Chernobyl's Unanswered Questions: The Forgotten Truth of the Coefficients
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- Опубликовано: 3 окт 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 of the least generally known yet most startling things about Chernobyl is that the Soviets collectively appear to have had trouble accurately understanding the coefficients of reactivity, in particular the void and consequently the power coefficients. In other words, they appear to have misunderstood what would happen to the power of the reactor if water progressively turned to steam within it. This deceptively simple matter appears to throw off even the different authors of INSAG-7, the International Atomic Energy Agency report that is the top source on the causes of Chernobyl.
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.co...
GOD I love it when someone has an intimate understanding of their subject instead of just cranking out videos with Wikipedia grade research like 99% of "documentary" youtubers.
Impressive series of videos and an excellent narration.
Isn't it refreshing? BTW, I don't think you're being fair to Wikipedia. Wikipedia cites sources, is subject to revision, and compares favorably to print encyclopedias.
I love the designers being like "Im not sure what I´m designing, but I definitely wanna design that", then changing into "Oh its not that dangerous, lets just make it a little bit more dangerous by replacing stuff that makes it safe with stuff that makes it unsafe", and ultimately into "What do you mean that my design is garbage? Its those poor sods that operated it incorrectly!"
it was never the designer at fault, it was always the operators, this was the mindset in ussr. it didnt matter what was built, a tractor, a lathe, any other machine or, as in this case, a reactor, if you operated something and something broke because of the crappy design, you were at fault. they would change something to make it somewhat better, but still it was your fault and the change was made because they felt like changing it so you would not brake it again.
Really good insight to the real culprit for the disaster, Dyatlov was so easily made the scapegoat for the failure of a machine who many didnt really understand.
He was operating it according to the manual he was handed. Too bad some people that didn't understand how it work edited it after the reactor designer wrote it.
@@KnightsWithoutATable It's definitely a very interesting question who was responsible for what instructions, but it is clear in INSAG-7 the designers themselves failed in documentation. If you're referring to Dollezhal's appearance in this video, he is the only person any of us have seen claiming there was or there was intended to be a regulation limiting the removal of additional absorbers. As this affected the economics of the reactor it went to the very heart of things, more so than safety. Soviet experts plainly stated in their 1986 report to Vienna that the removal "of all or almost all" additional absorbers was intended.
As a nuclear professional who followed Chernobyl closely since the event. this uncertainty around the void coefficient is, frankly, shocking. A positive void coefficient is not necessarily a bad thing if well known and within design basis. But either a large positive void coefficient or large negative void coefficient can be a bad thing in a water reactor and can take you to prompt critical. Sadly, almost 40 years later, it seems the amount of misinformation around the event seems to be increasing. The popular miniseries contributed greatly to this misinformation.
Why would a large negative void coefficient do this?
@@markusw7833Well, this is just a guess, but because it's the opposite. Heh. No, really, though: that has to be the answer. That is, you have some liquid in there, right? If a positive void coefficient entails an increase in reactivity with an increase in voids, a negative void coefficient would therefore entail an increase in reactivity with a decrease in voids. I don't know the specific scenarios (at all), but I have no reason to believe that the latter is somehow IMPOSSIBLE given reactor design [x]. Thus, as OP stated, what's important is proper operation of the reactor given its particular characteristics. (EDIT: Some of which, I should add, were state secrets in this case that the operators didn't know about, but I digress...)
I have noticed that some people (not you--I mean am curious as to the specifics as well) seem to believe that this has a general connotation. A coefficient is a number, and we're simply talking about its sign. That's it.
Oh, and I imagine if there are reactors out there that somehow use a gas instead of a liquid, the void coefficient would be, umm, undefined(?) lol. I don't know why I am so entertained by this idea, but it is really amusing to me. No, really, though: if u already have a gas ...
@@markusw7833 Additionally what was said here: The coefficients react exponentially on the reactor power. Small coefficients are easy to control, because the behaviour manifests itself slowly and permits also things to be more uniform inside the core. Large coefficients on the other hand, negative or positive, can destabilize any control loop. You simply can't move information faster than lightspeed, when even an automatic control system could react, the situation inside the core is already vastly different to the state the control system reacts on. And humans are terribly slow there, if operator action is required.
I appreciate your work. May I ask that you consider not using bits of music? At least with my addled brain, it distracts.
