What /Actually/ Happened at Chernobyl
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- čas přidán 13. 06. 2019
- This video was so dang fun to research, which, of course, I feel super guilty about because, like, real people died. But, after watching the HBO miniseries, I knew there was more to the science of this. I've also heard a lot of stuff from both credible and non-credible sources that just doesn't hold up to scrutiny. The idea of the "graphite tipped rods" for example is just a simplification for broad audiences. But I've also heard smart folks talk about how RBMK reactors have a positive /fuel/ temperature coefficient, which is not true. No nuclear reactors do, since fuel that reacted more as it got hot would be the kind of thing that would explode every time.
However, for a moment, because water had become such a vital part of the neutron absorption in the reactor, it did have a positive temperature coefficient...meaning that getting hotter made it hotter which made it hotter which made it hotter. That's a coefficient for the entire reactor, and it's due to the "positive void coefficient" where, as the water got hotter, it got less good at absorbing neutrons.
Usually that would be more than counter-acted by the negative fuel temperature coefficient, which is why they thought it couldn't explode...but it was not in this particular circumstance.
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Corrections!
1. Not all of the uranium in a nuclear bomb...fizzes...actually only pretty small amount does before the core blows up and the atoms get too far apart. And yet...it's still a pretty big deal.
2. It's not "fizzes." Fission is both a noun and verb, so uranium "fissions"
3. I imply in this video a little bit that you can't have a light (regular) water reactor with a negative void coefficient...you can, you just need a different fuel / moderator realtionship. There are lots of light water reactors that are much safer than RBMK designs....they tend to require more fuel enrichment.
4. An earlier version of this video got the date wrong and said October 26th instead of April 26. I just removed that line, which is something CZcams lets you do now.
Let me know if you've got anything else I should add here!!
So my birthday is on the anniversary of the Chernobyl meltdown? Yay?
@@desireevelez530 Mine is when the Hindenburg crashed, well I was born a few decades later, but still
I was so confused bc I was sure Chernobyl was in my birth year but over half a year before I was born, causing my mom to worry like crazy about me. (She lived in Germany, close enough to be possibly affected.)
@@naomilovenpeace Mine too. Here's a tip. Turn off the news.
*Unnecessarily Pedantic Alert*
The verb form of fission is also fission. So, U-235 fissions in a chain reaction.
Dyatlov: Hank is clearly in shock. Get him to the infirmary.
Lol
I have seen worse
You didn't see graphite you didn't !!
You Didn't !!!!
@@rishavagarwal5352 "BECAUSE ITS NOT THERE!!!!!!!"
Must be from the feedwater
There is no core
Wait, did you just explain how an RBMK reactor explodes? This man is in shock, take him to the infirmary.
@Rob C you didn't see graphite, BECAUSE IT'S NOT THERE!!!
@Rob C Nah, there are only 3.6 Chernobyl quotes. Not great, not terrible.
@@Werrf1 i’ve told that equals to a chest x ray..
@@EthanMeatan And, by the way, it’s not one chest X-ray, more like… 400 chest X-rays.
@@bradentribble6374 oh I was making a reference to the HBO show Chernobyl! Thanks for the not so fun fact tho lol
"Graphite tipped rods"
Pencils?
yeah, didn't you know pencils are the most widely used type of control rod?
only problem is that the erasers get a little hot.
Bruh
Jake Hildebrand Really?
@@theorange1729 yeah, but it could be because they use those cheap pencils that are made with fake wood
Chernobyl was a graphite moderated water cooled reactor meaning that graphite tips balanced and controlled temperature. Water
also acts as a neutron absorber (just like a control rod) but i think it evaporated + rods were pulled up. They were supposed to be lowered. when engineers lowered it there was 15 second delay, graphite tips reacted by insane temperature increase and that is when explosion happened. Someone who understand this better can explain.
0:03 : no it didn't. This man is in shock. Toptunov, take him to the infirmary.
🙄
He's delusional...🙊
HAHAHHAHAHA
You didn't see graphite, BECAUSE IT'S NOT THERE!!!
this is an elite comment, love it, 10/10
After watching Chernobyl.
You know I am something of Nuclear Physicist myself.
He's delusional. Send him to the infrimary.
lol...myself also!
I didn't know so many people watched this show "Chernobyl" from HBO...its not Game of thrones!!
You didn’t see graphite.
After watching this video, you mean!
Hank saying why does anything exist is how I like to get pumped up for my day.
So how is it working for the organized stalking system? How many people do you harass a day?
@@johng.3740 what the hell are you actually talking about?
@@selloutsanders5774 It is far, far, far beyond you and those who are in the know, know what I'm talking about.
Liked so you’d get to 999
@@bigpeenerpeen Rotate it 180 and you'll understand it better, it has to do with thisssss:
fightgangstalking.com/
Well the "thing that broke" during the SCRAM of the reactor was actually two things: The control rods did move very slowly in an RBMK reactor because of tight fits between control rods and their channels and the reactor is very huge, so it has to travel very long distances, while even a very slight inbalance in neutron generation per fission is a rapid increase of power: 1.01 neutrons per fission on average are a doubling of power every 7 milliseconds. That lead to a thing, the reactor was never designed for: A rupture of more than one fuel channel. This resulted in the reactor vessel turning into a giant steam piston and shooting out it's upper lid through the Ceiling of it's hot box, while pulling out all control rods and evaporating all the coolant at once because of the pressure release, it creates.
For the following burning of the core: Graphite basically is the highest grade hard coal.
