CHERNOBYL AZ-5 why it exploded

A visual explanation of why Chernobyl's RBMK reactor exploded with meticulously modelled 3d animation without going overboard on reactor physics. This was the worst case example of nuclear power going awry.
Explained are:
The role of the AZ-5 emergency shutdown button The end effect design flaw
Xenon poisoning
The actions of Anatoly Dyatlov.
Graphite moderator.
The reactor lid "Elena" or upper biological shield is shown being thrown by the explosion.
The main systems are explained, reactor, coolant circulation pumps, steam separators and turbine generators.
The control room is visualized and location of the AZ-5 button is shown.
The explosion scene has been simulated and recreated. There is no footage so it's my best guess of what the explosion looked like.
0:00 Intro
1:18 Systems
2:13 Graphite
3:12 Control rods
3:56 Design flaw
4:28 The test
5:42 Xenon
6:32 AZ-5 button
8:44 Explosion
9:43 Accountability
11:01 Safer reactors
Music by Borrtex:
Process, Light, Fog in the street, We are saved, Universe, Wondering, Light.
Software:
Blender 2.83
Hardware:
CPU: AMD Ryzen 7 3700X
GPU: NVIDIA GeForce RTX 2070 S
#Chernobyl #RBMK #AZ-5 #documentary #explosion #blender #nucler power

[@venator5]

When the button supposed to kill the reactor takes the word literally.

[@crazeelazee7524]

"Kill it" "Very poor choice of words"

[@williampittam1]

And that there is the self destruc... I mean rapid shutdown button yeah yeah that's what I meant.

[@carombonation]

@@crazeelazee7524 kill it with humans

[@DRDREAMYBULLMDSBROTHER]

@@williampittam1 you mean have a no life zone fast button

[@williampittam1]

@@DRDREAMYBULLMDSBROTHER ehhh same difference

[@xaviersands999]

“Fireman said they warmed their hands over the graphite on the ground” that gave me chills

[@retrocompaq5212]

their hands did not burn after 2 min like the stupid and fake uk serie

[@xaviersands999]

@@retrocompaq5212 uh okay was still a good tv show though

[@brentfarvors192]

@@retrocompaq5212 Ok, but it was just slightly exaggerated...They fell off 4 hours later...The deaths were also greatly under reported. NONE of those that were initially on the scene up to the 5 week mark, are alive today!

[@23GreyFox]

@@retrocompaq5212 Shut up.

[@adam.2004.4]

@@retrocompaq5212I think It's a good miniseries

[@karlkarlsson9126]

Interesting fact: Sweden was one of the first countries to notice that something had gone terribly wrong when the workers at a Swedish nuclear power-plant couldn't go through their own detectors without having them going off, they thought there was something wrong with their detectors until they tracked the radiation to Chernobyl, and expected the worse, so they picked up the phone and called them and received an answer that everything was OK and nothing bad had happened, so then Sweden called the US and explained the situation.

[@maddddddduu1433]

Xx

[@michiv334]

True. I remember that very well. At that time I was a freshman at the college. On the May 1st the college authorities told us to go to an athletic event in order to celebrate the Worker's Day, as Poland, my country was ruled by communists those days. So we were carelessly playing soccer and nobody was aware that radioactive dust was shining at us from above, since the Soviets kept the disaster in secret. Thanks to those open-eyed Swedish guys Europe received the warning. Next, all countries implemented suitable security measures which probably saved thousands of lives.... Soviets/ Russians have never taken care about human lives, so they kept all in secret for propaganda reasons. Today, we all see that nothing has changed in their mentality up to present days... Hadn't those Swedish fellas spill the beans, many many people would die or suffer from radiation syndrome. And maybe the Soviet Union would't collapse so quickly, if ever. So, Sweden did a really great thing... 👍👍👍

[@skaileep]

@@michiv334 , zanim napiszesz głupoty, zaprojektuj i zbuduj elektrownię jądrową. opanuj technologię wydobycia, przetwarzania i wzbogacania uranu. w międzyczasie Twój poziom rozwoju technologii, słodki przyjacielu, polega na wytwarzaniu energii z drewna opałowego i obornika osła. dlatego okazuj szacunek Radzieckim inżynierom i budowniczym.

[@teracyasu897]

And this was just less than 3 months after the PM was assassinated (Olof Palme) such a traumatic year for Sweden

[@casedistorted]

sweden always doing the best

[@VonSchpam]

8:12 With the press of a single button, Anatoly Dyatlov had solved the entirety of Russia's energy needs for 8 whole seconds .

[@Viso2K]

wow

[@gregory_fnaf_oficial]

Bro solved the whole eastern Block

[@kjp.7714]

If only we could do that today, One building for the entire half of Russia seems good to me.

[@gabrielv.4358]

Lol....

[@angelpalazzolo1660]

He got russia like a million energy for 8 but the energy wanted to escape not to be used so well it hapened

[@wholesomesandwich2437]

how ironic, chernobyl exploded because of a safety test and pressing the emergency shutdown button

[@amark4663]

@@ifuoo dang I did not know this thanks man

[@amark4663]

@@ifuoo we shall change it to self destruct button

[@joecostello1624]

Does that mean that we don't have a process to shut down a nuclear reaction fully yet or at least not one that they have yet to disclose what the public? Because if so why the hell are we even fucking around with something we don't understand. The genius of humans

[@vasyan123]

This is why you test before going to production.

[@juaquimgustavo4712]

@@ifuoo If you want i can tell the real hsiotry about that reactor,, and you will be suprised i worked there, nothing you especulate here is true.

[@rocket2739]

When you complete the five year plan energy production in less than 15 seconds. Smart move

[@williampittam1]

Smashing good fun for everyone

[@luissantiago4395]

True communism archived

[@layzee3810]

Everyone’s lightbulbs that night must’ve like fucking exploded or something

[@yutiros5174]

@@layzee3810 no since the electrical power output never reached more than normal. the energy they're talking about is the thermal energy coming out of the core. also, i'm pretty sure since it was during a test it wasn't actually connected to the main power grid. so no, no lightbulbs where harmed during the event (except maybe those in the reactor room).

