Half Lives: Leonid Toptunov, The Man Who Blew Up Chernobyl?
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- เผยแพร่เมื่อ 22 มิ.ย. 2023
- Half Lives is a series dedicated to telling the stories of the people who were involved in history's nuclear accidents, from their birth, to the mishap, and their life following. These lives are often mixed up with lies, rumors and controversies. This is their true story.
Leonid Toptunov was the Senior Reactor Control Engineer (SIUR) for Unit Four on the fifth shift, the shift that oversaw the turbine rundown ultimately leading to the destruction of Unit Four. Unbeknownst to many, it was in fact Toptunov who pressed the infamous AZ-5 button that night.
But how, at just twenty-five-years-old, did he reach such a position, and how was his life ultimately stolen by his own sacrifice? Is Toptunov ultimately guilty for the explosion as many believe? This video examines his story from beginning to end and more, to determine whether or not this guilt is warranted.
I hope you enjoy the video.
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According to his father, when Leonid Toptunov was a child, one of his babysitters was Yuri Gagarin, renowned to be "the first man in space." Gagarin piloted the history-making Vostok 1 rocket. At the time of that launch, Toptunov was only 7 months old and attended the rocket launch with his father, as spectators.
Wow!!! Could u imagine?! ❤👍
Seems like he got to where he did by good old nepotism, no doubt his father greased the wheels so to speak. This was common in the soviet union. A bottle of wine or box of chocolates gets you an early visit to the doctor, and a good last name can get you everything else
This poor kid gave his life fighting this tragedy and it's absolutely disgusting that the Soviet Union blamed him for so long
Typical Soviet Union
If you think this aspect is bad, you really should read up on what the Soviet government did in the aftermath of the disaster.
@@martcon6757 oh I'm well aware of what they did for the cleanup process and everything and frankly it's disgusting the Patriot of human beings like that and what's worse they cut Corners resulting in a disaster and then blame other people for
@@rockytucker7480that's just Russia, err The Soviet Union for ya.
Maintaining the power of the establishment is more important than any one life... or a few thousand for that matter,
@@user-zb9lv3gh8s oh really so you don't think that they could have gained some points for Russia and passions the people that died tell him the truth so the world can prepare I think they would have been much more commended has a ton of the proper diplomatic way instead of lying to the world
why is everyone blaming the operators when A: the reactor design was pretty much garbage and B: the test they where scheduled to run is actually suposed to happen BEFORE the reactor goes online.
INSAG-1. ¯\_(ツ)_/¯
If it had been done when the reactor first came online, a disaster of this magnitude would not have happened. Fresh fuel is not as radioactive as it has not had enough time for fission products to accumulate inside the fuel rods. So even if it were to fail, it would not release this level of radiation. If I'm correct, the fuel in Chernobyl reactor 4 at the time of the explosion was nearing the end of its life, making it the worst possible moment for it to blow up, as fission products like Cesium and Iodine were at their peak levels.
@@Igor-ze8fr actually the test is suposed to be done before the reactor enters the grid for that exact reason as well as to avoid powerspikes.
The safety test was supposed to be done under completely different conditions. The reactor had to have been online or ready to go online (75% power). The reason being that there would be no Xenon present if the reactor was run at that level. In a nuclear reaction the Xenon acts to reduce or even stop the reaction, which actually happened. Just like dumping CO2 onto an actual fire.
The tendency to form xenon and the uneven 'hot-spots' (positive void co-efficient) were defects in the design of the RBMK type. Then there is the matter of the graphite tips to the control rods. That they could cause a power-surge was known about but kept secret after it happened at Ignalina NPP.
Toptunov & Akimov were powerless against the senior man, Dyatlov
@@NJPurling2 mistakes:
Leningrad and Chernobyl NPPs not Ignalina. And also the myth of Dyatlov, Dyatlov didnt order for the power to be raised, because he wasnt in the cr when the power dropped to its lowest point at 0:28. Also he wasnt the villain.
Leonid followed the instructions which were given to him.
I feel so sorry for this young man, it was not his fault.
Rest in peace Leonid Toptunov
Yes it was. He made terrible errors throughout. He seemed not to understand how the reactor worked. He disregarded basic safety regulations.
@@harrynking777- Keep in mind the level of secrets the U.S.S.R. had in regards to RBMK reactors & a previous disaster that occurred years before. No one knew .... not even Dyatlov.
@@harrynking777 Really? Exactly what "basic safety regulations" did he "disregard?"
The problem with that is that he KNEW those instructions were unsafe.
He KNEW, because he knew that the instructions differed from the standard procedure for xenon poisoned reactor.
The large issue was Toptunov was not in power to do so, which is completely wrong. NOTHING, no national interests, no wars, no nothing can be allowed to interefere with running of nuclear reactor by the SOPs.
A reactor engineer MUST always be empowered to follow the rules, if God himself tells you to disregard you tell the God to go fuck himself with a cactus and follow the SOPs.
The ONLY reason to EVER do something that is not SOP is when you have a sutiation for which the book gives no guidance. That is scientifically called "being proper fucked" and then you must solve the problem using your own knowldge, applicable procedures and knowledge of all the relevant people you can reach.
@@harrynking777i suggest you dive some more into the soviet union lol. Those guys didnt have much choice, they were just following orders from Dyatlov, who wanted to push the test through for a promotion most likely.
Toptunov was only on the job for 4 months and wasnt even qualified to be a Senior. Dyatlov has been there for over 20 years before the accident. Dyatlov disregarded a lot of safety instructions, believing he had a working shutdown button, which also acted as a detonator in that particular condition of the core.
“25 year old estonian man find one easy trick to blow up a 60 year old empire, and local commissars hate him!”
Click the link now to find out his secret
"Estonian"? Are you US American or didn't you watch the video?
He was born in the Oblast Region, nowadays Ukraine - from a primarly russian Family. His Father *moved* to Estonia, to work there as a russian in their Rocket production. Idk why now everybody starts to act as there wouldn't have been Russians around.
@@DaroriDerEinzige What the hell does being "US American" have to do with the guy being Estonian? If someone mentions his dad is Estonian, or moved there, some people are going to mistake him for being Estonian just by nature of how frequently errors are made. "US American" god almighty that one made me laugh
@@rrai1999 US Americans often don't know how that works.
You know, the whole thing of "Coming from a country which is older than some stews in this world.".
Idk how you make the "mistake" otherwise occurs. Look at the name, that the name sound estonian to you?
Is "Ansgar" a latin sounding name for you?
3.6 roentgen, not great, not terrible.
This is so heartbreaking. What a sweet man, and it's so sad to think what happened. HE was so smart and could have done so much in the world with his life. I don't think he did what he did to cause any problems, he just followed directions. This is a beautiflul biography for this man, thank you for posting it.
His (alleged) reincarnation:
akimov and toptunov waded through knee deep radioactive cooling water trying to open cooling valves. they knew this was fatal but did it anyways.
They didn't know it was fatal. Multiple people had already entered that room previously, and none of them had come down as badly. Equally, half a dozen people would spend as much time in there as them, and they would all survive.
@@thatchernobylguy2915Well, I partially do agree. Given his affirmation, I think he meant that they were aware of the high, even potentially fatal risk.. being there for several hours (it was their own decision to stay down there and do whatever they can, maybe due to their sensation of guilt and responsibility), it was more than clear that it would be fatal by operating so long down there. In conclusion, yes, I do think that they knew… but they hoped and tried everything they could at that specific moment. Indeed, good men and a terrible loss.
@@MinecraftProfi007 It was up, not down. The valves were on floor +27 (27 metres above ground), under the steam separators. Nobody had any idea it would be fatal, and they spent less than 20 minutes in there. The people on the other side of the room all survived, and the third person with them, Nekhaev, had his legs amputated due to radiation damage.