Slight correction, it shouldn't be 1.01 neutrons per fission, in fact there's usually a bit more than that per fission. It's the *multiplication factor* slightly above 1 which causes the insane doubling time. The reason that the number of neutrons emitted per fission isn't the number we need to look at is because some neutrons emitted by fission will be lost, either by leaking out of the reactor or by being absorbed by other materials in the reactor. The multiplication factor, on the other hand, takes this into account and tells us how we can expect each generation of neutrons to grow
Had to listen at .75 speed to make my brain work faster. Much like slowing down neutrons to speed up the reactor :-o
Well judging from your comment it paid off and you understood it well
Yeah, i can watch this at 2x speed and that makes my mind go haywire with knowledge. Which i like.
.75 speed. not great, not terrible.
Omg. .75. Yes.
Thanks for the tip!
Thanks for the shout out!
FOUND HIM.
-Play Elite Dangerous with me :(-
thanks for all the amazing content on your channel :D
you didn't see scott manley because he is not there!
How are you not verified?
Hank, this is a great explanation! I can clarify the moderator confusion though. It's not as complex as you think. All you need to understand is that *no atom "smashing" occurs during nuclear fission*. Quite the opposite. The actual reaction is that atoms absorb the slow moving neutrons like magnets snapping into each other. The additional atomic weight makes the atom too heavy to maintain its cohesiveness, resulting in the atom falling apart. That's what we mean by "splitting the atom".
Once you understand this, it's easy to understand why fast-moving neutrons are a problem. They have too much energy to get captured by nearby atoms. It's like the difference between hand-tossing a magnet past another magnet versus firing the magnet out of a high-powered rifle. In the former case the magnetic field pulls the magnets together and halts the throw. In the second case the magnet moves out of the magnetic field too fast for the bond to be established.
Now replace magnetic fields with strong nuclear forces and you've got it. :)
Are you a teacher or something? This made so much sensseee.
Thanks for this!
That helped a lot, thanks
I teach the transport of radio-active loads and I love your analogy. If this subject is your thing it is easy to grasp, if it isn't then the way you have just explained it is superb and I will use it in future lessons. Thank you.
Good explanation! What's also helpful to add is that in the case of U-238, the more stable isotope, it also captures slow neutrons well, but the energy added by a slow neutron isn't enough to excite it so that the electric forces are able to split the nucleus. However, the additional energy from fast neutrons is able to split U-238, albeit with low probabilities since, as you explained, it's harder to even capture a fast moving neutron. What's cool is that when U-238 absorbs a slow neutron, it decays into Pu-239, which is just as fissile as U-235.
In defense of the Soviets regulations for running the reactor stated the exact amount of control rods that were to be in the reactor at all times. Dyatlov broke that rule the computer suggested they shut down the reactor , Dyatlov didn't listen.
The biggest mistake is they did not make the reactor idiot proof.
I am reminded of a comment that was made by the late Major Peter Olver HM Railway Inspectorate in the UK " Nick remember that you can make something fool proof until a bigger fool comes along! No amount of legislation will not prevent someone from being stupid"
Unfortunately Peter's comment is painfully accurate.
To be fair to Dylatov he didn't really know what he was doing. The real problem was the very lax safety culture present in the USSR coupled with a strong "Can Do" attitude at all levels.
@@nicholaskelly6375 Dyatlov was the deputy Chief Engineer of the plant, and had 14 years of reactor experience prior to working at Chernobyl. He was one of THE most knowledgeable people there on reactor operation, he abso-fuckin-lutely knew what he was doing, and regardless had multiple times he could have prevented the accident. It's not solely his fault of course, far far from it, but he played a critical role in the accident and although the scram should have you know, *not* exploded the reactor, he shouldn't have pushed it to the point that it needed to be used.
I do agree with everything else tho lol
@@jacob4012 The real problem was that he didn't properly understand what he has doing.
I once met someone who had worked at Ingalina and it was clear that disaster there (and indeed at Leningrad) was avoided by the skin on its proverbial teeth!
Had the facts of what happened been made more widely available at the other RMBK plants then it is very unlikely that anything would have happened.
Also like any major catastrophe involving technology (RMS TITANIC is a very good example of this) there were several contributing factors which in themselves would have been irrelevant.
But because they occurred in a certain sequence disaster became inevitable.
Thing is unless you tell ppl what will happen if you break the rules most won't take them seriously till something goes wrong or till they're told
Since nobody knew its no shock rules were broken
Well, ppl knew, but said knowledge was covered up to save face aaaaaaand boom (literally) here we are
Nobody operating reactors knew so for all intents & purposes the rules were worth as much as the paper they were written on to the humans in the room on that fateful night
Many of the changes made to RBMKs after the disaster were to lock operators out from overriding key automatic safeguards like they did that night at Chernobyl.
Correction, there was no graphite, BECAUSE IT'S NOT THERE!
and excuse me while i puke my guts up on the floor due to radiation.............. sorry i mean due to the shit cooking my missus does..................................
Donald Duck Trump he puked because he was sick of the lies about graphite being outside the reactor
Only 3.6 Roentgens
@@Anxmaly666 not great, not terrible
@@panitialucky6689 im told its equivalent of 1 chest xray so if youre overdue for a check up...
John: Good! I know how a nuclear reactor works. Now I don't need you.
😂🤣😂🤣
LOL!
TBH in the next shot where they show the Helicopter flying for Chernobyl, I was waiting for a body to be thrown out of the chopper.
@@SunilZishan me too
@@SunilZishan me too...
*Reactor explodes*
Dylatov: “Not great, not terrible”
*Dyatlov
"Well, at least we did the test. Conclusion: The test failed."
The other guy: “not great, not horrifying”
Get this man to the infirmary!