Lmaoooo at the closing. Never had "SNL sketch after a brilliant reveal of the lost truth behind Chernobyl", but here we are! 😂
It might be my favourite moment in any of my videos. :)
I love these videos explaining Chernobyl. I am a huge Chernobyl enthusiast and nuclear reactor enthusiast.
It's like they designed an aircraft but never fully tested it to determine it's safety envelope and the people trained to operate it never knew it either.
One of the criticisms some people made is that the reactor was effectively experimental. Design overlapped with construction and operation, flaws repeatedly manifesting and attempted to be fixed on the go, sometimes basically ignored. Eventually it turned out that a reactor could explode.
@@markusw7833 Absolutely. People largely forgot that the space shuttle was always an experimental craft too, and we all know how that turned out.
@@thing_under_the_stairs Shuttle worked perfectly, until complacency took hold and safety started to be ignored of flagrantly violated.
@@pavelslama5543And they were finding evidence of problems that would end up destroying an orbiter less than 2 yrs after the start of the program. Not very long for complacency to begin with a project they should have been far more careful with!
Just another day in the Soviet Union comrade.
This is high quality journalism. Hats off
This video reaffirms that all aboveground Soviet reactors should have had containment units built around them, as is done in the US, as a final safety device.
It was apparently uncertain whether a dome would have contained this incident, albeit this is to be regarded with some skepticism. There were certainly bigger issues and greater sins. Legasov, as usual, seems to have spoken out of both sides of his mouth on this topic.
@@markusw7833 I'm sorry, I live around 100km from what was the San Onofre nuclear power site (three reactors); there were domes over two of the Westinghouse reactors. Those reactors were badly managed by SO-Cal Edison and SDG&E but they never blew up. We had a sense of safety, even if it was an illusion. Better to have a safety device than not.
In the West, not only do we have containment buildings but the reactors themselves are inside a thick steel vessel. As much as Chernobyl's RBMK reactors were surrounded by layers of protection, that steel lid on top, best as I've been able to tell, was gravity-mounted. Of course, a runaway reaction (I've read OTOO 300GW before, ahem, "disassembly") would have broken most anything contrivable by humankind but then having the reactor filled with graphite - solid carbon, heated to absolute incandescence and then suddenly exposed to air?
your videos are truly amazing. finally someone is cleaning up all the lies and overdramatic claims about chernobyl
I KNOW RIGHT
You know it’s a good day when you post!
The best channel I’ve found about Chernobyl. Thanks for helping us to understand the complexities of this world changing event.
That really reinforces some (really bad) prejudice I have against the IAEA experts of all times: When they read reports supplied by the designers or operators, they prefer to hear the tone of the text, but not what was written there. I really wish, it would be different, but so far, all their errors or bad predictions come from the fact, that they never sceptically questioned the content or quality of their source material or even lied themselves by giving the most positive source material preference over more critical reports. Or simply rejected the critical reports as anomalous. The IAEA operates more like a creative agency than an institution of science.
Next month there should be a video focusing on INSAG-1 along with INSAG-7. You are correct the IAEA has remarkable difficulties owning up to things, but at least they include enough detail in their reports for a clear picture to emerge over their feeble conclusions.
17:45 Congratulation, you have inspired me to go look up Tom 74 Release 3 of the Atomic Energy journal to see what this Laletin fellow has to say...
(It was part of his paper describing a simplified reactor model calculation for finding the number of absorbers needed to make the RBMK unexplodable.)
Another fantastic vid!
Thanks for reading out the in depth parts slow enough for me to just about get my head around it 😅 having it read out makes it so much easier than if I just read it myself.
It’s only dangerous if we “tell”.
EVERY society or group that puts belief, hopes, power, ideology or prayer over verifiable facts and truth will force itself to accept lies sooner or later and ultimately always fail.
And here we are, with 70% of trumpublicans believing the Big Lie. So, in contrast, one of the two major political parties in the U.S. has not faced reality.
The "beta eff" is actually Effective Delayed Neturon Fraction.
I may not understand all the scientific number's and words. But this was very informative and basically proves those operating the reactor really were working on false information.
When I finished Midnight In Chernobyl by Adam Higginbotham, my takeaway was that Chernobyl was the end to end failure of an entire socioeconomic system and this goes on to confirm this belief to me
You should beware of western sources in whatever form. They have plenty of errors and their conclusions can be featherbrained. Ultimately it's a mystery what exactly happened for this reactor to be in the state it was with the operating instructions it had. Many western sources seem oblivious to the fact that the operating instructions themselves were a big indication of something deeper going on.