[@layzee3810]

@@yutiros5174 interesting, thanks for the information

[@erikhendrickson59]

The amount of energy required to send the two MILLION pound reactor lid 100' in the air is absolutely terrifying!

[@moparman0314]

What’s even more incredible is that he said it was 2000 tons. If that’s accurate, it’s actually 4 million lbs US or could be almost 4.5 millions US pounds if it was meany as 2000 Metric tons. Either way, scary as hell.

[@MrKotBonifacy]

@@moparman0314 I guess metric tons. In Europe and (back then) USSR it was (and still is) metric system through and through, bar UK. Thus a tonne is always 1000 kg, or 2205 lbs (US).

[@Li.Siyuan]

@@MrKotBonifacy It was 2,000 metric tonnes. I worked on a safety upgrade in the Leningrad NPP in 1997, have seen these things close up and they're scary beyond belief!

[@MrKotBonifacy]

@@Li.Siyuan Thanks for the info/ confirmation. Cheers!

[@Li.Siyuan]

@@MrKotBonifacy 🖖

[@brianmuhlingBUM]

"This is like a car motor increasing power to encounter a jambed hand brake." What a great explanation! This is a great short explanation of the Chernobyl Disaster.

[@AnotherWS6]

No no, he said a car motor increasing PAST FULL THROTTLE......lol

[@iananderson8363]

The transitions from the the animation to the real reactor were amazing.

[@JiTiAr35]

"It's cheaper" Comrade Legasov

[@TeddyKrimsony]

it's what poor nations can afford

[@thomaskositzki9424]

@@TeddyKrimsony The Soviet Union wasn't exactly poor. Here is the point: Their economy was smaller than that of the NATO nations. To stay competetive in the arms race with NATO, they had to pour an unhealthy dose of their GDP into their miltary (just like the US in the last 20 years...). That led to other sectors of the Soviet society to be critically underfunded by the 80's. The rest is history.

[@dmitryhetman1509]

@@thomaskositzki9424 Yes, it was shitload of money for nucklear and submarine program. Point is if you can't afford it don't do it. And quality was always questionable

[@sta1nless]

@@dmitryhetman1509 They couldn't affort it but they couldn't stop either. Lagging behind NATO was surrendering, as they would've exploited any weakness.

[@dmitryhetman1509]

@@sta1nless They lose anyway, ussr is not existing country, and Russia will be soon.

[@jerryumfress9030]

I worked for GE back in the 1980s. We were working at a nuclear power plant in Arkansas when our electrical supervisor called us altogether to meet in the electrical shop. Quietly in hushed tones he explained to us that Chernobyl had just exploded. We couldn't believe it. We thought about all those engineers, mechanics, operators, health physics personnel had been killed instantly and that more would die later on. To us it was a tragedy way beyond what anyone could imagine. Some of us began to pray for those workers and their families, that somehow God would offer comfort. I've never forgotten that terrible day

[@humanbeing2420]

Only a handful of people were killed instantly by the explosion itself. The other deaths resulted from radiation poisoning as a consequence of the explosion, but those all took place some time afterward.

[@OMGtheEbolaVirus]

Arrogance takes a heavy toll.

[@razorbackroar]

i’m from arkansas lol

[@rudolphguarnacci197]

​@@razorbackroar Hilarious

[@Ansset0]

Don't mix "god" with physics

[@tinman7065]

What is sad is that the engineers who built and operated the reactor were not stupid. They were, as most nuclear engineers generally are, brilliant people. The problem is that in a totalitarian regime such as the Soviet Union, bureaucracy and politics often overrule sound engineering. The saying, "When science meets politics, politics always wins", might apply here. A lot of group-think, a system that discouraged anyone speaking up, and pressure to just make things work resulted in a disaster that cost many brave men and women their lives. Thankfully the lessons learned have led to improvements around the world.

[@genericscottishchannel1603]

I think it should be "When science meets politics, people fucking die"

[@iammekanic9800]

Hey kind of like Covid. Fauci was covids dyatlov.

[@imrankaixa]

@@genericscottishchannel1603 much better hahaha

[@orbator]

A french writer said: Communism is the art to turn brillants peoples seems stupids. Nazism is the art where dumbs peoples believes they are brillants.

[@Chopper153]

Politicians didn't allow the design engineers to let the operation guys know about the deficiency. Everything is supposed to be perfect in communist countries.

[@mod_123]

amazingly explained amazingly presented amazingly narrated amazingly animated

[@demarcuscousinsthe65th]

You forgot amazingly accurate

[@weasle2904]

One thing he got wrong was he kept saying modern reactors use "water" when Chernobyl also used water lol. I'm pretty sure he means heavy water, which is water that contains deuterium and acts as a moderator instead of a absorber.

[@SenkaBandit]

@@weasle2904 water as used as a moderator

[@weasle2904]

@@SenkaBandit Chernobyl used water, modern reactors use heavy water.

[@SenkaBandit]

@@weasle2904 Chernobyl used graphite as a moderator. Modern US reactors use heavy water as a moderator. Chernobyl only used water as coolant

[@mikaelandersson4733]

This is probably the best and most interesting video I've even seen on the Chernobyl accident. The focus on the reactor physics among with the 3D models made all the difference compared to other videos mostly focusing on the consequences. I've shared the link to this video to a large Facebook group with focus on nuclear energy, hope this gives you many more views. Greetings from a NPP worker in Sweden :)

[@Mike-Bell]

Thanks so much Mikael. I am glad my effort is appreciated and thanks for sharing. Views are mushrooming all the time.

[@terbentur2943]

This is the first video where I actually understood what was going on.

[@Mike-Bell]

@@terbentur2943 I'm so glad. I make particular effort to not go overboard too Sciency and the technical terms. And yet make it easy to grasp some quite complex physics.