@@thatchernobylguy2915 Let me say, I highly appreciate your rich knowledge about the disaster and enjoy every bit of your videos! It is such a treasure to hear those „new“ and rare details about each individual person! A huge bravo for that. Well, sorry if I got the location elevation wrong and thanks for correcting me. Hm, I thought Toptunov and Akimov stayed much longer there (portrayed by HBO or other articles I read on the internet), that´s why I was confused. Nevertheless, you are gold, keep going with that, you do not know how many people who are interested in this profound and historic event, do eventually profit and learn a lot of new things! Thumbs up!! David
@@thatchernobylguy2915they received a high dose from the room on +24 as well.
If you step on the brake and it punches the accelerator causing the car to run out of control, do you blame the driver? What’s worse was the fact that the flaw was known but covered up
Meanwhile the USSR officials were like: "And so what if the brake pedal causes the car to accelerate wildly? The operators should not have driven the car at any speed that won´t allow the car to stop on its own. Yes we didnt tell that to them, but they should have known. Fixing the pedal issue would force us to recall all the cars for modification, which would make us look like idiots, which we are but we will not ever confirm that publicly. Anyway, if you ever drive a car and find yourself in a position in which you need to use the brakes, you are a bad driver and you deserve to stand trial and likely be sent into prison."
I work for a major telecommunications company as a technical CC operator, and I remember, about a year and a half ago we had a really rough shift. It was around 12:30 PM. I was slowly getting ready for my next break at 1:00PM. I was on the line, trying to sort out some issues through the phone. I took a quick peek on the screen, which has shown 8 people waiting in the line. "When the 1:00 PM shift joins, they'll all be gone, and the 2:00PM shift will keep their numbers low, and it'll be smooth sailing until 4:00PM" - I thought. Then, maybe a minute later, I felt some tension in the air. I don't know how, perhaps my gut feeling or sixth sense knew that something is going to happen, and it has tried to warn me. I was still on the line with the same person, sorting out the same issue, yet I've peeked at the screen, and now the screen has shown that we have 28 people waiting on the line. "That's odd. We may have yet another local NAS or headend issue somewhere." - I've thought to myself. I returned my attention back to the caller, and some 10 seconds the line began to cut out. I looked around, and noticed that my colleagues in the room have experienced the same problem, and they were trying to deal with it one way or another. A quiet "What the actual f*ck?!" - has slipped out of my mouth. The screen, which shows the amount of people waiting for an operator was still open in front of me, and now it has shown 84 people waiting. I tried to talk to the person on the line, but I was unable to say anything after that, and my eyes opened wide. 3 seconds later, the line went dead, and the screen has shown 127 callers waiting on the line, before the software crashed.
For a few seconds, there was nothing, but complete silence, which is pretty unusual for a CC midday. Everyone looked at his or her screen in shock and disbelief. "Is this real, or am I dreaming?! I must be dreaming! This is entirely impossible! Wake the fuck up buddy!" - I said to myself, then I've pinched the arteries on my arm and my neck. When I've felt the pain, I realized that I'm not asleep, and this is not a dream. I've turned my attention to the problem, tried to reconnect to our main system, and when that failed two times, the backup system, to no avail. When I've logged out of my shift at 4:00PM, the systems were still inoperable. I was still thinking: "Have I f*cked something up? Have we f*cked something up? I don't think so. But if we didn't, then how the hell could this happen?"
It's not the same league, hell, it's not even a similar ball game, I know it very vell, but when I went home and gave the situation a second thought, I realized that Toptunov, Akimov, Dyatlov, Kirshenbaum, Kudryavtsev, Proskuryakov and all the other staff present in the control room of the reactor no.4 must've felt something similar on that night in 1986. Utter shock, and disbelief.
"It is possible to commit no mistakes and still lose." - Jean-Luc Picard
He did everything right. It wasn't his fault.
The Soviet system is what was responsible for this catastrophe
It wasn't Leonid's fault, the supervisor is to blame, the operators were doing what they were told.
It turned out in subsequent investigations that they were all lied to, by omission. The dangers were known, there had been a close call several years earlier but it was hushed up. Dyatlov maintained until his death that he had been lied to, and had the warnings been issued instead of ignored the disaster at Chernobyl would not have happened. Given everything we've learned since it's hard to disagree with his claims.
That was one of the two systemic issues. When you run a nuclear reactor and your superior tells you to comming known unsafe action. You refuse, and if they still insist you have them removed.
No shit Sherlock
@@michalsoukup1021easier said than done when your career and livelihood is at stake
@@AppleUploader that is why I called it a systemic issue
Long before the accident, the danger had been reported and was known. The designers were in the process of replacing the original design of the control rods with a newer design, which was in process in other units. After the accident, the rods were replaced in all other RBMK reactors, including those still operating (for a time) at Chernobyl. However, when investigators, later reading the computer printouts, discovered that all rods had been removed and the safety system manually bypassed, their feeling was this should never have been done. The spin-down test might have been aborted, since it was only to determine how long the feedwater pumps and/or control and instrumentation could be run by the turbine as its speed continued to decrease. This was not critical to everyday safe operation but rather only to characterize the scenario in case of grid loss. You will find the complete updated report (mentioned in this video) to be highly informative and interesting. This video says "cold" feedwater was being introduced. According to the report, the feedwater was about 99C which is normal, but this high temperature of the feedwater made a steam explosion even more likely. It should be noted that graphite-moderated reactors have stability issues and that core design is no longer used. Offering a vote of gratitude to the many brave souls who paid the ultimate price assisting with the recovery of the accident. Thank you for posting the video.
When I say cold feedwater, I mean it was below the temperature of the water circulating through the reactor, stalling the positive void coefficient and necessitating the withdrawal of more control rods, while placing the temperature of the water at the reactor inlet within 2 degrees of boiling as it recycled through the reactor.
When they pressed the AZ-5 button, even a small increase in reactivity was enough to produce enough energy to flash all the water in the bottom of the reactor to steam.
However, nothing they "bypassed" would have prevented the accident, and the operators were unaware that the operating reactivity margin had been violated.
Agreed! Your videos are both educational, and are setting the record straight. Thanks for your knowledge, study, and the no-hype, no-nonsense presentation, my favorite style!
There is no problem with graphite moderated reactors. The problem is dual-moderated reactors. The water is a moderator too, only a much poorer one. Graphite moderated, gas cooled reactors like pebble beds or prismatic HTGR is fine and can have very large negative temperature coefficients of reactivity. If the fuel heats up the moderator in which the fuel is embedded heats up and so does the TRISO fuel particles. This has two major effects; the spacing between the atoms in the fuel and moderator becomes larger, which means that neutrons zip through easier without being moderated. It also changes the neutron spectrum subtly because they are colliding with hotter atoms; this shifts the peak of the energy distribution of thermalized neutrons slightly away from a resonance peak in neutron absorption in U-235.
The extreme case of this phenomenon can be seen in TRIGA research reactors where both the size and unusual uranium zirconium deuteride fuel combine to cause monstrous negative temperature coefficients of reactivity. You can idle the reactor at 50 W; eject a control rod with compressed air; get a 20 ms pulse of several hundred MW and then immediately return to hundreds-of-watts territory without even reinserting the rod. They do this (pulsing) to be able to generate very high neutron flux for short periods of time for reasearch purposes without any particular cooling system; just an open pool of water.