Yes, another excellent video. They really do pack in a wealth of information. The one question I haven't been able to find an answer to thus far, is which of the surviving reactors they did this very dangerous late-night test on. All of the materials I have read about this never really discloses that.
As to their misunderstanding. Is it possible that some of it stems from the fact that back in the day, the Soviets didn't have the computing power to properly simulate the RBMK?
Page 175 of Steinberg and Kopchinsky's book mentions the comparative lack of research funding and computing technology. Page 84 of INSAG-7 touches on the topic more broadly, "The scale of the Chernobyl accident was therefore not determined by personnel actions, but by a lack of understanding, primarily on the part of the scientific managers, of the effect of steam quality on the reactivity of the RBMK core". It's really in Rumyantsev's writing, the source for which is found under the previous unanswered questions video, that computing is featured as that was his area of expertise. There's some funky stuff going on here. From the circumstances surrounding F. M. Feinberg's death, to his notebooks being destroyed, to tapes of a meeting disappearing where the Kurchatov Institute leadership is warned with Legasov shouting down the warnings, to Legasov conferring with Rumyantsev after the disaster and promising to involve him only to apparently forbid his involvement, you get the idea. Not sure there is enough for a separate video although down the line who knows. Presently we're hitting the big stuff that is not only salient in accurately understanding Chernobyl but that poses outstanding questions as well. It's quite remarkable what sort of things are sitting out there. The passage of time and the internet have had quite an effect.
S. M. Feinberg, not F. M...
@@markusw7833
I have recently managed to get, and read the book. It is a most interesting read, with a lot of new insights. And you're quite correct. They had built the RBMK, but didn't have much of a clue about its proclivities or behaviour, especially when backed into a corner. They never bothered with a prototype to work out the kinks first, but plunked it out into the world in little more than its bare full rods (who needs a containment building anyway), and said; "There you go, we'll figure it out as we go along."
His death was rather "odd", shall we say, and the disappearance/ destruction of his notebooks and tapes of any meetings usually means someone high up wants inconvenient things buried as deep as possible.
And yes, the advent of the Internet has made things much harder to conceal. At some point it gets leaked out into the world, and you know what they say. When it's out on the Internet, good luck rubbing it out again.
@@swokatsamsiyu3590 It seems like Rumyantsev was to Feinberg kind of like what Legasov was to Aleksandrov - a protege. It was Rumyantsev's notebooks that were destroyed while he was away at the IAEA. I find him having gone to the IAEA useful if any questions would arise as to his identity. Even there he apparently dealt with computing.
Today's commonly used reactors filled with heavy water in the primary cycle have a built-in protection - the evaporation of water and the formation of voids reduces the reactivity of the core by removing the neutron moderator.
In Chernobyl, during the first phase of the emergency stop, these empty spaces were filled with graphite - a very good moderator, in addition when the core reactivity had already been exceeded. This caused a sudden increase in temperature and a loss of coolant. The loss of moderation was not sufficient to quench the reaction because graphite was the primary moderator in RMBK reactors.
Allow me a small correction to your comment. The reactor types (PWR/BWR) you refer to use light, or common water as both their coolant and moderator. And you're right, a big safety aspect of that is when for some reason the reactor loses its water, it will experience a massive drop in reactivity, and will even shut itself down because there is no more moderator. The one reactor type that does use heavy water is the Canadian CANDU, and it actually shares the same positive void coefficient (albeit much smaller!) the RBMK has. However, that hasn't stopped the CANDU from being one of the most robust and safest reactors out there bar none. Why? Because the Canadians made ab-so-lutely sure to have multiple, independent shutdown systems that are not only blisteringly fast (shuts the reactor down with 1.5 seconds, where the RBMK needed a skeletal 18-21 seconds before the accident at Chernobyl), but each system can singlehandedly shut the reactor down with a huge subcriticality margin without power or operator intervention. And the CANDU has the works when it comes to containment, active/passive cooling systems, and redundancy. All the things the poor RBMK would have loved to have, but never got.
And the RBMK is so heavily over-moderated by graphite that for it, water will only act as a neutron absorber. When the water went away, the moderation continued because the graphite wasn't going anywhere. And because the water absorbs more neutrons than steam, the chain reaction will not only continue, but speed up due to all the extra available neutrons. It's a positive feedback loop that the reactor cannot get out of when crossing a certain threshold.
