Chernobyl's Unanswered Questions: How Many Control Rods Were in the Reactor When AZ-5 Was Pressed?
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- čas přidán 3. 06. 2024
- The official reports into the Chernobyl Disaster cover a large amount of information surrounding the fateful events that led to the world's worst nuclear disaster. However, these papers still miss key details pointed out by others that dramatically alter the story even scientists have come to expect. These are Chernobyl's Unanswered Questions.
One single violation of the operating instructions pertinent to the disaster has stuck since the beginning - the Operating Reactivity Margin expressed in number of effective control rods present in the core dropping under the minimum permissible value of 15. As by now you wouldn’t be surprised in the slightest to learn there is a lot of funny business going on in this topic. The contextual lies and misrepresentations of the ORM belong in a different video. In this video we will focus on an unanswered question - what was the ORM at the pressing of AZ-5? As the positive scram effect that initiated the destruction of the reactor is partly attributed to a low ORM in violation of the operating instructions its value at the time of the shutdown button press is a central question, one that should not be unanswered (and even unknown as a point of controversy) some nearly 40 years after the disaster. The obscurity may be deliberate.
This script was written by Bobby, who has also crafted an incredible history paper exploring how misinformation and disinformation continues to impact the story of Chernobyl. You can read it here: docs.google.com/document/d/1m...
Sources
HBO Chernobyl
INSAG-7
Anatoly Dyatlov - How It Was.
INSAG-1
The Accident at the Chernobyl Nuclear Power Plant and its Consequences
On the development of the RBMK-1000 project (A.N. Rumyantsev).
Data Collected by Victor Dmitriev, accidont.ru
The Chornobyl Accident Revisited
• Как можно было предотв...
Chernobyl: Revenge of the Peaceful Atom
Anatoly Dyatlov - Why INSAG has Still got it Wrong
Computational Analysis of the initial stage of the accident at the Chernobyl' atomic power plant
ДИНАМИКА ЯДЕРНОГО РЕАКТОРА С РАСПРЕДЕЛЕННЫМИ ПАРАМЕТРАМИ В ИССЛЕДОВАНИЯХ ПЕРЕХОДНЫХ РЕЖИМОВ ЭКСПЛУАТАЦИИ ВВЭР и РБМК
Minutes of CC CPSU Politburo Session (Anatoly S. Chernyaev notes)
![[REUPLOAD: IMPROVED AUDIO] Oceangate Titan: analysis of an insultingly predictable failure](http://i.ytimg.com/vi/4eNm8vnKZ38/mqdefault.jpg)
Good job. This video took a lot of effort to make but it's very important in accurately understanding both the disaster and the effort made to scapegoat the operators. The unanswered question it raises is vital.
21:00 "However, the reduction of feedwater flow as well as total flow during the test caused SUFFICIENT rod insertion to reverse the preceding ORM reduction."
26:30 Incorrect portion shown. The Soviet graph is basically an uncolored version of the INSAG-1 graph shown earlier.
34:42 An ORM "within" regulations.
Also, purported rather than reported.
The fact that they had the computer room 40m distance from the control room in 1986 is mind boggling, I wonder that if they had control room computer feedback things might have been different - clearly there were just too many things happening for human control. RMBK is a simple design in theory but clearly it was far more complicated in reality.
Also the SKALA computer was using core-memory in the 1980s... 1960s technology in the age of DRAM. I understand the Soviet Union was behind in all computer technologies, but they had their own PC industry using their own DRAM modules during the 1980s and they didnt think to modernize their nuclear powerplant computer mainframes? Priorities in the wrong places IMO.
To play devil's advocate: it is not uncommon for critical infrastructure to be running on what in almost any other context would be seen as antiquated hardware, for the simple reason that you want something with a proven reliability record for both safety and financial reasons (putting a nuclear power plant offline because the Computer systems need to be fixed on the fly would not go over well)@@supabass4003
@@supabass4003priority probably went towards army first
I heard US Nuclear arsenal is governed by 3,5" discettes,...
Dude, this is far the best channel regarding RBMK technical informtion and the whole Chernobyl accident (also i like the RBMK5000 channel!).
Could you make a detailee video about how the control rods worked, location of servos, how did they move in the reactor, how was the system made pressure-tight, did they just move in technological channels,....?
TL:DR - it wasn’t operator error
the attention to detail and research in your vids deserves millions of subs.
This channel still stands to be one of my favorites when it comes to chernobyl, the subject is so intriguing to me and i love learning more about it
Wow, a whole channel dedicated to pushing the Chernobyl HOAX! Shameful.
Wow! what crazy detective work it needs to put all the puzzle peaces together!