They might not have known it was fatal, but I'm sure they knew it was bound to have very dire consequences
A couple of points to note. The "feedwater" was only piped to the separators and adding water to the system this way does not actually send cold water to the reactor. The source of "feedwater' is the de-aerator tank or DA tank and the tank i believe was next to room 714 on level +27. When these guys were up in room 714 they were likely opening the feedwater supply valves rather than doing anything with the separator. The flow pipe from the deaerator to separator had two heat exchangers in the line presumably heating the 167C feedwater stored in the deaerator to the temp in the separator. We can see this process occur in the strip chart at 1:20 am to 1:22 am. In that time, about 6300 gallons of feedwater is added to the separators increasing their levels but the time to re-achieve boiling is very short indicating the heaters were in the line and operating at the time. The deaerator had a potential capacity of 29,000 gallons, so whether it still had a lot of water in it after 1:22 am is a question. The 3 feedwater pumps were likely on level 6. This where I believe Akimov or Khodemchuck goes next to attempt to get more "feedwater" flow. The only way to get water directly to the reactor pressure tubes and bypassing the MCPs, was via the ECCS system which I think many components had been damaged in the explosion.
IMO They all knew AZ5 would give them a pressure bump and were reluctant to use it. Weighing the risk of a pressure bump at this time may be the reason why Akimov seemed to have the final say on when it (when he realized he could not handle the situation with cooling) was pushed but likely too late anyway. Ideally the ECCS would have been triggered before the AZ5, had it been operational.
@@thatchernobylguy2915
I watched an interview with a former RBMK operator, who presented an interesting theory regarding the AZ5 button. According to them, the AZ5 buttons operated in such a way, that they required to be held pressed down for the rods to descend. If one should stop pressing the button, the rods would stop at the level they were at. This was changed after the accident, by replacing the button with a turn switch( infact if you watch any chernobyl documentaries, you can see them using a switch for AZ5 post accident). He theorised that Toptunov might have released the button at some point during the shut down, which in turn made the power surge worse. Anyways, thought that was an interesting theory. If anyones interested, I coould try and see if I can find the interview.
Yes, this is AZ-5 double press theory. There's actually some physical evidence to support it, and I can tell you how finicky these buttons are from my own button of the same model. I do intend to create a video about this in the not too distant future, so feel free to stick around for it. :)
@@thatchernobylguy2915 I will be looking forward to it 🤓
@@thatchernobylguy2915please do! Would be interesting to watch
Depends on the design. Most sensible designs these days have big electromagnets holding uo the rids, so as soon as you scram the reactor said rods drop free, under gravity.
That would have been a sensible thing to do in this case too, but then... yah...
In any case, those rods happened to be quite slow-moving, so it stands to reason that if a poisoned reactor had just cleared the last of its xenon, as the criticality was evolving so qiickly, they really wouldn't have had a chance to shut it down at that point. Not with a minimum of 18 seconds for the rods to lower.
Scram or don't scram - that reactor was going critical without the proper cooling, so there could only ever be one outcome.
Interesting
If he did not press AZ5 Cheronbyl would have self destructed any way.
Indeed. As soon as the reactor went prompt critical it was too late.
It wouldn't have exploded though, just melted. The correct comment would be "If he had not pressed the AZ5 button someone else would have."
@@krashdit would’ve melted down, burned through the earth and hit the ground water and China Syndrome’d, which would’ve been way worse.
@@krashd Even the most optimistic scenario ended with the reactor going supercritical without pressing AZ-5. It just happened slightly later. The bomb was already ticking, when they reduced the flow inside the reactor and increased the void coefficient.The reactor was so large and ensuring even flow so difficult, that even when the Diesel generators produced power for the pumps, it was not ensured that they removed the steam voids faster than reactivity climbed and more voids are created. At one point or the other, you need to start inserting control rods, and when you insert the control rods to end the test and shut the reactor down...well, there is AZ-5 and you have no idea how bad the idea is to use it, because the KGB is hiding this information from you. Why should you insert them slowly?
3:17 His girlfriend was so pretty, reminds me of Princess Di from that angle, and she looked so happy by his side... for some reason this photo hit me harder than any other in this video. He had such a long life ahead of himself and the fact his mom is still grieving for him right now just kills me.
He deserved a better end.
I agree with all of this, but I can't say the same about "pretty" sorry, I guess not my type at all.
Ìf you squint,hang upside down and pissed out your brain then yes she is pretty.
She reminds me about the singer Rusja, a soviet Ukrainian popstar of the time.
@@andyfield6854 hey now, different looks for different folks, but your daddy or mommy or whatever you got should've taught you not to talk about women like that, damn weirdo.
@@AuditorMadness yes she has not a ‘canonic’ beauty. Looks a bit big nosed, but looks nice.
Glad to see another video so soon! It's very interesting to see all of those black and white pictures as you talk. Good job
Thanks. Hopefully I'll be able to get a few more videos out over summer, and hopefully it will be some colour photos and videos (and a bit less repetitive) next time.
Fascinating story, I feel terribly for Toptunov & his family. Clearly he was a diligent student & power plant technician & leader. He certainly had no idea that the reactor would be damaged during the test. I don’t know if the reactor (or any reactors) are instrumented for Xenon poisoning, but at that point, I’m not sure it would have mattered given the ridiculous dependency of the Soviet state on secrecy to maintain their legitimacy.
Good point about instrumentalisation of Xenon poisoning. It would be very useful if that could be done. I'm not sure if it could or can be done today.
3 mile island also had xenon poisoning before it was actually released into the air. Xenon-133 is very common poisoning in nuclear power plants, so these plants release small amounts. The amount released in 3 mile was about 20 million cures. Giving each citizen in the area 1.4 MREM. a body CT scan has 1000 MREM. 3 mile island would have been like chernobyl if the operators didn't realize the mistake and fix it and alert authority. Not a single person was hurt nor a building destroyed. But It will live on as one of americas nuclear disasters, which was fixed. We stopped building nuclear power plants for a out 3-4 years after 3 mile and stopped producing them after chernobyl. It's being reintroduced into some state governments as it's fairly safe if properly maintained. Funny enough, a study has been done showing fossil fuels, killing 1 in 5 people around the globe from pollution. The confirmed number of deaths for Chernoyble, Hiroshima, and 3 mile was 32 deaths. We know there are thousands more from radiation. But fossil fuel has more confirmed deaths.
I absolutely agree, first of all with that he musn't know, that the reactor would be damaged. Second tought, I was after if Xenon poisoning would be possible or not; at that time. It's very hard to tell by now, that what was going on inside there at that night. It ended definitely. We are 37 years ahead, and still not acknowledging anything about the events before, and after all up until now. It's so sad, how many depicted it to be a must have future massacre for those who "would - will" cause WWIII, and that how it doesn't act well now; We will not find those, who are able to cause it. I also believe that it was a series of events, what happened, eventually; step by step, and somehow, I couldn't tell all up until this day, I can't believe that someone's were this much of a craze, about natural radio wave infections. What could they really cause to us now, 37yrs later, from the time DUGA stopped transmission?! Also, the similarity is right to say forming between natural radio waves and radioactive particles, oh ok, and it does in the matter of living organisms. We see. That's photosynthesis. But, if anyone. "bombed" this, bombed for the sake of life, of the restarts of the larger transmitters and end the mass scyzophrenia what's had been caused by the last 37yrs, and will be if cosmic weather will stay the same. Someones may had tought of this. Certainly not the workers I believe. Also, ever since no one nowhere released any info, of the question. How the natural radio wave infections kill? How the both (nrw and radioactive particles) would kill? They have said, buy Stalker, and be it. Ok, but not a single tought of education went on anywhere about these. Simply, we can see people kill each other anywhere. WHAT is nowadays happening, none of those events were picted anywhere, that's been released ever since. Out of question. It's Happening. Bamm.
Leonid Fedorovych Toptunov is a hero of the Soviet Union, a hero of Ukraine, a hero of Europe and a hero of all life and civilisation until the end of time. He stayed at his post, and put the safety of the world above his own life, knowing EXACTLY how terrible the price would be for him. There is no worse way to die, than acute radiation sickness. In many cases is far worse than being burnt alive, because it takes a long time to die.
Given his background and his expertise, Leonid Fedorovych Toptunov was the ideal person to have in control of an RBMK reactor, with a secret and potentially catastrophic flaw. It is both AMAZING and DEEPLY SAD that he had the insight to have noticed that a design problem did exist.