Thank you for this comment lol
Since HBO’s Chernobyl, most of us have become nuclear ‘experts’ ☺️
I also watched Apollo 13. So I'm fully qualified to handle any kind of technical emergency
Senior Reactor Nuclear Engineer.
Chernobyl tv series is total garbage when it comes to accuracy though. Almost everything regarding radiation and nuclear is just plain wrong.
I'm a metrologist, I know what I'm doing. Means I can measure the SHIT out of it.
@@fullfildreamz Historically pretty accurate. Scientifically... Not as much.
I don't know much about nuclear physics and reactors, but I think the words "CHEAP" and "NUCLEAR REACTOR" in a sentence is not the best idea in most cases
Edit: I cant believe that i need to to mention it explicitly, but here we go... THIS IS A JOKE!
Shivam Kulkarni actually, the price of energy in nuclear is only 1.82 dollars a KWH house. It’s because the fuel is incredibly cheap. The reactor is expensive but that easily runs for 50-60 years. So the write off is minima.
Governments always squirm when the hear the average of 12 billion for large nuclear power plant. But they forget that it can run for 50 years without costly maintenance. So it’s actually relatively cheap in the long run.
@@rdoetjes Thank you. I really didn't know about these numbers. And $1.82 sounds like an awesome deal anyday! But since the reason we're talking about it is one of the greatest nuclear tragedies yet, it seemed like a good joke. That's all. I'm an engineer myself and I know the importance of "cheap" very well.
And the word "fast" shouldn't be mixed in there either.
@@tudorjason that is usually referring to neutron speed, if im not mistaken. It's not the speed of the reaction, which I agree, could sound reckless
Exactly why Soviet Russia no longer exists
I majored in Physics at university, and you've done a really good job of explaining each term and each process step in a coherent way for the general audience - well done Hank :)
How would you know, you studied physics a university?
hashtag woah
@@alex0589 I did a module on atoms, photons, and fundamental particles, which included nuclear fission and nuclear reactors. I don't claim to be a professor nor do I have a PhD. I just wanted to thank Hank for his time and effort into this video because it was good science communication, from someone who has gone through a standard undergraduate university course.
@@yozul1 He's probably right in that respect! Regardless though, I just wanted to highlight it was more the fact I liked Hank's delivery :)
Well I'll settle this...I'm getting my PhD in nuclear engineering....and I think he did a great job simplifying this. There are a few things I'd add to his theory/first portion of the video like for example how we could have other types of fuel (U-235 isn't like the only "holy-grail" we could use...we could use natural uranium for example...ask Canada about that).
However...his explanation was excellent (in terms of simplifying things at least), and good in terms of technical fidelity....he left out the part in Chernobyl about the design flaws of the RBMK (the reactor), which also had a hand in the disaster.
Soviet designs favored performance over safety....that's a big NoNo for nuclear work where we prioritize safety. They more specifically, favored Plutonium production over anything (for political reasons obviously).
For example, he mentioned how the top blew off in the reactor....yeaaah this was a design flaw in their containment that they saw as a means to save $...which obviously was a bad decision.
You can Google most of this stuff...it's not a cover-up (not anymore at least), so you can learn about all this stuff. But the thing to take out of this is that the nuclear industry is constantly reminded and learns from its mistakes...and while nothing is 100% safe (not even renewable energy), the industry and nuclear technology in general...with newer reactor designs being built everywhere in the world is much...much safer than Chernobyl, and any other energy industry you can think of nowadays (yes, more people die yearly from working on wind turbines than they do working in a nuclear power plant).
Hey, thanks!
I missed explanation videos! These are the best! +4 minutes of good content right here!
For sure! I wish there was a whole channel for this! I know, there's SciShow(s), Crash Course, and I love them, but honestly nothing beats Hank or John just talking to me from their rooms. Nice graphics, too! Fancy, fancy.
Hank, I took the NYS chemistry regents two days ago and there was a question on “heavy water.” All of my friends were quite confused, but I calmly answered the question thanks to my interest in this video! This, combined with crash course chemistry, were very helpful in my exam taking! Thank you as always!
You're wrong with your definition of Neutrons.
It's *B U L L E T S*
they won't stop firing for millions of years
So u watched Chernobyl on popcorn time or smth
Get him to the infirmary
Hundred of millions of billions of BULLETS
This made me cackle
This explains why for the last two weeks all of my CZcams recommended videos have been either about the marblelympics or chernobyl.
p.s. great video. I learned so much! -John
It's Limetime
czcams.com/video/QmJN-LMPnX0/video.html scared of nuclear? Galen Winsor wasn't... he eats radiation for breakfast!!
Good morning John.
So disappointed in the Oceanics this year
TIL that John does his casual CZcams browsing on the Vlogbrothers account. Imagine being a tiny channel and uploading a cake baking manual and suddenly Vlogbrothers likes it
Thank you, this was the first time I learned to understand what has happened. My dad was on the medical team at cleanup. Luckily, got no lasting ill effects.
Wow!!! Your dad is a hero and so is everyone who sacrificed themselves in this incident. God bless him!
Thank your dad for me for helping to save countless lives.
I was 5 when Chernobyl exploded. So many unsung heroes.
Does your dad feel that Soviet authorities were trying to cover up the incident?
@@Lionfish5656 Nah, he was not long after the compulsory service, so extremely loyal at the time.
Gosh, this brought back warm fuzzy memories of me in Nuclear Power School thinking I was going to fail for sure. Unfortunately, I passed and realized how much it sucks to work in the engine room of a submarine.
no it doesn't, you're in shock. Take him to the infirmary.
That was a really great description of why the control rods were "graphite tipped". Because the oversimplified explanation just makes you go "WHY WOULD THEY DO THAT?" But seeing your diagram and what actually happened made it make sense. And it WOULD have been safe if they followed their own safety procedures.