[@Mike-Bell]

@Mikael Andersson for interest. The views linked with FB around the time of your comment are around 460. Total FB linked view are now 1,100 !!

[@mikaelandersson4733]

@@Mike-Bell Yup, I did what I could along with your other fans. Great work must be given credit :)

[@seemorebutts292]

"3.6 Roentgen. Not bad not terrible." Most underated statement in human history.

[@professorcow3671]

Not good not terrible

[@Coalgate_frsh]

Go to sleep at midnight: ✖️ Stay up till 2am watching a compilation of videos on chernobyl: ✔️

[@therustynut1081]

Night shift “ dude I bet you $20 I can kick flip the reactor lid”

[@carlmaster9690]

🤣🤣🤣🤣

[@calvinmaybe6550]

Heads or tails?

[@BenCos2018]

😂😂😂

[@maxonwolf5841]

@@calvinmaybe6550 it landed on its side… so… tails?

[@marianmarkovic5881]

I bet 20rubbels that it fall on head,...

[@JohnWilliams-fy1go]

Just breath taking, you answered my little questions like why the control room is scavenged up till today

[@Mike-Bell]

Glad you appreciated the effort. The scavenged control room is a cool story. However sometimes the truth spoils a good story. multiple comments tell me it was impossible for radiation stalkers to access the control room. Security was impossible. I would think it us safe to say the staff who would have had legit access would conceivably have pocketed a few keepsakes for themselves. I would have. 😅

[@Reza-sl4jm]

@@Mike-Bell those stuff will probably be end up in underground auctions one day, imagine if someone took the actual control room 4 az 5 switch, just imagine how much would it be sold for?🤔

[@LadyVineXIII]

@@Mike-Bell You fail to appreciate the ingenuity and stealth of humans. The sarcopagus was far from secure. Until that dome sent up, I can see a few determined souls braving both security and the radiation for that high value component.

[@datapoint6859]

I mean, I have several gauges and old switch gear from various dead industrial complexes littering my shed walls, but nothing that would register on a Geiger counter. Scientist, engineer or other, it doesn't seem like a winning move to salvage this site. Those who salvaged all the left over response vehicles/aircraft (that have not been cancered to death that is) would likely agree.

[@allahsnackbar9915]

seeing that massive system of pipes i can only imagine how many hours of plumbing alone went into the construction

[@martincorneille7998]

The best explanation I've seen so far. I would just add that what turned Chernobyl into a disaster unlike Three miles island was the absence of a confinement shield around the reactor

[@erikziak1249]

Let one thing be clear: The reactor did not behave in a way that was not known. It was known. But it was the policy of secrecy, suppressing information and general paranoia in the Soviet Union, that led to this disaster. The operators were highly skilled and professional. There was no "pressure" present (as depicted in the HBO series). They were cautious and confident in what they were doing. The problem is, they were not told the full story, the truth about the RBMK reactor and its design. Until the disaster at Chernobyl NPP, safety concerns were only from the viewpoint of how to protect workers from the radiation of the reactor. After Chernobyl, the safety shifted in how to protect the reactor from operator error. This was a very valuable lesson learned. The automatic reactor control and safety systems had to be manually disabled by operators at Chernobyl in order to do the test. They worked against the safety protocols and were aware of it. If they knew the full truth about how the reactor behaves in those conditions, they would have never ever do what they did. This was not the first time that this test went wrong. The Leningrad incident ten years before Chernobyl made this clear. Lucky for them, at Leningrad, they performed the test with a "fresh" reactor, which was not operated for extended periods of time. At Chernobyl, the fuel rods were burned up much more. The operational reactivity margin was way lower, which resulted in even more control rods to be withdrawn, making the reactor extremely unstable. The lesson learned from Chernobyl: Protect the reactor from human error. Today it is impossible to manually withdraw more control rods than is safe. Also design changes were made to the control rods, removing the graphite displacers with steel ones. The efficiency dropped a little and the fuel enrichment had to be raised a bit to compensate for that. I cannot stress this enough: The reactor did not fail. It was the human operators who failed. The design of the reactor was known to have certain issues and the designers knew of them. But the operators were not told the full truth. Even worse, after the incident at Leningrad NPP, where a similar test resulted in an almost identical result, the full truth about the reactor was not told to the operators. Human error and a paranoid mindset made the Chernobyl accident happen. The technology did not fail in any way. It was a human mistake and error. The lesson from Chernobyl is clear: If you do something, you must know at each point in time what you are doing and understand what, how and why works. If critical information is being kept from you, you inevitably make a mistake, sooner or later. All the natural laws are known and the reactor was designed properly. There was absolutely no miscalculation or misunderstanding in the laws of nature. There was just human error. The operators are not to blame. The whole culture is to blame, if it is poisoned by unnecessary secrecy and paranoia. Also, we need to protect delicate technology from humans the same way we protect humans (and the whole environment) from dangerous things like radiation, chemicals, etc.

[@Mike-Bell]

Thanks for a great explanation

[@JC-lu4se]

Finally! Someone who's read books on the event. The shady Ministry of Medium Machine Building designed the reactor, and kept all its dirty secrets to itself.

[@PeterbFree]

Indeed. Now stop voting for democrats and make the world safer 👍

[@MegaEmmanuel09]

@@PeterbFree ...what?

[@Lightningchase1973]

@@PeterbFree you want to say, vote for corrupt GOPs, to manage to perform such disaster at home?

[@Mike-Bell]

Corrections thanks to commenters: *The bottom control rods were not coupled with the AZ5. AZ5 only lowered the top rods. If the bottom rods had moved as animated the disaster would have been averted. Here is the corrected video in the Russian version of this video kzbin.info/www/bejne/hJa9hJZ6j6aSq7s *There was a smaller first explosion followed by the main explosion approximately 2.5 seconds later. See kzbin.info/www/bejne/hJa9hJZ6j6aSq7s *The delay meant less xenon because of the longer time to burn it off. *It is not certain whether Akimov or Toptunov pressed AZ5. In certain accounts Akimov disconnected the servos to drop the rods faster. *The lid weighed 1,000 ton *The return loop from the turbines is indicated here. kzbin.info/www/bejne/hJa9hJZ6j6aSq7s A3-5 is the Russian spelling for AZ-5...