Although authoritarian scapegoating was and is endemic within Soviet and former soviet workplaces, its roll within highly technical activities is especially problematic. Technocrats and bureaucrats gravitate to assigning blame rather than troubleshooting a problem or a dilemma. This problem is the root cause of many Soviet disasters, including the Nedelin catastrophe, the Kyshtym disaster, and the delayed rescue efforts after the Kursk submarine explosion.
This is not a unique problem within the former Soviet block. Clement Attlee’s capricious attitude on the British hydrogen bomb program was disgusting, as was Charles de Gaulle’s dismissal of localised public health risks of French nuclear tests in Africa and Polynesia… and where do you begin with the Americans? Probably the Runit dome on Bikini atoll leaking Plutonium.
Anatoly Dyatlov was responsible for triggering the Chernobyl explosions. But he never knew about the danger of the carbon tipped control rods. Dyatlov was an unpleasant man and ultimately a tragic figure, but given his personal history and his profession dedication, I highly doubt he would have treated reactor four so recklessly, he had known the emergency scram procedure was a time bomb waiting to happen. Indeed, in the best all possible worlds, no one could have predicted exactly what happened that night. The best we could hope for in retrospect, was for everyone in authority to treat the reactor with the respect it deserved. The power down test should have been cancelled, the moment the shut down was delayed by the unexpected power demand.
Authoritarian bullies and nuclear technology DO NOT MIX. Which is why the North Korean missile program is such a problem for the region.
What about me 😢
He wasn’t ready for that position unsupervised, obviously. At least he knew he wasn’t ready and tried to mitigate it, only to be denied multiple times. Great story!
I've never thought he was one to blame. He was most junior there, Akimov and Dyatlov were more experienced. And Dyatlov was the one in charge. He was the one who decided to continue with the test preparation after the sudden power drop. He was the one who should have been more than aware that he's attempting a test which had been unsuccesful several times before and that he is attempting it from non-ideal condition. He should have known that he had a xenon poisoned reactor with a positive void coefficient operated by an unexperienced senior operator who was not prepared for the test beforehand. He was the one who decided to disregard the conditions of the test and decided to do it on much lower power than recommended. He was one of the authors of the test, I think, maybe he thought he knew better than the rest, but alas, as the events proved, he didn't.
Dyatlov wasn't the villain he's been made out to be though. He maintained quite strongly until his death that he had been lied to by omission. It has emerged subsequently that a similar event almost occurred some years earlier at Ignalina and the dangers of the graphite tips were known, but it was hushed up lest it be perceived that the design was flawed. It turned out that Dyatlov was right the whole time.
@@woopimagpie He was not such a villain as in the HBO series, but still the shift under his supervision disregarded some regulation. It wasn't like he said that they did everything acording to the regulation. They didn't. They had no idea that the explosion was possible (no-one had at that time), but still, the safety culture in that plant was lacking.
It's a foregone conclusion that the lowest on the ladder will always get the blame.
Look at the Herald of Free Enterprise ship sinking. Was the Captain at fault? Were the owners and company CEO and shareholders to blame? No, of course not. A seaman, working with dangerous H&S operating procedures, was held to blame. Go figure. How come the guy earing a fraction of the wage of those being paid big bucks for carrying responsibility (allegedly) is the one who carries the can. 😢
@@obtuse1291the lowest on the ladder who's conveniently dead, you mean.
@@Eltanin25 "The safety culture" in the entire Soviet Union was lacking (and severely at that). And don't forget how they ALWAYS tried to hide all of the accidents, because "soviets don't make mistakes" and "the less you know the better you sleep"
Such a driven and ambitious individual. Absolutely tragic loss.
It is not about "driven and ambitious", adjectives which were more his superiors' characteristics; ambitious was the system. It is about the capabilities this young guy would have brought to fruition if he had got the right daytime job and the right information.
We even can't fully blame his superior, because night shifts tend to carry on and on, although the situation was deteriorating and getting too complex. It also looks like the other shifts pushed the burdensome plan to the next one and the next one, and left the night shift (which is the worst to do it) alone.
I’m amazed I’m only seeing this channel now. I love the obsessive attention to detail.
The disaster was already bound to happen even before Toptunov pressed the button, so it's wrong to say "he blew it up". To my knowledge there was no way to shut the reactor down at that point, or was there? Would be interesting to hear if there was.
The disaster was not already bound to happen, it required the utilisation of said button for it to happen. There is a big difference between a core melting and a core exploding, Three Mile Island Unit 2 did not bankrupt the US and pollute a continent.
I think it likely would have been possible to lower control rods one at a time. This would have inserted a little bit of reactivity at the bottom of the core when the graphite displacer started moving downwards, but then it would have quickly reduced. The reason I think this is that the AZ-5/SCRAM button wasn't pressed due to a power excursion; the power excursion happened after the button was pressed. This would have required knowledge that anything was a wrong in the first place. If you inserted a single control rod and the positive reactivity insertion by that single rod wasn't big enough to blow up the core single handedly, this would have allowed you to get the absorber fully seated into the core and given you more margin to get the next control rod in.
Again. They didn't really think anything was wrong. The graphite is not a graphite tip on the end of the rod. It is a 4.5 m long graphite piece connected with a telescopic 1.25 m rod to the absorber and it is seated centrally in the core. During normal shutdown the neutron distribution is even throughout the core so lowering the graphite section doesn't increase reactivity. The absorber starts coming in at the top of the reactor and immediately lowering reactivity. This means the net effect typically would have been to decrease reactivity. But this time, for fairly arcane reasons, it wasn't and the reactor instead blew up.
Yes, MCP's were well on their way to cavitating before the AZ-5 button was pressed. So far I noticed 2 mentions of this so far in witness interviews, and I think that is what was being suppressed. They did not want to look like fools having pump cavitation be the root cause of the incident. AZ-5 sounds better. If the ECCS deployed before the AZ-5 button was pressed, and before the MCP cavitated at 1:23:45 am, there could have been a chance to mitigate the severity of the incident. I think the blame was tailored around the AZ-5 button and other actions that were closer to the real root cause of the incident were discarded. This was to deflect blame away from Dyatlov. In Dyatlov interviews, he says he does not remember any questions or concerns when discussing the experiment. But then he also says he remembers discussion about pressing AZ-5 at the start of the experiment. So which one was it? I think there were heated discussion about this experiment and Dyatlov just overruled everyone's concerns. He then tried to blame the incident on the AZ-5 button since it was the one action Dyatlov was not responsible for.
HBOs Chernobyl really made Dyatlov look like a villain when in real life as he’s portrait here he doesn’t seem like that at all
At first I had the same impression about HBOs series, how could one man cause the death of so many. So after I listened to Dyatlov's actual interviews in 1991 and 1996 i think, I saw nothing there around remorse for sending Akimov around the contaminated plant. He still seemed like he was "sticking to his story" and seemed actually very adversarial to Akimov and Toptunov. He never said a nice thing about them. Now, I am back to thinking, Dyatlov was really a jerk of the first order, who is good enough at ensuring the truth does not get out so people feel sympathy for him. Dyatlov knew Akimov should have never get near that feedwater tank (de-aerator).
Loved the video, thank you!
Just for further clarification on the perspective of his dose.
1300 rem equals to 13 Sv (sieverts), 1 sievert is 1000 mSv (milisieverts), 1 mSv is 1000 uSv (microsieverts). normal background radiation is around 0.1 - 0.3 uSv/h (microsieverts an hour). He received 13,000,000 uSv in a very short time.
wait a moment: somewhat down there in the comments it is reported, that Dyatlow had previously received 100 rem at a shipbuilding plant in Komsomolsk-on-Amur; Toptunov was an amateur boxing youngster, with once a broken nose! Could it be, that besides having to work this complex task on a night shift, (which shouldn't be done at night) they both were suffering previous body damage(s) and/or brain damage(s)?, which could have affected their decision-making! Similar to old professional Boxers, who get Alzheimer's in their old age, most severe Alzheimers!