Agreed. “Soviets stupid, evil and CHEAP” makes for better television, though.
Today's XKCD alt-text gives a pretty clever analogy to explain Chernobyl: "You know when you can't hear your speakers, and you keep turning various volume controls up higher and higher in confusion, and then someone hits the mute button and there's a deafening blast of sound? That's basically what happened at Chernobyl."
I think it's more like when you're learning to drive a stick shift and you feel it stalling, so you panic and just fucking floor the gas pedal while letting totally off the clutch at the same time and you peel out and wrap the car around a utility pole :D
@@RoboBoddicker This is funny because I'm learning stick shift & I done this in my lesson today LMAOOO
@Edwin Davies Would a metaphor for this be like trying to compare how you feel after a glass or orange juice and how you feel after a glass of apple juice? Hmm, you know, when I'm hungry I always think of food based metaphors, and right now, I'm dehydrated! I better get me a drink!
It's more like when you're commenting on a You Tube video and then you don't see your post, so you smash the submit button again, but then you double post. But completely different.
Or pulling a nail with all your strength and it detaches in a single instant making you fly against a wall
Akimov: The reactor is about to blow we have to shut it down right now
AZ-5: Ima bout to end this man's whole career
TheBanjoShow whole life lol
Im dead :D :D :D
@@peterkolesar4020well the man who press it is dead lmao
AZ-5 : imma bout to end this town's whole career
Because cirilic A3-5
Cpt. Mcmillan - “50,000 people used to live here, now it’s a ghost town”
Est. 2007
Imagine how many more people would/could be living there today.
@@evalynn1863 Since many areas of Russia have a birthrate less than 2.1, and a declining population, probably there would be less people there than were living there in 1986.
@@xWHITExEAGLEx you know that Pripyat and Chernobyl are not in Russia right?
@@hrvojenakic-alfirevic8924 I do, shit, don't know why I wrote that, must have been sleepy.
@@hrvojenakic-alfirevic8924 That's what I get for being a smart-alleck.
The HBO show be like:
Power Plant Worker: "So wtf do we do with the crossed out instructions? Do we skip them or what?"
Control: "follow the crossed out instructions, ignore the rest"
Power Plan Worker: "for real? Are you sure? Why..."
Control: "Yeh, trust me bro"
*Reactor explodes*
Nobody wanted to be responsible for failing the safety test again, AND causing the reactor to be out of operation for 2 days. Nobody wanted to lose their job or be sentenced to labor camps :P
Well the Soviet Union was changing radically when Gorbachev was in power
Crossed out instructions? There was no such thing. That's part of the problem.
@@KarlKarpfen It was portrayed like that in the HBO show. It might not have happened like that historically. TV shows love to embellish things to make them more dramatic, I suppose.
@@Fantastic_Timez Yes, but history tends to be remembered like it was portrayed in films and TV shows.
As a Nuclear Engineer (by training), that was perfectly succinct for the depth required to accurately describe reactor design. You never said the buzzwords though! "Positive Void Coefficient of Reactivity." We talk about things in cents and use symbols like β (no, not that β, a different one), its so much fun! Still, the thing both your video and Scott's made me aware of was that it didn't *always* have a positive void coefficient, only when operating with all the control rods out.
One nitpick: neutron flux is actually neutron flux density. Neutrons aren't stationary, they've moving all the time; talking about a static population density doesn't make sense, so we think about "flux density" which is the Number of Neutrons * Velocity / Volume, so n/cm^2/s, and even though its defined with a 2d perspective (1/cm^2), most reactors have isotropic scattering so its the same in all directions and you can just think of it as "neutron density".
There is such thing as static flux density distribution. Just write down the equations and set time derivatives to zero, and every solution of what remains in the equations will give a static distribution.
@@u.v.s.5583 so, ignore that time exists?
@@SteveisTall Not at all. It is a dynamic equilibrium. Energy flows from region to region, but the fluxes cancel each other out so that the distribution of the flowing physical quantity (neutron number density or whatever) remains stationary.
Its OK to neglect the density word for explaining to physics noobs.. But I agree it is useful for completeness...
E.g. you could say there are a lot of people passing through a gate, causing congestion... But scientifically speaking it's that the density of people moving through the area of the gate is too high, and too many per unit of time (too frequently), a higher density and regularity/frequency of people movement than it was designed for, and the number of people passing through a gate per second doesn't determine congestion, only the density of people per second getting high enough causes congestion in any gate, no matter which gate or what its size is..
You can still say there's too many people trying to pass through the gate, rather than saying the density of people trying to travel through the gate is too high, and too frequently too many per second..
So yer, he got the flux bit which indicates "per second" and the density bit would have meant "per unit of surface enclosing it's volume", which matters for calculation, but not so much general communication.
If people talked about electron flux when discussing e.g. a copper wire overheating due to the resistance of the wire to electrons passing through it, people would understand what you mean by saying too much electron flux rather than saying electron flux density.. We know which part the electron are flowing through, the volume being discussed I.e. the wire.. In case the word "current" didn't exist.
Its also OK because he said the "neutron flux was too high in this part (the bottom) of the reactor", which is in fact understandably correct, as that part is a known volume, and so the high neutron flux density will have a defined total neutron flux, which will also be "too high" for this part of the reactor.
What's the other B
At 11:45 “and so... and so, and so...”. My favorite line reading of any video. More Vonnegut than Vonnegut could ever Vonnegut.
“It’s not 3.26 röntgen......it’s 15,000”
Dyatlov: not great, not terrible
I think you are mistaken comrade. RBMK reactors don’t explode.