[@lordvader6172]

This video was probably the best explanation for Chernobyl I've ever gotten. Thanks!

[@connclark2154]

missing a return pipe from the condenser to the reactor

[@Mike-Bell]

@@connclark2154 Yup true. The return pipes routes are not clear in the drawings I that I got my hands on so I didn't know how to model the return in the 3d's either.

[@Selmarya]

@@Mike-Bell the animation still way better than i can ever want to achieve

[@trd710]

@@Mike-Bell not a bad explanation however Anatoly Dyatlov did get interviewed, have you watched his interview? he provides so much information about what was going on in the control room from his 1st hand experience... and "nuclear stalkers" cant get close to the reactor plant to remove anything which is a relief because pripyat has been further destroyed by marauders... not to be confused with urbex guys who have rules by which they are to leave the place exactly how they found it. security within the exclusion zone is very tight due to marauders but there are plenty who take the chance to document and even try to maintain the place for future urbex. Some channels for you to see this would be Bad Cat, Shiey and Kreosan.

[@artisanrox]

I also want to comment how helpful the utterly seamless transitions from animation to the real thing were. Made everything so clear. Thanks for this educational experience of this horrific event.

[@teracyasu897]

I feel so sorry for the staff involved, it wasn't their fault since they didn't even know about the hidden danger, they paid with their lives trying to fix the problem and not even comprehending how bad it was.. may them rest in peace and hope they are at a better place than they were at the time

[@kommunistkomsomolskiy]

Don't worry. The culprits were found. The employees knew about the danger.

[@DynamicSeq]

WHAT???...they broke every safety rule....If they did't had pulled all of the control rods out, this would never happen.. They are 100% at fault...

[@BarbBaych]

​@@kommunistkomsomolskiy yea found dead

[@brucetucker4847]

They knew they were violating every safety regulation in the book. To go back to the car analogy, it's like speeding toward a group of pedestrians on a busy city street at 120mph counting on the fact that your ABS brakes will stop the car just in time when you jam the brake pedal to the metal. If the brakes fail at 120 mph but wouldn't have failed at 35 mph it's still the driver's fault - maybe he didn't know the brakes would fail in that particular way at 120mph, but any idiot knows not to drive down a busy city street at 120 mph.

[@pauldh62]

I thought two senior members of the team were given prison sentences. Did they die in jail.?

[@NealB123]

There were people at Chernobyl who made really bad decisions that, combined with design flaws in the reactor, lead to the disaster. But there were far more heroes present who limited the disaster to only the one reactor and prevented it from spreading to the other reactors. If the fires raging in the turbine hall had engulfed the other three reactors, much of Europe would be uninhabitable today.

[@cytrynowy_melon6604]

Europe being unhabitable is a myth, debunked many times. Soviet Union's propaganda tried to make people focus on heroism instead of the system flaws, so they kinda overblown the importance of heroic task.

[@n.c.pictures]

@@cytrynowy_melon6604 only reactor 4 melting down already affected a large part of Europe badly for years. Now imagine what would've happened if all the other reactors melted too.

[@tracklizard4018]

@@cytrynowy_melon6604 People are still dying due to the disaster in places like Germany, Spain, and Norway.

[@brentfarvors192]

@@cytrynowy_melon6604 No. It really hasn't been "debunked"; If only reactor 4 continued to burn unabated; YOU would be dealing with the fall out right now! You would be seeing %70 overall cancer rates, with %95 in the hotter zones. At least a %60 still born rate, with cancers developing quickly in "normal" births. Those brave men, literally saved the world from living in fall out bunkers on a permanent basis!

[@user-hp3hf9wr1y]

@@tracklizard4018 No

[@BBayjay]

Bruh remember us when you're famous. This shit is on point.

[@JC-lu4se]

Must you use "bruh"?

[@BBayjay]

@@JC-lu4se Must you be so miserable?

[@frankierzucekjr]

This was really fascinating, thank you for all the work you put into this. I always wondered what had really happened

[@MrKnoxguy101]

Hoping to achieve a better understanding, I’ve always wanted someone to make a video giving a visual reference as to what took place that night within the RBMK reactor when things went wrong, and you did this masterfully. Thank you.

[@tomr6955]

This really is the best explanation of the event. You should be very proud

[@Mike-Bell]

Thanks for the compliment Tom. Yup I am chuffed

[@dr.jamesolack8504]

Most thorough explanation of the Chernobyl incident I’ve ever come across. You guys deserve some kind of award for this exceptional, play by play description of one of the most serious nuclear disasters in history. Very well done Matt and Mike Bell. Bravo!!! Edit: Instant new sub here from Columbia, Missouri, USA 🇺🇸 And a big 👍 for everyone who played a part in this remarkable video!

[@Mike-Bell]

Awesome. Thanks for the subscribe 😊

[@ravingfurryforlife]

Love this video. Explains everything in a concise manner and I really love the 3D cutaway animations so we can get a sneak peek inside the reactor.

[@Danimal619]

Great video, the 3D tour was incredibly helpful, I've watched many videos on nuclear and Chernobyl specifically and the model here was by far the most comprehensive and informative.

[@palframan5]

This is one of the few accurate videos that explain the events of that night in simplistic terms without clouding the facts with 'untruths'. Good job Mike,

[@grimmig13]

I come back to Chernobyl documentaries and such every couple of years, kind of a tradition if you will, and I must say what You've done here is amazing! You've managed to tell the story and effectively explain what happened in 13 minutes, and still do it better than most 30-60 minute lectures and make it more clear visually than 45-90 minute documentaries. Bravo, good Sir!