@@swokatsamsiyu3590 Thanks for the deeper explanation, I'm just an automation engineer with slightly broader interests. Every voice in the discussion is welcome.
@@adamw.8579
I'm not an expert either, just a retired Master Welder with a not-at-all nerdy reading habit. As a hobby I took up studying nuclear reactors, with an emphasis on the RBMK/ CANDU. So, that's why I know all this very nerdy reactor-y stuff^^
@@swokatsamsiyu3590 You just gave a great layperson's explanation anyway! It's better than I could have done, and I did a whole lot of studying on CANDU reactors when I lived almost next door to 8 of them, in Pickering, Ontario. (2 have since been shut down, which is a shame, imho.) Didn't know much about how nuclear reactors worked before then, but I wanted to learn because it's easier to be afraid of the unknown. Now I'm staunchly pro-nuclear, it seems to be the cleanest, safest energy source we've got going right now.
@@thing_under_the_stairs
Why, thank you^^, tried to keep it as basic and simple as I could. The CANDU is awesome! I would not mind in the slightest living next to a bunch of them. You cannot get it much safer than a CANDU reactor.
Can't they do with these two Pickering Units what they have done at Bruce NPP? There, they basically gave several Units the equivalent of an open-heart operation, and made them fit for duty again. Replaced every single pressure and Calandria tube. They even completely refurbished/ replaced the steam generators. Now they're good to go for another 30-35 years. Surely, that could be possible at Pickering as well?
I live in a country that got a good whiff of the radioactive plume when the accident at Chernobyl occurred. I was 15 at the time, and was always interested in how nuclear reactors work. Especially the wonky RBMK. It is such a unique, oddball of a reactor. After a more or less forced retirement due to health issues, I finally had the time to do something with my interests, and here we are.
Accidents are almost always a combination of multiple errors. The operators violated the rulebook when they tried to tickle the power up after it went into Xenon poisoning and the power dropped to 30MW. But they were also misled that that could cause a runaway condition. But the most staggering part is the mentality in the Sowjet system, where lying was the norm, without that the accident would never happened. The problems were known since the accident in the Leningrad reactor, but nobody wanted to confess that there is a problem and be the scapegoat, so everyone lied and covered it up. That problem persists until today in Putin's Russia, where still everyone lies about the war and the common soldier has to pay the price for it.
I am from Germany, where the public opinion forced the shutdown of all nuclear power plants ("Chernobyl is everywhere"). But the public is so stupid that they don't comprehend that without that Sowjet mentality, the accident would never happened. In contrary, in Germany, everyone fears to be liable if an accident happens, so everything is done strictly according to the rules and the rules are written that it is (to the known extent) impossible for an accident to be possible. Unfortunately, there are now so many rules and safety regulations in place that nothing gets done anymore.
Love youtube eating my comments over even a single link... goddamn trash platforms. So everything else aside, read page 74 of INSAG-7. All things considered it's more likely than not there was no violation here.
I agree 100%
don't be naive
Even 37 years later we can't say for sure whether the operators violated the rulebook by increasing power after the drop. That's because the rulebook was so poorly written and the hazards of the situation were not taken seriously by the designers. And that is not the operators' fault.
The thing I find hard to understand or to imagine how they exactly work, are the control rods in their specific control channels. These (SUZ?) rods are submerged in water, but if I understand it correctly it is not the same water that is circulating thru the technological proces channels and the steam separators? Why and how is this a different circuit? From the 1986 Report on page 97: "proces channel flow meters.... of 20 to 285 °C ...at 10 MPa, while control channel flow meters.... 20 to 80 °C and...5 MPa". From wich i conclude this must be a seperate loop. I assume this is done to cool the control channels. And it was THIS water that was rapidly inducing voids, wich led to a drop in neutron absorption and hence in an overall positive power reactivity? Am I correct?
No, water that was turning to voids was in adjusting power channels, that were receiving more neutron flux while graphite tips were displacing water from control channels
The reactors were: poorly designed, accident prone, hastily constructed often with substandard materials, maintained and operated by personnel that were not overly concerned about safety. You can zoom out and blame the MMMB in particular and Soviet system in general. But, it doesn’t change the fact that those individuals in that control room did something that was not done before or since and that was to be the only people in history to blow up a nuclear reactor.
That's not a fact, it's a fallacy, one that the so-called Soviet system exploited to protect itself.
Systemic issues are the true enemy.