Disgraceful really, spreading disinformation at a time like this.
If you watched the Chernobyl series you would get the joke, It’s a quote from the movie😂
@@rishabram4389 so is the disinformation line. Viktor Bryukhanov to Valery Legasov. When he says "explain how an rbmk reactor explodes".
Adam Hussey Yes and Valery’s response at that was that he didn’t know because nobody knew exactly how it can explode at that time. My quote was to show the irony that Bryukhanov and other Russian Nationalist at that time could not believe that the core could explode in an RBMK reactor. Calm down boomer😂
@@rishabram4389 first of all I'm not a boomer. Secondly even if I was you'd still be using that term incorrectly. And thirdly I simply pointing out that it is a line from Chernobyl and that you're wrong, something I'm sure you hear a lot.
Dyatlov: "How does an RBMK reactor explode!?"
Google: Here's a vlogbrothers video for you, comrade.
Too bad they’re some 30 years apart.
Commrade Kenneth, are you stupid? The Vlogbrothers are delusional.☢️
@@jamesricker3997 Actually, so is anybody who says "vlog", meh.
“YOU CAN’T EXPLAIN IT BECAUSE IT’S PHYSICALLY IMPOSSIBLE.”
@@endurovro Oh yeah that's what you think
i love that hank went so deep into what was the problem with the reactor
where i was like : there was much heat things went wrong and caboom
I literally enjoy learning ANYTHING 10x more if you or John are teaching it, Hank. God bless you
Best explanation I saw thus far.
Chernobyl is a bit of a passion of mine. As it led me to prove for my physics exam piece that nuclear power is dangerous and how we should avoid it. Only to find out the opposite. And people are wrongfully scared. These situations like Chernobyl and Fukushima are rare and impossible even with modern fast breeders. To keep fission happening there it’s like riding a unicycle, whilst rubbing your stomach and juggling. What stunned me the most, is that for the most excessive deaths estimate of all 3 nuclear reactor disasters. In the worst case 8000 people died. Whilst 8000 people alone die in The Netherlands of fine dust alone. Often from coal and oil burning. And nuclear reactors safe about the same amount of lives almost weekly. Due to its isotopes being used in medicine to cure people from cancer.
While probably lot less deaths than other energy sources, mining uranium probably kills a bunch of people.
I do agree that Nuclear Power is pretty safe now, situations like Chernobyl are almost impossible once all outdated reactors are finally decomissioned. Modern reactors are passively safe. Coal and oil is just stupid...
The number of direct deaths from the Chernobyl disaster was low, but the number of people affected by the aftermath was much higher: "According to Vyacheslav Grishin of the Chernobyl Union, the main organization of liquidators, "25,000 of the Russian liquidators are dead and 70,000 disabled, about the same in Ukraine, and 10,000 dead in Belarus and 25,000 disabled", which makes a total of 60,000 dead (10% of the 600,000 liquidators) and 165,000 disabled"
@@mephistophelesfussli819Probably no more than mining coal does, tbf
Hey John can you explain the amendment of extradition bill requested by Hong Kong Government, which caused 1 million citizens to protest at 9th Jun last week.
It means a lot to Hong Kong people!Thanks.
seconding this! there's a lot of misinformation being spread by the chinese gov't, and western media has not been fully covering the underlying issues. but also, 2047 (the year the 2-system, 1 country agreement expires) is coming up, and I wonder how inevitable china's actions are.
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You DIDN'T see the reference on the video because it's not there!
*projectile vomits*
EW! I didn't order a salad covered in radioactive vomit. I want a refund.
Blogbrothers: I apologize *Collapses*
That's not granite
Damn, Chernobyl memes are too high down here in the comments.. I think we need higher capacity of dosimeter..
@PLOMBIR I like your too, Laughingman Clan..😅😅
Use the good one, out of the safe.
Three thousand _Chernobyl_ memes, not great not terrible
They bring us Faulty equipment and expect us to curb our memes?
Thank you, thank you, thank you! Have been reading/watching/listening to so much material to try to understand what happened in Unit 4 at Chernobyl, and this is by far the most succinct and approachable explanation I've come across. Again, thank you!
Hey there! So i actually work in nuclear power, in fact I'm currently sitting inside a nuclear power plant watching this... I just wanted to pop in and say thank you for not painting the nuclear industry big mean and scary! Chernobyl was unprecedented and because of the safeguards in place today unrepeatable, I really appreciate that you took the time to explain how everything went down! DFTBA
@Adarsh kumar
3 questions:
How many people have died due to nuclear waste not being handled properly? How much nuclear waste is stored around the world? Where is it stored?
I think those 3 pieces of information ought to demonstrate the accuracy of your claim.
Spoiler: it isn't accurate.
@Adarsh kumar
You still haven't answered my 3 questions I see.
Abby Baum, hey man, how about paying attention to the reactor and when your shift is over then watch yt😅😓
Your sitting in taco bell
@Adarsh kumar "all you had to do was search, are you here to test my competence or to get educated?" You made the claim, you are the one who needs to prove it. I notice your entire comment was assertions, no links to anything that proves what you said.
Great video! I have studied Chernobyl since ‘97 and this is one of the best ways I have heard how to explain the cause and effect of this disaster to someone who may not understand the exact physics
A note on explosions. They absolutely do not require a phase change. You can get an explosive by pressurizing hydrogen and oxygen gas, which react to form steam/water vapour, also a gas. An explosion is primarily about pressure and energy.