[@zeusantony5027]

This is superb and sensibly narrated. This must be one of the 10% of the best on KZbin.

[@fapmashina1]

Best explanation of this catastrophy so far! Well done!

[@matrixfull]

I really like how clean your video message appears. It's so easy for me to get confused but not in your video. Was able to finally understood what and how exactly happened from start to finish.

[@Mike-Bell]

Glad it was helpful!

[@processofelimination8967]

“Man can dream up the most amazing things, but ultimately it’s humans responsible for the things going wrong” that sounds bad

[@jfbeam]

Indeed. There are no more dangerous words than "It can't do X". Titanic can't sink. The RBMK design can't explode. Etc.

[@Blueknight1960]

Humans will always be the weak link.

[@marianmarkovic5881]

well that is easily truth,.. someone desighned it, someone else builded it, and someone else mantain it and control it,... every accident had error on one or more of those stages,...

[@MackeyBigBoy4014]

@@jfbeam Another examples are planes can’t collapse the World Trade Center.

[@moparman0314]

Nice job on the video. The animations were well put together.

[@denvan3143]

An excellent presentation; thank you for producing this.

[@sega-nesmaximus6664]

This was amazing to watch! I’ve read up, and understand every part of why the reactor went into a meltdown phase, but your video was able to explain every detail, and every part of it all... in under 13 minutes!! That’s an amazing feat! Great job on this!

[@cyberfunk3793]

Well if you understand it, can you explain why lowering the graphite that is already in the reactor would increase reactivity? Water at the bottom is replaced by boron on top - net result surely is less reactivity, not more, and afaik the reactor is hottest at the top, not the bottom? The only thing that makes sense to me is this explanation if for some reason the reactor was really uneven, and even though net reactivity decreased, it increased locally so much in the bottom to cause the explosion. The other option would be that the rods were actually pulled out so far that the graphite was out of the reactor until the button was pressed.

[@chengaanimates2108]

@@cyberfunk3793 The graphite didn't reach all the way to the bottom of the reactor, so when it was lowered, it displaced the water at the bottom of the reactor, to the point where there was almost nothing controlling neutrons at the bottom of the reactor, which caused a localized power surge. This was explained in-video, by the way.

[@cyberfunk3793]

@@chengaanimates2108 "so when it was lowered, it displaced the water at the bottom of the reactor, to the point where there was almost nothing controlling neutrons at the bottom of the reactor, which caused a localized power surge" And this would have been compensated for by the water(or boron in the control rods) replacing the position higher up where the graphite had been before, so the net reactivity would have been less unless for some reason the reactor was functioning very unevenly and there was significantly more reactivity lower down, which would be strange as the temperature is higher the higher you go so it should be the opposite: more reaction higher up or at the center. "This was explained in-video, by the way." The explanation doesn't add up, as I made clear, by the way.

[@dave_in_florida]

I have heard that the heat was so intense at the bottom that things melted and control rods could not move down

[@kjamison5951]

Western Nuclear advice: “If in doubt, ask!” Soviet Nuclear advice: “If in doubt, you are delirious. Take this man to the infirmary!”

[@redsun9261]

yeah, ask the people who build nuclear power plant in Fukushima. It constantly leaking high amounts of VERY radioactive water into the ocean for a fucking 10 years. 4 reactors melted and 2 of them expolded.

[@brentfarvors192]

@@redsun9261 The problem with Fujushima being; They literally cant do anything to stop it...

[@redsun9261]

​@@brentfarvors192 They could have just build a seawall high enough like every other NPP on the ocean shore has. Tsunami was completly predictable, its not something that happens once in million years, yet coproration, just like soviets, ignored basic safety of construction.

[@brentfarvors192]

@@redsun9261 Oh, I definitely agree; They should have NEVER built the facility without sea walls; Still doesn't help now, since it's already melted through the core...They basically have a bunch of melted corium laying on the sea floor; Every time the tide comes in/out, it is taking the radioactive waste with it...

[@allahsnackbar9915]

@@brentfarvors192 just putting your plant by the shore and not by one of the inland lakes when you live right on top of a seam in two tectonic plates says enough for me lol

[@markmuldoon805]

Nicely done. The animations and modelling were excellent.

[@Rico-bj2gy]

Outstanding work and you’ve got a great presentation style. This is proper documentary standard and was a balanced and fair assessment

[@teKniQz]

This was the video I have been looking for, for years now! A well explained, detailed, animated account of what had happened. You put the perfect amount of technical information on how the RBMK reactors work, and how they’re flawed. Great job.

[@Mike-Bell]

I set out to achieve exactly what you describe. I'm glad you think so and the your comment is much appreciated.

[@RusskiBlusski]

As someone who has done a lot of reading and digging on what was going on in that reactor that night. This so by far the best video I have seen on the subject.

[@JH-rf2nm]

Subscribed for the extremely in-depth analysis and absolutely incredible visualizations.

[@keithnaylor1981]

The most perfectly narrated video I’ve ever seen, clear and unrushed. There’s lots of informative videos on KZbin which are ruined by people who rush through dialogue as if they have a train to catch! I will look through your listing for more gems.

[@mattbellza]

Stunning visuals and video!! Please post more!! I learned so much my friend

[@elmoelmerson172]

Wow, I didn’t expect to see this in my feed!

[@spoutnik511]

Merci pour les sous titres en Français ! Sa fait plaisir d'avoir un véritable documentaire de qualité.

[@nyom6378]

It's kind of terrifying to think about Khodemchuk after all these years. He was never found, we don't know if he's under all of that debris, if his body decomposed or anything, it's heartbreaking

[@lucianososa1637]

From what I know the radioactivity is high enough to not let decomposition causing bacteria and fungi live, so probably his body is only damaged by the debris and likely burns, considerably well preserved compared to most corpses.

[@kommunistkomsomolskiy]

His body evaporated. There are very high temperatures.