Great video, technical and a little above my head but still a great video. Thanks
You're welcome, glad you enjoyed :)
Sir… again I’m totally blown away from your content. It was a pure pleasure and a great joy. Thanks for all the hard work you put into this. Your friend from Germany 🇩🇪. Go on. It’s like a journey for us. Listening to this with my wife and also she’s more than excited to hear about new videos coming soon.
Absolutely fantastic work here, thank you.
Great video, but can you put some more ORM in it next time?? ;-)
Thanks, Best Channel on CZcams based on Chernobyl, Love From India 🎉
Personaly i think the disaster happened due to a few different factors that all stems from the same place, poor reactor design. They built a reactor that was highly unpredictable at low power settings, where you have several things that can trip it up. Feedwater flow, feedwater temperature, control rods and their actual positioning in the core. At normal power production settings it is rather well behaved but a bit hard to control as you can have hot spots in some areas and cold spots in another.
What i think is the most overlooked in the actual accident, is that most control rods were at the same place, ie fully withdrawn, so when you insert them into the core all the graphite moves through the same layer at the same time, so you will automatically have a power surge due to that effect alone.
In combination with reducing xenon poisioning and reduced flow rate of feed water, the effect of the control rods basically sealed the deal, but i think it was probably already too late at that point it was so out of normal behaviour that the operators didnt know what would happen. So the poor design caused the disaster, those who built the reactor on paper should had seen all the graphite tips and said to themselves "at low power settings with most control rods pulled out due to xenon poisioning, what will happen if all the graphite passes through the same layer in the core at the same time?"
Usually in normal operating margins there are control rods all over the place at different depths too, so pressing the AZ-5 there will keep their relative positioning to each other the same through the full insertion so you actually wont see a power surge. However if many of the control rods are fully wihdrawn you will get a power surge as in one layer there is only more moderation and no control rods at all.
I can paint a picture for you, lets say you have one control rod fully inserted with the graphite tip at the bottom of the core, a second control rod next to it iniserted so the lower part of the graphite tip is at the same layer as the upper part of the first one, and another control rid with its graphite tip at the upper part of the second control rod. What happens if you push the AZ:5 here? Well nothing really all 3 control rods just inserts through the core. But if they are all out of the core? Well all the graphite goes through the same layer through the core at the same time.
So the AZ-5 button is basically a suicide button when almost all control rods are out of the core. During normal operation this is never experienced in any way. So this was not something the operators thought about, it was an unknown to them, and even to the designers and their scientists.
I don't know if I can explain why I am so fascinated by your channel, but I find it absolutely amazing with the amount of content, the presentation, I find the voice extremely soothing with a great amount of emotion to go along with it. There is always a great amount of visualizations or images that contribute to the overall subject, but I get most of the information still through the narration. Thank you for doing what you do... I never thought this would be so interesting and I love it. 😊🌎❤️🕺🏻
I am a Chernobyl history fan myself and really enjoy your content. Thanks!
great work. Although i probably have to watch this video a few more times to completely comprehend everything because it is a lot to take in!
Now this was time well spent! Amazing job on the video. The only thing I'd like to get is that Russian research book you showed towards the end. That is something I would very much like to read some day. The wait for a new video of yours is always rewarding.
Which one? If you send a timestamp I can link it :)
@@thatchernobylguy2915
That would be great! The title is at time stamp 34:05, the book from Galimonchuk with the blue/grey cover with the cooling towers on it^^
@@swokatsamsiyu3590 Courtesy of the IAEA: inis.iaea.org/collection/NCLCollectionStore/_Public/40/108/40108236.pdf
@@MinSredMash I thought this was supposed to be from a decade later? Has the author been on about this for years?
Alright, so in the document that was actually used for this video the screenshot you see at 34:20 is on page 218 rather than 176.
Fantastic work!
Gosh. Very thorough! Great work. Confess my A level physics was exhausted quite early on in that essay!! This is the point at which i need pictures and animation. 🤯🤣
Why did the operators wear baker's clothing?
Good work
I like to see that Zero from GTA:SA found a new passion with this channel. And i like the topic too. Nice work m8 :)
Nice. Again. Great workYou can continue about nuclear safety easyly...
I run and maintain distillation columns at my work. Seeing those graphs felt familiar due to trending parameters at work often. Thanks for the cool info.
Brilliant!
MORE!
So 38 years after, and we still dont realy know why,...
can you make a timeline of chernobyl sometime? i find it hard to understand what exactyl went down in the reactor esp rigth after, liek where the melted stuff flowed
Can you make a Vid about the german Concret pumps or the Demag cranes ???
"How Many Control Rods Were in the Reactor When AZ-5 Was Pressed?"
I can answer this question; "not enough".
How Many Control Rods Were in the Reactor When AZ-5 Was Pressed? Not enough...