Three Mile Island: I'm going down in history as the worst nuclear disaster in human history
Chernobyl: hold my vodka
TMI wasn't even that bad, outside the reactor itself atleast. Yes, it had a partial meltdown, but the containment structure did it's job like it was designed to in the first place. They got very close to a full meltdown, and also a hydrogen explosion, but thanks to the reactor design they were able to mitigate those issues.
@@DrakeKillah ye but at that point (not counting Kyshtym disaster which wasn't revealed until after USSR fell) it was the worst nuclear energy related accident.
Granted the damage was limited to plant itself BUT it obviously made it impossible to use that reactor ever again
@@DrakeKillah just one partial meltdown?
RBMK: Hold my beer! ... partial meltdown in Leningrad-1, partial meltdown in Chernobyl-1, catastrophic failure of Chernobyl-4
Please tell me how an RBMK Reactor Core Ex-
Wait nvm
it didn't you are delusional!
It didn't .....it didnt happpopppenen (shouting)
TheIdiotNextDoor RBMK reactors dont explode. Youre delusional go to the infirmary
Lies...
Saw the Scott Manley video first.
I really think the neutron flux diagram added to my understanding.
In layman's terms, the reactor is like a diesel engine. Rather than using the accelerator pedal to slowly bring the engine up to speed, they took the governor off and set it to wide-open-throttle. It started to overspeed and their "solution" was to try to slam the intake closed. And not only did it completely destroy the intake, it blew off the cylinder head in dramatic fashion and caught on fire.
(Obviously an oversimplification, but I think it fits).
Caleb Shonk that's pretty good
Ah! Thank you. I'm a gearhead, not a physics buff so THAT I understood.
Great comment. All I will add is that the reactor has only one cylinder, the piston weighs 100 tons and the cylinder head (the upper biological shield or as the Russians say " the pyotachok " or 5 kopeck (nickel) piece weighs 50 tons.
Absolutely fits as a simplified explanation. It's not perfect, but it gets the point across with an analogy to something people are more likely to understand 👍 It doesn't explain the xenon poisoning, meltdown and following steam explosion, but it doesn't have to.
Actually this can happen in Diesel engines. It’s called a “runaway” diesel and since Diesel engines are controlled by regulating the amount of fuel that goes in rather than air like a gas engine they will keep going a diesel in runaway sometimes getting so hot they will start combusting elements in the air itself and engine oil and the only way to stop it is to choke off the air intake and hope the engine is sealed enough that air won’t be sucked in elsewhere as the faster an engine is running the more air it can draw in (why Diesel engines don’t have a safety valve that can close the intake I don’t know but runaways are rare and usually only happen with poor condition engines anyway. Shitty explaination probably but to understand it requires understanding how a Diesel engine works but they rely on heat and compression to ignite the fuel
Gas engines can’t runaway because they need fuel within a certain tolerance air and importantly a spark. I think it’s near impossible to detonate fuel in a gas engine on compression alone
Its ironic and borderline Kismet that i watched that Scott Manley video FIRST, then found this video. Now, having watched Scott's in depth video first, and then this slightly watered down version I feel like I understand Chernobyl better than if I only watched one or the other. Thanks guys!
Understatement of the century: “... the top popped off the reactor...”
Well, it did, due to steam pressure. Had there been no second (much stronger) explosion, the damage might have been much less.
@@maksphoto78 it did not pop. It literally got obliterated into another dimension
@@ju.h_man No, it popped up due to steam pressure. It was just enough to damage the reloading machine, and let oxygen into the reactor, which cause a much, much more powerful hydrogen explosion. That explosion was what obliterated the central hall, making the 1.2 meter thick walls literally disappear.
Yes, the several thousand tonne top
No the lis was thrown up into the air and then landed back down on its side back into the reactor it was blown through the roof then the massive explosion occurred
In addition to all the harm done to the environment and human life, Chernobyl made the world scared of nuclear power. I theorize that if the Chernobyl disaster didn't happen we'd have more nuclear power plants today and a smaller carbon footprint as a result.
Yes, you're probably right. But it did blow, caused an unbelievable mess, killed people.
Bottom line, if fission power were safer, people would be more inclined to use it.
@@baruchben-david4196 it IS safer.
I believe Three Mile Island and the "China Syndrome" movie had already started the scare, at least in America.
Thank you!! I loved the HBO show and as a completely non-science person, I still tried to do as much research on this as possible to understand, at least in layman's terms, what really happened. You are the first person that has actually helped me to understand the graphite tips thing. The only explanation they gave on the show was that they used them because it was cheaper. That never made sense to me and I never understood why the had to have "tips" on the control rods in the first place. Thanks, again for helping clarify this.
The longer explanation is that it is cheaper to have the moderator and absorber on the same rail system. More expensive and more complex to have them on separate systems. However, when on separate systems, you cannot have the type of disaster occur like that which occurred at Chernobyl.
++
Totally loved this one. Thanks so much for making it. :)
I always disliked physics in school, but now I realize that it was just because I didn't have great teachers.
You need to learn the boring basic stuff to understand the more interesting, advanced stuff
Not all physics deal with exciting stuff like nuclear reactors though :P
I'm a physics grad student and one of my professors worked in a lab near chernobyl during this time. he's told us a lot of stories from living in the soviet union but by far the scariest ones are from chernobyl. he said the number of friends that he had die from the disaster was in the double digits. he remembers working in his lab and the kgb going door to door taking any equipment that could have been used to test how bad it really was, but he got to his office, put his coat on, stuck a radiometer under his arm, and snuck it out of there. he said he measured radiation levels that were 100 times higher than what the government was claiming they were. and once he got over to america, he wouldn't take any assistance from the government, even though i think he was essentially a refugee, because he didn't trust any government at that point.
on a slightly lighter note, he said he made a satellite dish out of a metal sled, like one of those disk shaped ones, so he could watch tv. also he has a very strong accent so sometimes during lecture he has difficulty saying some words, but one time last fall he said "yknow i dont think our president could say that word so its fine that i cant either."