Remember Muhamed Ali, alias Cassius Clay! Aircraft pilots, who fail their health checks get grounded! (just for comparison), nuclear operators don't?
LET'S GOO my boy done another great video
Unfortunately, the RBMK reactor design was flawed, deeply cost driven, lacking in effective safeguards and any previous failures were hushed up, in effect causing a perfect storm waiting to decend on anyone involved. I work in nuclear safety in the UK, and the idea of a nuclear disaster the magnitiude of Chernobyl gives me literal sleepless nights.
Your video was one of the most concise and logical recognitions of what happened, even some of the most in depth ones on YT leave out the data which explains the causes, whereas you laid them out, so thank you.
"Leonid Toptunov blew up Chernobyl..."
"...but it wasn't his fault." 🤭
if AZ5 hadn't been pushed, would it still have exploded?
@@ThomasHaberkorn
1° If Toptunov didn't pressed AZ5, Chernobyl would self-destruct anyways
2° Akimov and Toptunov are innocent cause reactor project is a trash
3° Both followed correctly the instructions but the reactor was poisoned because the day shift had to stop the test
So don't judge him as "The man who caused the Chernobyl catastrophe" because the fail was on the reactor project.
@@ThomasHaberkorn If you went back with a time machine you could have easily shown them how to prevent the accident by not pushing AZ-5. But pushing AZ-5 was always the plan from the start, during the safety test. If they just walked away from the reactor, it is likely that AZ-5 would have triggered on its own.
@@MinSredMash thanks, nice to know
Great video as always!
Thank you so much.
Wow that's the only picture I've seen of Dyatlov on the job. Great video!
Great video! Thanks
dude this is a great video!
It needs to be added, that the conditions caused by the problems already set the reactor into an unsolvable state at around 0:30 according to some experts, and also if the automatic safety system would have initiated the shutdown, it would have exploded nevertheless. Also AZ-5 (as far as I understand) was routinely used to switch off the reactor, no matter who were there would have pushed the button.
I get the feeling AZ5 was routinely used but it was also know that it would produce a pressure bump. Are there any report findings to that effect of how frequently AZ5 was pushed?
I can't imagine having that type of responsibility at such a young age. I can't imagine how terrified these men were that night. I never thought it was only his fault with the disaster.
The issue with Chernobyl was the lack of transparency within the USSR’s upper management, as well as Dyatlov’s ignorance. I don’t think there’s really much to unpack. If the reactor was designed with safety in mind, the disaster wouldn’t have happened, and the same can be said of Dyatlov making the decision to cancel the test.
Right on. Thanks for sharing.
I received excess of 5000 rads during my cancer treatments, it was over 6 months, twice a day. It left severe burns from it. Getting a full body dose of 1000 rads over just a few minutes I can only imagine how painful that would be.
I don't know how strong my dosage was during my radiation treatment, but by the end, I had nausea and diarrhea at the same time. Even without the burns, it is a miserable experience.
Dude what?!
5000 rad are *50 Sievert!*
That's like 0.28 Sievert per day for 180 days straight. That's nuts!
You sure it was 5000 rad, not 5000 mrad or something?
So sorry to hear what you are going through man....What kind of cancer is it ?
Nice video mate
This is a good example of the difference between the "first" and "second" story
The "first story" is what a lot of the more stupid comments are about: Who pushed the last button before the explosion and punish that guy because he is obviously the cause of it all.
The "second story" is about WHY things happened the way they did. Nobody at Chernobyl wanted to blow up the reactor, so why did they do the things they did?
Not WHO, but WHY.
The "why" is easy in this case: soviet culture, hierarchy, not wanting to disappoint and absolutely not wanting to contradict the man in charge, no proper understanding of the situation in the reactor (which is ALWAYS the problem in ANY nuclear incident).
Don't BLAME the worker, ask them why they thought that what they did was the right thing to do. If you blame, they will lie and you're just going to get the exact same thing with the next worker. A worker doesn't want to break things, but your process may have things in it that make it very probably that mistakes are made.
If you think "well, workers should pay more attention so they don't make mistakes" then you are exactly the kind of fool who enabled Chernobyl to explode.
Thanks for this and much I did not know. Desperately tragic.
You're welcome! I hope you enjoyed. :)
@@thatchernobylguy2915 Yes enjoyed it a lot. Im a Chernobyl nut. Been fascinated ever since the news came out in '86.
On a point of accuracy. The role played by xenon has been persistently mixed up and the mix up endures. Xenon is present in any running reactor. It had been burning off whilst the reactor was running at 50%. If the reactor shutdown had not been paused for most of the day the levels of xenon would have been higher causing deeper poisoning. That would have meant more poison to offset the az5 power spike. So there was less xenon in this shutdown that there normally would have been.
And similarly it was not the cause for the power drop because the drop would have been even bigger without the shutdown pause.
@@Mike-Bell I am well aware of this; it's specified in INSAG-7.
@@thatchernobylguy2915 Ok its just that the you said xenon had started to accumulate as the power was reduced. Xenon had been present for months.
@@Mike-Bell In the period of lowering the power down from 1600MW(t) to 500MW(t) before the sudden power drop at 00:28, there would have been a marked increase in xenon concentration. Again, this is specified in INSAG-7, page 64 to be precise. This sudden increase in xenon would have made the reactor harder to control and could have led to the reactivity falling below the 700MW(t) specified in the programme. It was this xenon that would then go on to reshape the power density field.
The period between midnight and 00:28 is really hard to explain, because nobody has ever directly specified why they let the power fall so low before the sudden loss of power. It's something I am interested in making a video on, but I have a lot of videos I want to cover and a finite time in a week. :)
He was a smart guy, so I think any mistake he made were due to a lack of training and flaws in the reactor design.
Good, interesting video. Thank you very much!
How could he be guilty of causing a condition that he knew nothing about? He followed procedure.
Do you plan to make similar video about Akimov?
Pushing AZ5 would have made the reactor safe had the tips of the control rods not had a moderator, i.e. carbon on their tips which briefly sped up the chain reaction.
The major design flaw was that the control rods had graphite on their tips (which causes the reaction to increase) which had to be inserted before the rest of the rod (boron) entered. So as soon as the control rods started to be lowered the graphite caused the reactor to get much hotter. This caused the water in these cylinders to be instantly evaporated creating so much pressure that the rods were unable to continue downwards to regulate the reaction.
The whole core was doomed before that button was pushed. There was no way to prevent it.
This whole incident is just horrible. From the injury and death of Toptunov and the way he was considered wrongly at fault, to the harm to people around the plant; and the harm to the perception of the safety of nuclear power worldwide. It is just a tragedy unequaled.
The operators of the reactor were unqualified to conduct the test,same as asking someone unqualified to time a vehicle engine.
Very interesting video thank you.
This 25 year old boy destroyed and collapsed an entire 60 year old union state with a single button.
A button that, I might add, was advertised and allegedly designed to SLOW and STOP the reaction rate of the reactor, and yet, BY INHERENT POOR DESIGN, actually INITIALLY INCREASED THE REACTOR RATE. Yet NONE of the operators were EVER trained on this curious "feature" of the system. HOWEVER, this behavior was discovered BEFORE Chernobyl, when the initial insertion of control rods in another RBMK reactor at Ignalina Nuclear Power Plant in 1983 induced a power spike. Procedural countermeasures were not implemented in response to Ignalina. The IAEA investigative report INSAG-7 later stated, "Apparently, there was a widespread view that the conditions under which the positive scram effect would be important would never occur. However, they did appear in almost every detail in the course of the actions leading to the Chernobyl accident."