[@taraswertelecki3786]

I have no doubt he was vaporized in the explosion, and died instantly. He was more fortunate than the others who died a slow, agonizing death from Acute Radiation Syndrome.

[@janandrea]

This is spectacular animation, and really helped me visualize what happened. Thank you for all your hard work!

[@thexstreetfr8648]

I love it! Thank you so much for those animations, models and photo... I learnt that between the lid of the reactor and the reactor itself, there is a huge gap for control rods

[@leokimvideo]

There are still pieces of radioactive graphite in the far away surrounding area. The KZbinr Bionerd was good at digging them up. The poor cleanup of the area is to this day a disgrace.

[@pimmelberger9967]

Typical Russians

[@CheddarMannn]

It was not "poor" per say. It could've gone better, and it should've never happened, but a reminder that the cleanup had the budget exceeding that one of the ENTIRE Apollo space program, so it was surely one of the biggest endevours in the modern world

[@euvo_sound]

yeah and other ukrainian channels (one of them being kreosan) saw a intact graphite rod just sitting in the jupiter plant

[@21boxhead]

YOU DIDN'T SEE GRAPHITE YOU DIDN'T!!! BECAUSE IT'S NOT THERE

[@finariumtv8740]

@@euvo_sound Doesn't make much sense. The graphite would cool down extremely fast. Only the uranium fuel would keep pumping heat. And if it was ejected from the actual reactor it is unlikely to be concentrated enough to do so.

[@michaelm1]

This is a beautiful, accurate, informative and respectful video. Thank you so much!

[@TheFilwud]

Excellent explanation, without getting to deep into reactor physics, you did a grand job there!

[@LadyVineXIII]

Such a tragic loss of life. We have to commend the operators who sacrificed their lives to keep the other 4 reactors from suffering the same fate. Chernobyl was a huge disaster, but it could have been so much worse.

[@Manny.93]

Chernobyl only had 4 reactors at the time of the accident. But they were building unit 5 and 6 at the time who was never completed. The last reactor shut down early 2000

[@LadyVineXIII]

@@Manny.93 Ok, that's why I have heard of more than 4. I can understand why the other two were nixed.

[@Manny.93]

Haha yea. There are some videos on YT showing people visiting the locations of the new reactor buildings

[@stlawstlaw7585]

Layers of Iies promoted both by Soviets and the West. It was the biggest CIA operation in history.

[@CONTACTLIGHTTOMMY]

Nicely done. Excellent production values. Impressive editing. Appreciate the time and effort you put into this.

[@Mike-Bell]

Much appreciated!

[@mistakay9019]

it's 2022, I've seen a few documentaries and the obvious series but out of all of them, this video was the best at explaining what happened clearly. Cheers bud.

[@mattb7156]

This is brilliant. You are very skilled at capturing detail of a complex subject. The animation is stunning, and your narration is perfect.

[@Mike-Bell]

Wow, thank you!

[@andrewrominger2537]

I watched your previous Chernobyl video, and this one is another amazing visualization and explaination. Definitely blows all mainstream media out of the water.

[@andyriley6254]

Prob the best 'laymen explanation' I've seen yet. Top work👍👍

[@Velossitee]

You make very good points, added detail to the scientific happenings within the reactor rather than just the design flaw being that "it was graphite tips" and gave in depth information such as what "xenon poisoning" is. I never knew this before, there wasn't enough information on youtube at least for this particular thing.

[@jakewallwork2280]

I just have to say, incredible work! The animations, the attention to detail, the 3d rendering, the information served. By far the most informative and polished animated info-videos I've seen! Fantastic work 👍🏻

[@vegassims7]

Well done... I just started watching the HBO drama and wanted more info. Great timing.

[@josephfrechette9916]

Your in shock. Go to the infirmary.

[@lastof4brothers]

Very indepth explanation for all the nuclear jargons I've been reading and watching. Thanks.

[@daisiesandazaleas]

Thanks for the video! It actually made so much sense to me and I’ve watched 4 other videos which left me confused. This one really helped me understand

[@KanamixOtoah]

I've watched several videos about this, yours is the first that actually gives a decent visual and explanation for what exactly happened! Thank you!

[@audettere]

This is 100% quality

[@chakraborty1989]

AZ 5, a button that killed Soviet union too.

[@matthewjdouglas6471]

Really amazing the way you have demonstrated what went wrong that awful night.

[@Delta2D2]

The most simplistic, well visualised & explained timeline of events. Very well done. I was one of 22 people in the UK who developed an illness that is categorised as ‘most likely’ attributed to the fall out from Chernobyl. The ‘most likely’ title means that the government doesn’t need to pay compensation, though my Doctors over the years since 86 have all agreed on radiation poisoning. Nothing like being in the Wrong place, at the Wrong time‼️☢️

[@765kvline]

One of the best documentaries on the actual process of the reaction and explosion.

[@gurditpanesar]

I’ve watched many of these. This is by far the best one. 👏🏼

[@tonkmann]

This video honestly helped me with a history project because it's so detailed and awesome!

[@BaHeK83]

Excellent explanation! So short and so understandable. Without useless emotions and, finally, more positive then negative ending

[@bjoernphotography]

Really good - keep on going with such good videos!

[@casedistorted]

This was very well done, and all the information I could ever want in a very well made animation. This is S+ Tier.

[@wilhelmbittrich88]

This was a GREAT video! I've read a lot about the Chenobyl disaster, but the way this video explained it well with a combination of visuals that really makes you understand it a lot better. You've earned another subscriber.

[@TwoFourCharlie007]

This is the best and easiest explanation I’ve seen so far, great video, Thank you, very informative

[@Mike-Bell]

Awesome, thank you!

[@user-bj7rn1zb3j]

Спасибо за адекватную оценку произошедшего, грамотное объяснение физики реактора, а так же за отличную анимацию!

[@pablobejeranor.2345]

Great job and investigation, stunning RBMK video and 3D model 👍👍👍👍👍

[@fonz-su6xb]

You are so well spoken and easy to understand..perfect video!