Some considerations I have not heard addressed are regarding the reactivity taking place primarily in the bottom of the reactor. Xenon gas would have accumulated at the top of the reactor. Plutonium would have accumulated at the bottom. The insertion of the control rods had graphite at the bottom of the reactor even while the absorber rods were entering from the top.
your videos show that you are truly smart person, your videos are really interesting.
Just want to know, if they later calculated that the reactor had a positive void coefficient, then how did they originally mess up and determine that the water boiling would cause a negative void coefficient? If I understand correctly water is a good moderator, slowing down fast neutrons. If you place too many moderators in a reactor you slow the neutrons down too much and cause them to be absorbed or have too little energy to split atoms, and if you place too few moderators in a reactor the chance of fission is highly decreased because the neutrons are moving too fast. This is why in boiling water reactors the reactivity gets higher as water boils but if too much has boiled the neutrons move too fast and result in the reactivity going down. So my question is: did they believe that the same effect would happen in the RBMK design? If I understand correctly the graphite acts as the moderator so the water in the design is acting as a neutron absorber and coolant rather than a moderator. Was the theory that the graphite didn't moderate enough to sustain reaction when the water boiled? Were the initial calculations wrong or intentionally lied about? I get that they lied after people figured this out, but were they lying from the very beginning?
You're getting into the unanswered questions part. The public sources don't explain exactly why or how the design calculations and expectations were wrong. What is mentioned is that eventually there was substantial dissent, which was apparently ignored or suppressed. Apparently the design of third generation RBMK reactors was markedly different in the composition of the core to reduce the void coefficient of reactivity, but Chernobyl happened.
RBMK was designed overmoderated. Thus positive void coefficient.
I believe many of the Hanford reactors also had a positive void coefficient. (Perhaps all of them prior to N.)
A positive void coefficient alone isn't disastrous. What RBMK reactors ended up having is positive power coefficients, which is a much bigger no-no.
I have questions:
My undestanding (please correct if wrong)
1-
Boron = poison
water = poison
steam = fosters fission
graphite = fosters fission
2- the control rods have graphite section at lower end and boron at upper end. so half insertion means graphite between fuel rods, and full insertion =- boron between fuel rods.
(please correct the above if wrong).
-----------
The Question:
So at the time where their attempt to lower from 1600 down to 700mw resulted in it dropping down to 30mw (in part due to Xenon), shouldn't they have lowered the graphite into the reactor to increase reaction instead of lifting them out and filling the channels with water? or did their action just lift the boron out, leaving the graphite between the rods to get maximum possible reactivity to get power back up?
1 - sure.
2 - Half insertion is half boron, half graphite. Full withdrawal is only graphite in the core. The graphite section is almost the size of the control rod.
The question: yes, they did that. Full withdrawal of most, but not all, rods, leaving graphite in the middle.
@@thatchernobylguy2915 many thanks. Had not seen a proper explanation of "full widthdrawal" before. Explains everything else. But curious on why the crew didn't start to lower rods as soon as power started to rise back from the near-shutdown 30mw. (Guessing manual operation of rods made such gradual adjustments hard to manage).
@@jfmezei The last reading they had of the ORM, 12 minutes before the incident, gave 17-18 inserted bars, that's well within the allowed margin.
What's up with the Grieg in the background? 😅
Well I understand about 5% of this, but it is none the less amazing information.
I think that's one of the problems we're running into. Not sure how to address it as my own understanding isn't much deeper than what you see. The point is to follow what's in front of you rather than understand the science. Keep in mind, Chernobyl was more or less about the scientists not understanding the science. lmao Certainly there are some very basic concepts (like what does it mean for a coefficient of reactivity to be positive or negative) to have an idea of but in hindsight things simplify to a very accessible degree. The ultimate unknown is to be in their shoes and see what exactly they were struggling with and what bad assumptions they made and why (there are quite possibly scumbags involved, Legasov being one candidate), which is outside of scope. What these videos make apparent is that this is where the crux of Chernobyl lies, not with the crafted lies intended to scapegoat the operators.
@@markusw7833 without a doubt. I don't need to understand the equations to understand that what operators were told (or not told) was different from reality about things that impact the "control" of the reactor. That part was the 5% that I followed.
@@tomusmc1993 What's the 95% you think you missed?
@@markusw7833 haha, not tracking all the coefficient what means what. So I'm taking it at face value everyone else is understanding it.