@@philroe2363 I believe I read somewhere in one of the many books and articles about the disaster that after the close call at Ignalina there were a series of safety recommendations offered by the investigation, but none of those recommendations were implemented because it would have been tantamount to an admission that the reactor design was flawed. I know Dyatlov maintained this claim until his death, it was central to his assertions that he had been lied to by omission. He was certainly very strongly of the view that had the relevant authorities heeded the warnings, implemented the safety recommendations, and informed staff accordingly, the Chernobyl disaster would never have happened. Given all that has been learned since it's pretty hard to dispute his claims.
This interpretation of events is technically and historically wrong.
@@cymbala6208
Gorbachev himself said the Chernobyl was the main reason the Soviet Union collapsed
@@FP194I'm sure he had his reasons since it was his ambition to keep it together and modernise it. Everyone needs an excuse.
I understand that the fate of the reactor had been sealed already before the AZ5 button was pressed. Which means that, at that point in time, it would not have been possible to prevent the explosion, even if some (any) other course of action had been taken. I think the crucial mistake was when all of the rods were removed to force a power increase, which led to the reactor becoming a time bomb, and the explosion became inevitable.
Yes I believe you are correct. Xenon poisoning has a cycle time measured in minutes. As we know now (too late) the only safe course of action was to abort the test when the power level fell too low. According to the final report, the tips of the obsolete control rods slowed the neutrons, greatly increasing fission in their vicinity as they were being lowered. As you probably know, the reactor core did not explode, despite widespread reports. Rather, it was a steam explosion resulting from a combination of the resulting power spike and also the high temperature of the feedwater. Instead, a shutdown and warm start would have been infinitely more safe. A tragic loss of life, and those who blame this bright and dedicated young man, do so from a position of ignorance.
@@kevinamundsen7646 It doesn't matter if it was a steam explosion, said steam was in the core ergo the core exploded. Don't try to confuse people with pedantry, no one said it was a nuclear explosion - they just said the core exploded.
@@kevinamundsen7646 I'm not saying you've necessarily misunderstood the control rods but the way you explained it it looks like you might have. The control rods didn't have a graphite tip, they had 4.5 meters of graphite rod on a follower so that the control rod could act both as a break and as an accelerator; giving more bang for your buck (less control rods and lower enrichment of the fuel). This graphite didn't leave the reactor when the rods where withdrawn, it was withdrawn into the center of the reactor as the neutron poison was lifted out of the core. The crucial error was that the rods could be withdrawn so far that it left the lower 1.25 meters of core without either control rods or graphite. During normal circumstances where the neutron distribution was even throughout the core this meant that reactivity dropped immediately when you pushed AZ-5 and everything was fine. You'd push some water out of the way in the lower 1.25 m increasing reactivity locally, but the amount of graphite in the core didn't change so the overall effect of that would normally be zero; the only thing that did change was that control rod started entering the top of the core; so overall reactivity would drop and it's fine.
In this particular case; that's not what happened and much of the activity was already occuring in the lowest part of the core; when the rods dropped it accelerated activity in the part where there was already a lot of activity and it slowed activity where there already wasn't much activity; the net effect was an increase in power.
@@soylentgreenb Thanks for your reply and explanation! You are correct, I don't fully understand how the telescoping control rods work. Do they have 2 servomotors (or selsyns) instead of one, to control the top and bottom parts individually? I'd like to see an animated video showing the design. A big thank you to the creator of this series, providing a good human touch to the subject. I've met several of the nuclear guys and greatly admire and respect them for their courage and brains. To All, please consider a career in the power business -- great people, interesting work and the pay is good.
@@kevinamundsen7646No no, they aren't independently controllable things; it's just a single piece with a telescoping section. The rods were made of 7 meters of boron carbide absorber, a 1.25 m telescoping section and 4.5 m of graphite rod. The telescoping section is completely passive and just slides in and out like a radio antenna. When the rod is not fully inserted the weight of the graphite extends the telescoping section. When the control rod is being fully inserted the graphite rests at the end of the control rod channel and the telescoping section collapses. The telescoping section allows the control rod channels to be 1.25 m shorter.
Leaving 1.25 of water at the top and bottom of the reactor when the control rod is fully "removed" and only graphite remains in the core was also purposeful. This allowed them to shape where the neutron flux was located in the core, but it played a big role in the accident.
There were also several different kinds of control rods that differed in design (including pure absorber rods that are used to compensate for the freshness of the fuel). The ones that are discussed usually are the ones that were blamed for the accident. As the fuel is consumed, you get more Pu-239 and less U-235 and you have to remove absorber rods. For reasons that are kind of complicated to explain this makes the reactor less easily controllable (larger void coefficient, shorter time scale of power changes) as the fuel ages in the reactor.
I don't think we should blame this man. He did the right thing not knowing anything about the problem with the control rods.
The reactor was an accident waiting to happen, it was only a matter of time before disaster happened!
Many Many Faults, because it was cheap and easy to build the Soviets hushed up it’s many faults.
The reactor didn’t have a confinement building and when it exploded the radioactive core was ejected into the atmosphere.
The reactor had a positive void coefficient meaning that when the temperature rises more coolant turns to steam causing the reactor to run away
In my opinion and understanding of it i believe top did everything in his abilities and knowledge and experience and only tried to prevent a unstoppable chain of events leading up to the meltdown and did everything accordingly.
But if it is true that the reactors system was faulty then it really wouldn't have mattered what they did it still would've meltdown and exploded.
From start of rapid power increase to the point of the explosion was 30 SECONDS, something that the instrument recording devices show , and would been real time control panel instruments both Toptunov and Akimov would seen and watched.
It would be after 15 seconds since beginning of rapid increase of reactor power from below operational they would notice how fast the increase was , while only 15 seconds more to the reactor power being over its maximum operable power whatsoever and the instruments and recording being disconnected because there was nothing there from explosion disintegration.
Pressing the AZ-5 probably did not get it's signal received by the machine because the control rod machine were probably not there at that moment, and if the control rod machine were there , the signal command would take part of a minute to execute anyhow, just as going from lowest power to maximum allowed reactor power requires at least part of one hour to safely commit at its fastest not the impossible "under one minute"!
A waste of time for both Soviet courts, and international atomic safety organisations or any other moratoriums to blame either Akimov or Toptunov.
By all likely data, the AZ-5 button did nothing even if it had been connected for a few "seconds" until the explosion!!!!
The Fact That Dyatlov is like: We need to shutdown the reactor? nah continue the dest the SKA Computer doesnt even know we are doing a test.
Looking at videos of these nuclear stations operation fascinates me! I could only imagine how prestigious it would’ve been to be a nuclear operator in Soviet Union!
Well, it would also have been an extremely boring job, because back then you'd sit around for decades and nothing would happen at all, a bit like watching the hot water heater in your basement in great detail. The IAEA found that after years of this uneventful boredom, it becomes psychologically hard for operators to believe anything can go wrong. I've heard that in modern reactors in the USA, now the operators split time up between operating a reactor and operating a simulator, where the simulator runs through all sorts of hypothetical problems and disasters to be warded off.
Following the Swiss Cheese model it is clear that Toptunov plays only a minor role in everything that happened.
The whole thing started when a nuclear physicist descibed the first time, in another acciedent with an RBMK-1000 a few year sprior, that pushing the AZ-5 when the reactor went over a certain thermal power limit (and other same symptoms at Chernobyl NPP that night) the displacement of water is too rapid and causes a massive spike in thermal energy, due to having no coolant at hand and by faster compression of the not so fast dispersing water and thermal splitting of water into its molecules, a hydrogen explosion has to be expected.
This was disregarded by Soviet management because the RBMK-1000 was state of the art Soviet technology back then and the most powerfull reactor on Earth of its time. It would damage the imagry of Soviet technology and therefore this very important critique was put down.
