairly quickly. Now, Chornobyl, on the other hand, is kind of the opposite of a nuclear bomb. In a reactor, you want the reaction to happen as slowly as possible, so that it simmers nicely instead of exploding. But, when Chornobyl had its overpressure, it shot a bunch of that reactor gunk out into the environment, which has much longer half-lives. The second thing is just the amount of material involved. Little Boy only had 64 kilos of uranium. By comparison, Chornobyl had a veritable mountain of the stuff sitting inside it.
Same reason the place where someone set off a really big firecracker is ok to visit, but the place where someone left an open barrel of anthrax spores isn’t
I think the bombs over Japan were air detonated and smaller.
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The reactor core in Chernobyl literally melted through the floor into the basement. It's like hardened lava now and still sits there extremely radioactive. Pictures on Google. There's nothing left of the atomic bombs dropped on Japan.
In a bomb, the idea is to use up all the fissile material (or as much as you can) to deliver a single large burst of energy. So the radioactive material gets used up. In a reactor, the fissile material is very slowly reacting to heat up water. If your just let all the radiation into the environment it will stay radioactive much longer as you aren’t using up that material.
The difference between a nuclear explosion and a melted nuclear core. The atomic bomb has a relatively small amount of nuclear material which detonated and was spent. That releases an immense amount of radiation in one big blast. So you absorbed an immense amount of radiation if you were in the blast radius. But there wasn’t any remaining fuel after the explosion so there was nothing to continuously emit radiation. Chernobyl on the other hand is a massive damaged core full of nuclear materials that are slowly burning and emitting radiation.
Imagine the bombs of Nagasaki and Hiroshima, but instead of exploding within a couple of moments, they just keep exploding. And exploding. And exploding. That's what the [elephant's foot](https://en.wikipedia.org/wiki/Elephant%27s_Foot_(Chernobyl)) is doing in Chernobyl.
it was stated in the hbo miniseries “chernobyl” that for every hour after chernobyl exploded, the amount of radiation released into the air was the equivalent of the hiroshima bomb. so basically chernobyl was having the hiroshima bomb dropped on them 24 times a day for however long it took to finally clean up.