[@MrJokkoma]

You should take on more disasters that has happened in the past, best animation so far and I appreciate that you talk calm and collected.

[@SOFTWAREMASTER]

Really well made vid. And animation is out of the world man.. Nice one..

[@renemonnier3286]

Thank you for this very clear and concise presentation !

[@drewhartman6462]

Very good visuals. Very well done.

[@patentlyrubbish]

I think you're right to remind that this was designed in an earlier time, without much of the detailed knowledge and modelling that we now have, and that it is easy to criticise individuals who did not have the benefit of our hindsight. However, that said, it's pretty reasonable to criticise a system that allowed the reactor to start work before its safety testing was complete, placed very clear pressure on its engineers to complete the test regardless of whether the moment was suitable or not, and decided not to tell them about known flaws in its emergency shutdown systems. Just as this was a steam and gas explosion not a nuclear one, the root problem was a managerial failure not a technical one.

[@vidgamarr5126]

Human Incompetence. The source of 99.8% of the world’s problems.

[@taraswertelecki9886]

@Amy Weinholtz The U.S. also has done its share in that regard, and then some. And we also had nuclear accidents that have killed people horribly by radiation poisoning and acute radiation sickness.

[@pietrucciosoraperra4377]

Perfect. The best explanation I've ever found

[@Mike-Bell]

Glad it helped!

[@bass_lander]

Very interesting, good explanotary graphics. Thank you.

[@skyler9988]

8:42 will always give me the chills because, power was off the charts, and that delivery of "there wasn't anything left to do the measuring," like something tiny observing our side of things, and we show it our normal vs its normal, and the size between the two things is overwhelming

[@jimfrazier8611]

Another cause of the instability that rarely gets mentioned was bulk cavitation in the main coolant circulating pumps. They had double the number of pumps running than the test called for, which combined with the turbines only drawing enough steam to supply internal plant loads, meant that very little heat was being removed from the coolant in the steam separator drums. This water returning to the pump suctions was still on the verge of boiling, so the low pressure at the pump impeller inlet was actually casing the coolant to boil in the pumps, resulting in large flow instabilities in the core. This was a known issue with the RBMK reactor design, which is why low-power operation was generally avoided. One other aspect of Xenon-135 poisoning is that there are two ways to get rid of it, either by giving it time to decay or by feeding it neutrons. The rising power due to void formation in the coolant channels stripped much of the built-up Xenon from the core, casing another rise in reactivity.

[@Mike-Bell]

Thanks for this and explained so well. It is important info and does make a lot of sense as a key contributor and included in INSAG-7 but more difficult to understand in the dry technical wording. The feeding of neutrons to xenon also is very useful. And scary that it happens that fast. A disaster must have many factors in the disaster chain and cavitation is a big one for Chernobyl. Whilst making this I was cautious to not go too far down the technical detail rabbit hole because the vast majority of KZbin viewers are primarily here for the entertainment value or so I thought. I am pleasantly surprised by the response so far which shows there is a large appetite for meaty technical videos because that is my interest and strength. It is quite striking that the current age viewer profile for this video is 35-44 which is a lot older than usual KZbin audience. This means I can do more depth on technical but striving to illustrating complex workings in an easily understandable and visual manner.

[@erikziak1249]

@@Mike-Bell You can give simple answers to complex questions only to a point, beyond which they become meaningless and simply wrong. It is a delicate balancing act on the edge of a knife trying to avoid technical terms and details and still paint an accurate and understandable picture. Your video is really good, in spite of some minor details which most people will not notice. I am also surprised, in a positive way, by the comments section. I did read also a hypothesis that the reactor became promptly critical with fast neutrons before it exploded, as the neutron flux spiked dramatically, so the effective cross section and the physical layout of the reactor core made it theoretically a fast reactor. This is just pure speculation based on mathematical models. Of course, there was no nuclear explosion.

[@jimfrazier8104]

@@erikziak1249 Prompt Criticality does not occur with fast neutrons, it occurs with prompt neutrons, which are released almost instantaneously at fission. Each U-235 atom releases on average 2.43 neutrons per fission. About 97% of those neutrons are released instantaneously, while the remaining 3% are delayed by up to a few seconds. This slows the overall fission cycle considerably, providing much needed stability in the core. However, once you get enough positive reactivity that the reactor power can increase with only the prompt neutrons, you get a slight power increase every cycle, but you now get those minor increases 100 trillion times a second. The delayed neutrons will still add positive reactivity, but by that point the power is so high they almost no longer matter, and chunks of graphite are strewn around the parking lot. Or, if it occurs in a water-moderated reactor, you might find yourself pinned to the roof by a control rod. Yes, that actually happened in 1961, at the SL-1 prototype reactor in Idaho.

[@erikziak1249]

@@jimfrazier8104 Thank you for correcting my wrong assumption. It was a couple of years since I was "into this". Maybe I got some things wrong or do not remember them correctly anymore.

[@jimfrazier8611]

@@Mike-Bell admittedly I'm not the casual viewer, as I was operating nuclear reactors for a living when Chernobyl happened. To be fair though, when my submarine pulled into port and I was able to access the world once again, I was far more concerned about my girlfriend dumping me than I was about the Russians causing the worst nuclear disaster in history. #Perspective

[@nicholaskelly6375]

An excellent video. The designers of the RBMK were well aware of the problems of the design. Particularly at low power levels. Apparently they produced a detailed manual explaining what the operators should do. However the KGB felt that the manual could fall into the hands of a terrorist/saboteur. As a result the manual was suppressed. As a result of this the power station staff had no real idea of what to do. The remarkable thing is not that the disaster happened but that it hadn't happened earlier. As you point there had been problems at Ingalina and Leningrad. But due to the culture of paranoia in USSR this information was not disclosed.

[@Mike-Bell]

Fabulous comment!! Thanks. I'm learning all the time from your comment and others like it...