The next part is about how very important obedience towards senior leadership, relationship with senior leadership and subsequent ladder climbing on soviet society was. Toptunov had a very beneficial time in his life till the day he was promoted into seniority. A path almost everyone would choose if the opportunity would have been presented. This seniority was even placed above technological surveilance. A reason why a senior inside Chernobyl had more power than SKALA eventho SKALA was the most sofisticated piece of technology a soviet NPP could have. Very reliable computanional machienery.
Toptunov merely followed orders given to him and tried his best to follow through eventho, I assume, doubted them himself. But he had no choice but to act accordingly. Otherwise, if things would have went smoothly as other would have taken over his position after being dismissed by seniority, he would have been in a very bad standing and possibnly would have lost his working place at Chernobyl NPP. (And subsequent all amenities that came with it).
So in the final seconds he relied on the training he got and on his supervisors orders and pushed AZ-5 in full hope that it would resolve everything miraculously...
Boom.
And, if anybody really would blame him on his duty, he redeemed himself when going down to secure emergency water cooling towards the reactor. His sucumming to radiation poising is the followup tragedy. I classify him as a person done a heoric act that night.
It was not a fault of one man. Who pushed the button or whether it was pushed or not was irrelevant, the reactor was done at this stage. The button only accelerated the event. The whole reactor crew on both shifts was to blame plus the design. No reactor cover was the main issue. Three Mile Island had similar event as Chernobyl, yet consequences were way smaller. Same goes for Fukushima which was 10x worse than Chernobyl (multiple reactors were damaged, yet technically no casualties cause by reactor explosion/radiation). This is what you get when nuclear material for bombs is more important than safety.
If there ever was a victim of circumstances Toptunov was that. He was a genius that was placed in a position and at a time that killed him and many others. A very sad story.
Didn’t the HBO series show Akimov pressing the AZ5 button ?
Yes, but HBO was incorrect. This is one of many mistakes in the show. I may elaborate on them in the future.
The image of hospital number 6 is incorrect btw.
This may be a good time to turn that final statement around. Had AZ-5 not been pressed, would not the reactor have exploded?
The answer, I think, is no. The reactor was going to explode whether AZ-5 was pressed or not. The sequence of events was already in motion. The power spike was underway. There weren't any control rods in the reactor; its condition was unrecoverable. Even if coolant flow was restored, the reactor was in a condition where it would have immediately vaporized. The pressure in the inside would have still gone high enough to lift the biological shield.
there was no power spike prior to AZ-5, AZ-5 caused the power spike and it was AZ-5 alone.
When all of those fully withdrawn rods went back in, and the short graphite displacers pushed through the previously empty and un-active column, energy spiked.
This is a good video
Seems to me the question is if Toptunov didn't push AZ5 what would have happened instead? Maybe it would have still blown up, maybe not. Maybe this reactor, or another rbmk, would have blown at some later time because the whole point is it was a shitty design to begin with. That, and the sub-standard soviet nuclear safety program is to blame for the disaster. Not Toptunov.
The fuse was already lit but they had no idea, when they hit A35, similar to a flashover in a fire, the fire was burning, A35 just was the final charge. Like oxygen into a fire, it was just another ingredient to tragedy.
That is a horrible thing to even think.
Amazing!
Thank you.
Will you make a akimov half lives
Leonid's other job was reading out the Top 40 on Chernobyl FM.
Now I'm angry at the chernobyl series Why would they make it seem like dyatlov Hated them and had called them incompetent morons. He's writing letters exclaiming that they were not at fault. Having their backs. It's really not right then the way he's betrayed in the show
Every time we see what is left of the reactor 4 control room, it is in worse condition. It can't be canabalisation sinse all the reactors are shut down. So who the hell is getting away with stealing radiated metalic souvenirs?
The power droppped because they disconnected the automatic systems which controlled the reactor as part of the test. And that's not all they disconnected. The reactor fell into an iodine well and Dyatlov insisted that Toptunov restore power so the test could proceed. Toptunov initially refused, and then when threatened by Dyatlov, he started pulling control rods out. Dyatlov, and Fomin, the man who drew up the test proceedure are to blame for this disaster. Poor Toptunov would not have proceeded as he did had Dyatlov not been there sceaming at him. The graphite tipped boron rods were the last straw, and although Toptunov pressed the scram button, he could not have known the consequences the initial insertion of the rods would have had. No one was aware of the previous incidents at ignalina and one of the other reactors at Chernobyl.
Soviet reactors are infallible.
Absolutely nothing you just said was accurate.
Your statement is not accurate. And you think irony is when you flatten a shirt. @@MinSredMash
@@bloodyhell451 And you think HBO is a documentary. The power drop had nothing to do with the test preparations. And there is no evidence of Dyatlov threatening anyone to do anything. Not a single quote from any of the one dozen plus eyewitnesses. If you disagree, then prove it. And while you're at it, please explain what the test procedure had to do with the accident.
I want to mention a problem in China. They built the HTR He-gas-cooled reactor. They "inherited" a fundamental problem of this experimental Germany-designed Kugelhaufenreaktor (60mm-ball-spheres heap reactor). The core has a cylindrical, vertically high shape! That is bad. A nuc-core always should be perfectly spherical, so that any accidental deviation of the geometry reduces the reactivity. A vertically stacked cylindrical core potentially could change and get supercritical. This reactor also has a problem with the control rods. At least some (the most important) rods should be inserted from below, moving up in the heap! The control rods coming down from the top could get stuck in the heap. Or maybe control rods coming in from the side would be more mechanically reliable?
Pressing the AZ-5 button didn't blow up the reactor. Removing almost all of the control rods with the core in xenon poisoned state blew up the reactor.
Watched the HBO series, who was the guy who came running into the control room and said there was a fire 🔥 in the turbine hall
That was Vyacheslav Brazhnik in real life; after he ran in and reported the fire he ran back to the Turbine Hall to fight the fires, and a large number of people including Dyatlov followed him. Brazhnik ultimately received a lethal dose of radiation fighting those fires and trying to prevent another one breaking out.
This is one big sad story of one young and ambitious man. I know that he (and the other operators) was't the reason why this everything had happend. Although, in my eyes he still got some responsibility for that. Yeah, now it is easy for me to say that. On that night pressure must have been enormous, but i guess nuclear reactor operator should be able to deal (at least a bit) with situations like that was.
That was problem of USSR, people who weren't qualified enough, worked on positions, on which they souldn't.
The man that blew up chernobyl was the man who gave the orders. If a captain orders a mate to turn left And a ship runs aground, it wasnt his fault, he did what he was told.
There were numberous people responsible for the Chernobyl disaster. This started with the decision that a reactor with a positive void coefficient was a good thing, continuing with the decision that tipping the SCRAM rods with graphite and limiting their insertion speed was a good thing and making the SCRAM button (the AZ5 button) a momentary contact was a good idea. All these people responsible for these decisions were responsible for the ensuing events.
How can you possibly have a button that is supposed to shut down the reactor, hard, in the event of an emergency ALSO be designed to send the reactor out of control in certain emergencies? This is a horrible design flaw that tipped the reactor over the edge from emergency to disaster.
Please stop saying graphite tips. They weren't graphite tips; they weren't there as an accident. They were 4.5 m long graphite displacer rods attached to the control rod on a follower and they were put there purposefully so that the control rod could act both as a break and as an accelerator; giving more bang for your buck (less control rods and lower enrichment of the fuel). This graphite didn't leave the reactor when the rods where withdrawn, it was withdrawn into the center of the reactor as the neutron poison was lifted out of the core. The crucial error was that the rods could be withdrawn so far that it left the lower 1.25 meters of core without either control rods or graphite. During normal circumstances whene the neutron distribution was even throughout the core this meant that reactivity dropped immediately when you pushed AZ-5 and everything was fine. You'd push some water out of the way in the lower 1.25 m increasing reactivity locally, but the amount of graphite in the core didn't change so the overall effect of that would normally be zero considering the graphite displacer; the only thing that did change was that control rod started entering the top of the core; so overall reactivity would drop and it's fine.