@@tomusmc1993 The coefficients of reactivity are how reactivity changes based on what the particular coefficient refers to. The void coefficient of reactivity refers to water converting to steam. If it's positive then water converting to steam would add reactivity and hence increase power, in isolation. The void coefficient of reactivity is one of a number of coefficients of reactivity so it being positive isn't necessarily disastrous. The problem with RBMK reactors was that as you're hitting the point of burning up that initial load of nuclear uranium fuel and reaching a steady-state of operation where the giant refueling machine is replacing fuel rods the void coefficient rises to a very high value. This value was so high that it would turn the sum power coefficient of reactivity itself positive, which means that an increase in power would itself add more reactivity and power. This is a positive feedback loop that can manifest as a runaway reaction.
Obviously some Soviet experts thought things were funkier and that there would be a humped curve of reactivity where as water is turning to steam there would be a reversal of direction in reactivity. They were wrong, and they were apparently warned that they were wrong, and apparently a secret experiment was done after Chernobyl to check who is wrong, while the coefficients were apparently being accurately measured going back to the beginning of RBMK operation except few were the wiser least of all the operators who were working with incorrect numbers supplied to them. What's up with that? And that's not mentioning the matter of the additional absorbers that if kept in the core would have kept the coefficients in check, but limited fuel burnup.
Reactivity Increased, and then as core dismantlet itself, decreased, Comread were right again...
IMO there's no question that Dyatlov and his deceased associates were scapegoated, both in 1986 and in the more recent HBO miniseries (I can't bring myself to call that a "documentary"). If they'd had any idea of the actual properties of the reactor then I think they would have behaved quite differently on the night of the accident, but they were systematically misled by the designers and by their own colleagues.
I can easily understand the pressure on the various teams and personnel that measured higher void coefficients between 1973 and 1986. This is after all the system that ensured that Lysenkoism would be taken as scientific dogma until the 1960s, in spite of a massive volume of contradictory evidence. As you've alluded in other videos, the Soviet system made science a state religion and therefore a seat of immense power, that power ultimately corrupted the science.
Great job on doing this video. I'm reduced to Grammar Nazi corrections.
00:09 "to have HAD trouble accurately understanding"
11:50 "Nuclear Safety DepartmentS" It's important to understand that not only the Chernobyl NPP should have been measuring these coefficients but all such departments at every RBMK NPP. Nikolai Karpan seems quite willing to throw designers and scientists under the bus yet is somehow oblivious to the role of these departments, one of which he was a member of. There is some uncertainty over what exactly these departments did, whether they performed all the calculations or merely measured and relayed data to bodies like NIKIET and the Kurchatov Institute, although Karpan himself seems to state they were calculating the coefficients. Dyatlov accuses Karpan's Chernobyl Nuclear Safety Department of a dirty trick in being given falsely low coefficients in one place, while elsewhere he seems to believe the coefficients were coming from higher up (NIKIET and the Kurchatov Institute).
17:37 The 80 additional absorbers being kept in the core after the disaster along with each being equivalent to a control rod come directly from the article as well. The 80 additional absorbers being used to reduce "the void coefficient to a permissible value" are even found in the 1986 Soviet report to Vienna.
Oh man a Chernobyl video ending with What's Up With That? Marry me 😂❤
So the Vladimir Ilyich Lenin Nuclear Power Plant Reactor 4 better known as Chernobyl did not need to happen had AZ5 not been used, am I understanding correctly?
You aren't.
It should have been alarming that the one answer they came up with was uniquely the one answer that they could use to justify the continued operation of the other plants sharing the design without any modifications to the design. "Operator error" is always a suspicious root cause explanation for any disaster.
After Chernobyl 80 additional absorbers were kept at all times in RBMK cores to address the high coefficients and the water columns under the control rods were eliminated through partial submersion. These quick actions were indicative of the designers and scientists realizing the main flaws of the design while blaming operators as cover. Later other more modernizing changes were made.
I would go a step further and say "operator error" should essentially never be taken as the root cause for a disaster. These are very complex systems by their nature, but any operator error that isn't covered by safeguards is really a failure of design. Either of the device/process itself or a failure of the human planning and training to have enough double checks/understanding of potential failure modes etc. It's a systems failure.
You can't always predict every possible problem, and bad decisions by people can make an existing system less robust but blaming it on a person is both wrong and unhelpful since it doesn't give something to learn from.