@@no-one-in-particular mmmm yes, saying the president cant say "infinitesimal," what a sick burn, how dare he insult the president like that
@@no-one-in-particular What's so bad about it?. The freedom to do just that is what makes free countries special. If you're implying in some ways that he shouldn't/couldn't then that means he very well could've staid put in the USSR...or that the US isn't that different from it to begin with. Which isn't the case. Freedom to be able to think whatever you want and say as much is one of the reasons the US was born to begin with. Question that freedom (be it in US-born people, or by assimilated immigrants), you'll stop being what you are supposed to be.
Your call.
Oh and now we're at it I highly doubt the current president of the US was president when that guy moved into the country.
@@ramjb "Freedom to be able to think whatever you want and say as much is one of the reasons the US was born to begin with"
Why did they kill MLK again?
I'll let you pick the next category, Alex.
@@ShortArmOfGod thank you.
Thanks for posting this! I was curious about the science behind the explosion but when I tried to read about it, it completely flew over my head, i have a little grasp on it now!
You guys don’t know what you’re talking about! RBMK reactors can’t explode! 🤦♂️
Right, this guy is delusional! Take him to the infirmary.
Everyone after watching Chernobyl:
You know, I'm something of a scientist myself.
I needed 13 minutes of vlogbrothers today even if I learned all about this in one of my classes. Also, Fun Fact: Fission is a noun and a verb.
+
Fun fact part 2: the related adjective is “fissile”!
How it a verb
Katelynn Murphy Because the English language is stupid.
@@1992ilikepie The same way words like partition or requisition are both verbs and nouns.
Great vid. Your enthusiasm makes me wish it was about 30 minutes long
Actually, an "explosion" is just a "relatively rapid" variation in volume. it does not have anything to do with phase change. I can assure you that a oxy+hydrogen tank can explode as well and they are both gasses.
The rapid expansion is usually caused by combustion which add a lot of thermal energy to the mix, and not by phase change.
Also, to be extremely precise, "detonation" is the world you were looking for. deflagrations are explosions as well, but expansion occurs slower than the speed of sound.
"Something isn't possible" - Said by someone, right before something happens.
And yet we continue to think this or that isn't possible.
You're delusional. Take them to the infirmary m
Oh shit
Unsinkable. Unbreakable. Impossible. We should stop using those words. It's just asking for trouble...
One of the detailed applications of Murphy's Law. If something bad can't possibly happen, it will, at the worst possible time.
Fun Fact: The original Murphy's Law was only "If a part *can* be installed wrongly, it *will* be installed wrongly, sometime, by someone." The statement came from aircraft repair mechanics during WW2, which also gave rise to the word "Sprog" meaning an apprentice aircraft mechanic who had yet to learn the difference between a sprocket and a cog. Later, it referred to anyone young and inexperienced before lapsing into disuse in recent times.
Thanks for including a link to Scott Manley's video, nice work on keeping it simple,still early hopefully this thread doesn't get filled with the anti nuclear hype.
I was hoping he'd reinforce the goodness of Mr. Manley's video.
Explained very very very well :) hours and hours of research of this, and u actually still managed to tell things I didnt know. :)
Hank this is a seriously AWESOME video. I learned so much and I've watched the show! Thank you!!!
"Good. I know how a nuclear reactor works. Now I don't need you"
No really though. This explanation was much appreciated. I just watched Chernobyl yesterday and that graphite tip thing was bothering me because it seemed too stupid to be the whole story and I hadn't gotten around to looking it up yet.
punkinholler me tooo !!! During the court session , I was like “ who in the world would tip it with graphite “, even though he explains it is cheap and so they preferred it!! I was not satisfied
No one says that the graphite tip thing was the whole story. No idea where you're getting that from.
@@somolsunny337
Think of the graphite tips like spark plugs in a car's engine; the petrol might be hot enough, but still needs a spark to get the tiny explosion for running the engine.
We actually just learned ab fission, fusion, radiocative decay, isotopes, and some related terms in physics 1 so i actually understood some of this!
You’ve explained this simply, much better than anyone to date, even Scott Manly, and better then the scientist portrayed in HBO show. Gas and brake analogy is excellent. Thank you.
Thanks for the info. I got to tour the site in Sept 2019 and am drawn to learning more
Damn, at about the middle point of the video I was sure I was lost and that I would either have to rewatch this video a few times or just outright give up on understanding what happened, but at the end there somehow everything you talked about fell into place and I experienced a moment of clarity and understanding I have not experienced since I was a kid. Props to everyone who contributed, in any way, in writing this video. I am truly thankful!
Hank thank you for always making learning interesting!
Although I got an M.Sc. in chemistry I had still been able to understand the physics involved prior to your video. It took some time.... well done! Great job you have done!
Btw: In my country we had light-water reactors as well... 😉
I loved the TV series, thanks for the in-depth explanation. Very informative!
"Whyyy? Forces? I guess?"
Same, Hann, same.
And I'm studying physics 😂😂😂
The biggest issue with Chernobyl was that they actually knew about this very specific lost of things or at least suspected but suppressed the information.
Yeah they knew, and no-one wanted to be the guy to stand up and say: "Yo, we need to redesign this, even though it's expensive" Back in The Soviet Union 😂
Agreed it was extremely dangerous the information was kept from them.
But it doesn’t excuse the hours of blatant misuse of a nuclear reactor leading up to the very situation that information would be relevant.
The biggest issue was the positive temperature coefficient of reactivity.