In this particular case; that's not what happened and much of the activity was already occuring in the lowest part of the core; when the rods dropped it reactivity in the place that counted and decreased reactivity where it didn't matter; the net effect was an increase in reactivity and power. If the graphite follower had been longer or it had been impossible to withdraw the rods this far the accident couldn't have happened the same way that it did. The mistake here was subtler than people give it credit for.
Seriously?? They were lied to about serious design flaws.
Blaming the guy that pushes the AZ5(scram) button is so ridiculous.
When all the cars got recalled because the stuck accelerators we didn’t blame the drivers. ITS THE MANUFACTURERS FAULT. ESPECIALLY WHEN INFORMATION IS SUPPRESSED BECAUSE OF SOCIALISM and bureaucracy.
In the TV movie Anatoly Dyatlov was to blame.
He was in charge barking crazy instructions .
Until something blows up they played fast and loose with nuclear power, the real experiment was if we do all these crazy things will the reactor blow up.
The person to blame is Dyatlov is the one to blame for blowing up the reactor ignoring those around him and ignoring the condition the reactor was in.
Nah, the real criminals were in the Kremlin, Dyatlov was an arrogant arse but he was as much in the dark when it came to faults with the reactor as anyone else was.
Not just Dyatlov. I recommend reading Legasov's account of the soviet nuclear program that he made before his suicide. (Read the actual account, not the HBO portrayal of it.) He said that management problems with poor attention to risk in the Soviet nuclear industry were so pervasive that a serious accident was inevitable. The account is reminiscent of Richard Feynman's account of why the space shuttle blew up: It wasn't just a failure of a particular component (an O-ring) but more generally there was a serious mismanagement at NASA where higher ups didn't want to hear about risks from the "low level" people who did the engineering. Similarly, the IAEA report details that the Fukushima management had been already warned a few years earlier that the sea wall was too low, but they spent years considering the problem instead of fixing it. The story of how it was realized that tsunamis get that high is quite interesting, since it was realized by a an archiologist who saw evidence of high tsunamis in his digs, not by some ocean scientist or anyone like that.
The culprit is the inexperienced shift supervisor who was on duty that night of the incident, and his "seniority complex". He should have left it to the experts, who was younger than him.
Uh, no. If you're talking about Dyatlov, everyone idolized him as the most experienced and knowledgeable person at the plant.
I am confused. Would not inserting control rods lower the thermal output? How could inserting the control rods initially cause a power surge?
Watch the movie. The rods were not tipped with the correct material .
@@Crashed131963 Ah, I will find the movie and watch it. That may explain the quick powwr surge when they are initially inserted, that was mentioned but not really addressed very well in the video. If the reactor is already highly over driven, putting in rods with the wrong material tip could act like a reflector initially. I must watch the movie.
Don't watch the "movie" this guy is wrong. You'd probably need a visual demonstration, but I'll try my best to explain.
Once fully removed from a channel, the control rod's graphite displacer (used to accelerate reactivity) was slightly too high, leaving a space without much reactivity below it in the channel, once the control rod is inserted, the graphite displacer moves into place and fills that gap, accelerating reactivity.
I believe that is Boris Stolyarchuk at 0:31?
Yes, it is.
His family was informed by authorities that his death from acute radiation poisoning was the only reason he was not prosecuted. (!!)
He and his poor family ❤. Bad government, cheap and hastily built. He did the best he could but was gravely misinformed. I hope they know peace and be ever so proud of their family’s accomplishments. Governments think their constituents are expendable.
when your entire channel revolves around one man, one event, and one place.
Well you got two out of three correct.
The corrupt, slipshod, and completely ineffective design & building of the plant, in addition to the grossly ineffective maintenance, management, training and disaster planning, made this catastrophic event bound to happen. These operators had the deck stacked against them from the beginning. They are the conveniently dead fall guys for the Soviet system to blame for their own gross negligence.
The background music is a distraction. TD Atlanta
I don't think we'll ever know the truth 100%.
This occurred in the Cold War Soviet Era, where people's testimony and evidence were expected to always be altered and confusing.
The State and those in positions of authority could never, by definition, be blamed.
But the witness testimony and scientific data is consistent. The only things that aren't consistent are the things that have since been proven to be made up, like Medvedev's book which had been denounced by every single survivor.
Interesting comment.
It was Anatoly Dyatlov who was responsible, by ordering them to ignore SOPs.
He should not have ordered them to raise the power, when the reactor was suffering from Xenon poisoning.
He was way too young to die! What a waste of and smart and handsome man 😢. I am pleased to hear that his name was eventually cleared from it being "his fault".
Damn. That poor kid. If he had been expelled from college he might still be alive. Granted he might not have been as happy with his life. But he'd still have a life to not be happy about.
Blame Anatoly Dyanlov sub incident who once messed up at a shipbuilding plant in Komsomolsk-on-Amur, in Lab 23 where reactors were installed into submarines. During a nuclear accident there, Dyatlov received a radiation dose of 100 rem[1] (1.0 Sv). Chernobyl was a accident waiting to happen.
Don't spread ignorant bullshit. There is no information about Dyatlov being responsible for that accident.
could this previous rad accident have had some lasting effect on his health, maybe a negative effect on his decision making, additionally to the difficulty of night shift work, when it gets too complex!
Besides that possibility, there is an obvious lack of passing important information up and down the hierarchy. Especially passing info upwards anonymously, like aircraft pilots have such a system in place, is missing. Otherwise important info about mishaps is brushed under the rug, and not reported!
Who is to blame for Chernobyl? Simple: the people in authority that allowed the continuation of a KNOWN marginal design in the RBMK-type nuclear reactor. What kind of reactor design would actually go critical upon the PUSHING of the SCRAM button??? The RBMK has a positive void coefficient of reactivity at low power levels. This means that the formation of steam bubbles (voids) from boiling cooling water intensifies the nuclear chain reaction owing to voids having lower neutron absorption than water. The operators were not trained about this physical fact. Further, a bigger problem was the design of the RBMK control rods, each of which had a graphite neutron moderator section attached to its end to boost reactor output by displacing water when the control rod section had been fully withdrawn from the reactor. That is, when a control rod was at maximum extraction, a neutron-moderating graphite extension was centered in the core with 1.25 metres (4.1 ft) columns of water above and below it.
Consequently, injecting a control rod downward into the reactor in a scram initially displaced neutron-absorbing water in the lower portion of the reactor with neutron-moderating graphite. Thus, an emergency scram could initially increase the reaction rate in the lower part of the core. This behavior was discovered when the initial insertion of control rods in another RBMK reactor at Ignalina Nuclear Power Plant in 1983 induced a power spike. Procedural countermeasures were not implemented in response to Ignalina. The IAEA investigative report INSAG-7 later stated, "Apparently, there was a widespread view that the conditions under which the positive scram effect would be important would never occur. However, they did appear in almost every detail in the course of the actions leading to the Chernobyl accident."
The RBMK-type nuclear reactor is an inherently UNSAFE DESIGN.
Wouldn't the reactor be past the point of no return by the time the AZ-5 button was pressed?
If it worked as advertised, it would have saved the reactor.
unfortunately the reactor was near critical when the scram button was pushed. this dropped all the control rods quickly, but that led to a momentary surge in neutrons that sent the core over the edge and caused a runaway chain reaction, before the rods had a chance to absorb neutrons. but yes many believe the reactor would have gone critical regardless of the az5 scram.
Practically all the control rods had been removed. It was too late. The graphite tips gave an additional spike to the reactivity. Promt criticality occured.
And in worse the rod canals bended from the heat which meant that put back rods stayed half inserted and infinately accelerated the reaction.
It was truly one of the worst case scenarios