Possibly enough to not have been in violation of the operating regulations. That the reactor would explode nonetheless is telling as to where the real causes of Chernobyl lie.
What do you think would have happened if AZ-5 was never pressed?
There would have been an automatic scram shortly after the button was pressed, as the power would have eventually begun an excursion, so no matter what at that point, the reactor was doomed.
About the same outcome.
@@thatchernobylguy2915but weren't at least some safety systems disabled during the test? Would the automatic scram still happen?
@@yarost12 Protection was still in place against a power excursion. The protections that were disabled or changed were done so according to various instructions and were not total. From page 78 of INSAG-7:
"The changes made to the set points and deactivation of the engineered protection and blocking systems were not the causes of the accident and did not affect its scale. These actions were not in any way related to the emergency protection systems of the reactor itself (relating to power level, power increase rate), which the personnel did not deactivate."
@@thatchernobylguy2915 Unless someone had known that they should insert the USP rods first, to counteract the tip effect. Then it was still avoidable.
What’s going on with your audio getting cut off at the end of sentences?
Yes. C(hernobyl)3P0 with another top video. They keep coming. Theres nothing else like them on YT.
Ill tell you exactly what happened, the designers of the RBMKs just guestimated some shit, and didnt understand their design completely.
Thats what tends to happen when you build stuff at such a scale that previously borderline irrelevant unknowns turn into a huge problem that turns your final product into a disaster.
I heard somewhere that they were very much aware of the pitfalls reguarding the reactor but didn't add it to the manual or train the operators for fear of sabotage.
It always seemed abit of a dud theory to me and more likely that they didn't want a loss of face.
So if I get this right, there was two minute window in time (upon cold coolant entering circulation) when SKALA, would have suggested 7..8 rods _anyways_ if they had requested a report in that time window?
From past 01:19 to 01:21:50 there was elevated feedwater flow that would have resulted in the extraction of control rods. From 01:21:50 there is a substantial reduction of feedwater flow that would have resulted in the insertion of control rods, and then the test itself would have resulted in further insertion. The PRIZMA sub-system of SKALA that was responsible for calculating the ORM was not good operating in such dynamic conditions. It took from 5 to 15 minutes just to produce a calculation. There were scheduled printouts at 1 am and 3 am. The printout at 1 am apparently did not raise eyebrows, which, by the way, INSAG-7 is completely silent on too. There was effectively no printout at 01:22:30. It's rather unclear to me whether there was any physical printout whatsoever in the computer room 40-50 meters away from the control room or if Soviet experts retrieved data from memory and used that when calculating the ORM low point after the disaster at a different nuclear power plant altogether.
There's one high priority video left to do which will show you how far Soviet experts went to scapegoat the Chernobyl Unit Four operators. The Masters of Weaponized Narration.
At minute, 8:15 when he says number 3 and starts explaining it suddenly cuts and switches to number 4, can someone tell me what he said?
The word that is cut out is "core". The resulting coolant to have gone through the core. Really, there probably would be an overlap here with coolant of a different temperature moving through the core and compensatory rod insertion.
@@markusw7833 thanks!!
Lots of power for the duga oth radar🎉🎉🎉🎉🎉🎉
Why would the system allow less than 15 control rods to be present?
Because there wasn't enough computing power to track that parameter in real time. And it wasn't regarded as being relevant to safety in the first place, so why would they bother?
Because that parameter was never deemed that important prior to Chernobyl. In the early days operating an RBMK reactor with few control rods in it was deemed a testament of skill. Then a lower limit was implemented but it was apparently routinely violated and its significance was not related to the integrity of the emergency protection system. Other reactor types apparently had no lower ORM limits. It was a peculiar RBMK parameter that no one attached proper significance to. This lack of understanding was primarily the responsibility of scientific and design institutes. It was their job to design, understand, and consequently document these reactors for safe operation. They failed, historically. Chernobyl was by far first and foremost a STEM failure, not an operational failure. Everything was twisted after the disaster to make it seem like the latter rather than the former. Lies made it all the way up to the Politburo.
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do you specialize in nuclear or is this just a hobby?
This is just a hobby for me, it's a very interesting and deep subject :)
@@thatchernobylguy2915your passion is absolutely amazing and it shows from beginning to end. I found you a while back, but immediately looked forward to every video since and always a pleasure to watch! 🌎❤️
@@dancingwiththedogsdjNew Sub today 👍. I couldn't agree more. This was fantastic 👌🔥✌️😉
You know what this Video needs? It nedds more ORM!
I don't think the reactor was a terrible design... It was reliable after design changes were implemented
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Your editing has issues. You frequently cut yourself off in the middle of words.
This is propaganda from the west east north north and south
#korea
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