[@cytrynowy_melon6604]

Are there any sources for claim that KGB was behind preventing releasing manual about reactor flaws, though? Because there are sources that main designer of the reactor Nikolay Dollezhall ignored the reports of flaws, as acknowledging them could hurt his career, because he was seen as a flawless genius in USSR. Alexandrov who was supervising him, was also engaged in advocating and supporting this reactor type. It is true that moving the supervision of operations of nuclear power plants from one ministry to other apparently contributed to problems with communication and flow of information. But this transfer was done because designers of reactors most probably lied that those are ready, very safe much more than they really were, so party assumed that they can be supervised by more 'civilian' ministeries, such as ministry of energy. In my opinion designers were too ambitious and lied about progress with reactors, because of that they later had to rush the design process, with resulted with trivial errors. For example water space at the bottom of control rods resulted from miscalculation, designers initially thought rods could be longer, this space at the bottom of reactor was meant to be taken by longer graphite tips. When it turned out that those would not fit, and it is impossible to change the whole construction (as first reactors were build almost at the time of design process and equipment was manufactured already), they assumed they would use different technology to reduce amount of water (water film cooling). But this technology finally turned out to be unready, so they were left with too short tips. Like an architect who forgot to include the height of the building when planning number of floors. Absurd and terryfying. Buy that's what happens when design process is really rushed, that's why nuclear phycists shouldn't lie about having their reactor designs proven and ready, as this most probably happened. They believed too much in their own genius, especially because people from communist party, even such high ranking as Kruschev were not intelligent and knowledgeable enough to know that physicists are lying to them about reactor progess. Designers and other people from Kurchatov institute who were promoting the RBMK construction, such as Alexandrov, Dollezhall, Legasov (as he was not such a good guy in reality, earlier he was also promoting RBMK despite it's flaws) believed they can get away with such lies and errors because they are smarter than everybody else, and that ultimately nothing will happen, so errors in reactors can be covered up to protect their careers, especially because it was easy to keep things secret in nuclear industry in the USSR, which makes it even easier to designer of reactor to hide his errors. But it happened and revealed everything. If we only knew more about design process of reactor,. I think what happened and what really caused chernobyl, is what I have described above. Not screaming diatlov, but lying physicists from Kurchatov institute, such as Legasov. Ironically, HBO series end when he is talking about lies being the cause of all problems. He was a a part of that lie, despite show portraying him in good light in opposition to others.

[@nicholaskelly6375]

@@cytrynowy_melon6604 Quite Tomasz. It is easy to forget that the RMBK was a dual purpose reactor. As it was designed to generate electricity/district heating and to provide weapons grade plutonium. Actually it was carefully designed to allow it to operate on natural uranium without using heavy water. What is apparent is that the lead design engineer Nikolay Dollezhal (1899-2000) was well aware of its shortcomings. However for the reasons that you outline he kept quiet. That said the RMBK proved to be both reliable and robust in service. The issue with the fuel rods was understood by the Kurchatov Institute. Hence the manual to deal with this and the other issues of the reactor (At this point it is worth noting that all types of Reactor have their own operating systems, characteristics and foibles etc etc) From what I have read N.Dollezhal never actually claimed that he was "infallible" it was the Soviet media that did that. Let's be honest about this He was not the only scientist or engineer in the USSR who treated in this way. One thinks of Sergei Korolov for example! Or indeed Andrei Sakharov that is until he began to denounce the Soviet system. It was Valery Legusov The First Deputy Director of Kurchatov Institute of Atomic Energy (He would later commit suicide in 1988 apparently due to his despair over the Soviet civilian nuclear energy programme). Who led the investigation into the Chernobyl disaster. He made it clear that the KGB had suppressed the RMBK operation manual for the reasons stated earlier in his report to the IAEA. He was also extremely critical of the lack of a coordinated approach by the various regulatory bodies in the USSR to share information on the operating characteristics of the RMBK reactor. It is also clear that had the problems experienced at both Ingalina and Leningrad been reported accurately and disseminated to the correct authorities at the other nuclear power stations using RMBK reactors then it is almost certain that the Chernobyl disaster would never have happened. You are absolutely correct in thinking that the endless changes in top level management and the changes of ministerial control of the civilian nuclear programme was a major factor in this. Even Leonid Brezhnev was critical of the endless "reforms" to Soviet industry and privately is said to stated "Reforms , Reforms! People ought to work better, that's the problem!" Another issue that didn't help was the "Campaign" attitude to getting things done! As this often meant that things were done quickly and with very little concern shown to "difficult" or "troublesome" issues or situations. Which were simply brushed aside.

[@PORRRIDGE_GUN]

@@nicholaskelly6375 Were reforms and campaigns a legacy of Stalin's 5 year plans or Mao's great leap forwards?

[@mdepfl]

@@cytrynowy_melon6604 Everything I’ve ever read about short rods attributes them to equalizing the reaction - an intentional design versus a screw-up. Yours is the first I’ve read otherwise. What have I read? Internet drivel but lots of it. You sound quite knowledgeable - how did you find this out?

[@paulstone472]

Thank you. This is the first direct, no-nonsense explanation I've seen on what happened at Chernobyl.

[@Mike-Bell]

Thank you. I appreciate your comment.

[@debbiekerr3989]

I found this video truly amazing, and your use of colour diagrams makes it much easier to understand the reactor. The other videos I've seen only use line drawings.

[@igorzherebiatev5751]

Only one thing I have to add to this excellent video. At the time of disaster instructions were different and allowed operations with only 7 to 15 equal rods. 26 appeared only in 1987. Dyatlov in his memoirs mentioned that.

[@chrisrhodes5464]

I was in highschool when this happened really didn't understand how serious it was but I have learned over the years

[@brentfarvors192]

I was in elementary school; I knew how bad it was...

[@eversunnyguy]

Brilliant explanation. Great background score...

[@BackyardBeeKeepingNuevo]

Great video. The animation makes this subject easy to understand. Thank you.