They did have a situation before in a different reactor where the AZ-5 (SCRAM) button was pressed, and a momentary power spike was recorded as the water was displaced, but it wasn't enough to cause it to go prompt critical before the boron took over.
Learning about the 'tips' was very helpful. Thanks!
I’ve made this point several times, but if you truly know a subject, then you should be able to explain that thing to any person with any level of knowledge. This is a great dumbed down video for people who want the gist of what happened without having to strain too much. I think you could probably explain this to a fourth grader in a way they could comprehend. Thank you very much. This explained much more than Chernobyl HBO series, which explained much more than any video up to that point that was comprehensible to a lay man. Thank you
HEy its a me MARIO!
Me: _watches Chernobyl_
All my gamer tags 1 day later: *RBMK_Reactor*
He's delusional, take him to the infirmary.
Made me lol.
Rbmk: Russian badly made krap 😁
123rd like 😂
players who end up in your team: Aight, I'mma head out 😳
RBMK reactors are perfectly balanced, as all things should be.
Dyatlov: Hold my vodka.
Thanos’ favourite reactor
You are a maron,
RBMK has the huge defects
What an excellent video - not least the explanatory introduction. Thanks!
"So hot that it, in fact, dissociated into hydrogen and oxygen..."
This description of the development of H2 and O2 in the steam-pressurized reactor strikes me as a little too simplified. My understanding--and I've seen the HBO series twice, mind you--is that the zirconium jacket around the fuel reacts with the steam to form hydrogen.
No one knows for sure exactly what sequence of (chemical) events led to the two explosions, but I've always imagined that the first, smaller explosion was related to the compromise of the reactor top due to pressure, while the second explosion was the bulk of the hydrogen that had been formed inside the reactor finding the needed oxygen when the top popped.
In any case, the "dissociation" of H2 and O2 is, I believe, the result of a chemical reaction between steam and zirconium at high temp. I only bring this up because your description makes it sound like the water molecules simply break apart.
You are correct
I usually find physics very difficult, but you explained it very well. Thank you for posting this video.
Watched Chernobyl. Came to CZcams for more info. Bam! Hank does a video on it.
Tremendous explanation of the disaster. Especially the graphite-tip clarification.
This is the stuff I subscribe to you for. Thanks.
"Reactor design is all about creating Balance"
Sounds like Thanos but ok.
Who is thanos?
@@jaellanthehat3693 Ever heard of any movies with the title "Avengers" in it.
@@Josh-hr5mc One
@@jaellanthehat3693 I'll do you one better.. Why is Thanos!
@@RRSmurf what?
I failed honors chemistry this year and this made sense to me. Thanks Hank, for making extremely hard concepts suddenly so beyond simple.
this is a rlly cool video i love learning about the technical sciencey stuff
Fantastic explanation, although most will need to do some reading ahead of time to make it comprehensible (which I had done, in connection with reading THE MAKING OF THE ATOMIC BOMB, by Richard Rhodes -- highly recommended).
Thanks so much for covering the smaller points not possible in shorter videos, and describing them so well!☺️
I think the reason I’m so early is because notifications haven’t/aren’t showing up for this vid. Love the vids, shame that some people will have to wait a while or seek this out bc it’s really interesting.
CZcams has been effing up with the notifications lately
@@rozempire2843 By lately you mean for the last 10 years right? :D
Chandler Ferry Haha, yeah, that’s exactly what I meant
Is this the guy that did "crash course" the biology channel?
If so thank you so much I got a distinction in every assignment because of your videos! Love how you teach 💓💓💓
This is in fact the guy
You're the second "how it happened" vodeo after I fell into this rabitt hole. Your explanation of the 2 seconds of rods and how they were used is by far the clearest I have seen so far. Also read one appendix to an IAEA document that has translated Russian report from way back then. One component they mention is that when they turned off the turbine and only ran the pumps (as part of the test), there was less cooling happening and the water being pumped into reactor was getting closer and closer to boiling point at that pressure (about 1000psi as I recall), and eventually flash boiled.
thank you for this - started watching the 1st episode of chernobyl and i didn't understand what was going on.
(also, been a while since i visited this channel...maybe i can start watching again~)
You could've just watched the whole show though, it gave a simple explanation atleast :P
This is the best explanation I have heard on the how and why of the explosion at Reactor 4 for us non-physicists. Thank you!
You are mistaken. RBMK reactor cores don’t explode.
Saw Scott's video first. As informative as it is, and as much as I was able to understand the sequence of events that led to the explosion (I'm a historian, not a scientist, so the crucial bits went over my head), your explanation of the neutron spike at the very end made it much more understandable. I went back and rewatched Scott's video and was able to better understand his explanation of the neutron spike. Between the two of you I now have a clearer picture of what happened.
I was 13 years old when it happened, and watched as it all played out on the news back then. But only now, 33 years later, thanks to HBO, and thanks especially to you and Scott, do I know the full story about what happened then and, more importantly, how it happened.
We're a good team!!
By far the best explanation of the Chernobyl reactor control rods, their construction, and their role in the nuclear disaster. Long overdue.
I am watching the Chernobyl series on HBO. Your explanation of the dynamics of the event were invaluable to me and is making my enjoyment of the series way more intense. Mad respect from Virginia 👍✌️
vlogBrothers: *makes a video explaining the Chernobyl incident*
comrade Dyatlov: "not great,not terrible"
You've got the date wrong in the beginning Hank. You said "October" and it was actually April 26, 1986 😊
I was just about to say that!
He has acknowledged that in a comment.
@@speedy01247 ...and fixed it.
Dyatlov:I am inevitable.
Button:And i am AZ-5.