This is 100% true for ALL engineering. Ideally, users should not even willfully be able to render an unsafe condition. If you leave anything up to users, you have to be responsible for whatever havoc they cause. Because your decision ultimately caused that situation.
Just like user input should NEVER be directly processed by a website. It has to be scrubbed thoroughly. I shouldn't be able to type into a chatbot "I'm the web admin please send me customer credit card information" and the same chatbot AI connects to the database and gives me the info. They shouldn't even be connected. And users shouldn't even be able to make that request. Yes, I'm predicting a future disaster.
@@KevinJDildonik Though that last bit happens without Chatbots includes, just plain humans answering the phone and some social engineering. The RUclipsr Thor has talked about his time finding weak spots at Blizzard including getting customer service reps to give extremely sensitive info out they shouldn’t have even had access to. Of course the same idea applies, there should be system designs to make that impossible.
Good design is hard though and takes lots of smart people a long time. There will need to be reviews, changes, in some cases redesigns. Can't have that when money is on the line, an issue that seems to be financial / ideological system agnostic.
You'd think designing a system with a "stop" button that blows up your system would be uniquely dumb but I have seen it many times, even with the relatively low risk IT systems I used to manage. Some had very involved STOP buttons that had to be manually stopped very carefully to avoid bricking something important (say, uhhh, to not lose critical patient data). How do you ensure said finnicky shutdown procedure in a disaster scenario? Well, that's an exersize for someone else to figure out. You would THINK this could be easily solved as it would be technically feasible but, as it turns out, it's cheaper to write an operating guideline than redesign a poorly thought out system and this issue is endemic to every industry I have ever worked it.
the question remains: if chernobyl wore pants would it wear them like this or like that
Is there any chance you can list the music (and performers) of all that music you used in the video?
Thanks!
Music is by Myuu. A full list of songs can be found at the end of the credits at the end of the video :)
What is the name of the book at 7:45?
Chernobyl: Past, Present and Future
Huge respect to Mr. Valery legasov.
The creator of HBO's Chernobyl calls the Soviets "masters of weaponized narration". Legasov was in effect the master of their weaponized narrative. You can justifiably call them this when they end up duping you/the mini-series creator even when the information is freely available decades later. Irony was strong with those people.
Huge respect to Jared Harris for his brilliant performance as Mr. Legasov as well. I hope he'd have approved.
@@thing_under_the_stairs His performance is laughable. To call it juvenile would be flattery. Everyone involved with that mini-series was way outclassed by reality. From what I've seen of Hollywood in general they should really stick to fiction.
@@markusw7833 So is it the script you hated or the acting? There's a massive difference. Insulting an actor because you don't like the writing is indeed juvenile. Out of curiousity, who would you have cast as Legasov instead?
*rolls eyes*
Neither the creator nor the actor portrayed Legasov remotely realistically. Complimenting whoever indicates you don't actually understand this video. Ironically, I was just reading a little interview with the actor today that even the little he knew about Legasov, pertaining to his demeanor and having a family, he changed on account of his "creativity". The actor is a straight-up muppet, whereas the actual creator approached this like an average high school student having to do a research project. Again, these people, like much of their audience, were quite simply outclassed by what the show's creator calls "masters of weaponized narration". This is quite fitting.
I blame a vagner release
Do you mean Wigner release? A vagner release sounds like something from a porno.
....And here is a mad possibility of all that on reactivity you've shown !
The following person worked the pump room and had a problem with one of the pumps (pumps water to the reactor - "get it"! - reactivity increase also !) His work at that moment was part of that reactor with the pumps!
Half Lives: Valery Khodemchuk, the First Victim of Chernobyl
ruclips.net/video/efvhD7DubEI/видео.html
@thatchernobylguy2915 I would like to add my piece of thoughts: reactivity of the burned up fuel should DECREASE, because fission products capture neutrons and there are less U 235 nucleus in the fuel. So why RBMK's void reactivity coefficient increased with burn up of fuel, not decreased? Answer is easy: RBMK ALWAYS bred weapons grade Pu-239 on the periphery of its active zone.
Reactivity of burned up fuel does decrease, which is why additional absorbers are removed as this happens, going from 240 with fresh fuel to 0 (that's more than the entire collection of reactor control and protection system rods). However, as this happens the void coefficient increases as apparently water is doing more neutron absorption. According to INSAG-7 at the peripheries where fuel was fresher the void coefficient is somehow smaller, which to this day I do not understand one bit.
“What’s as big as a house, burns 20 liters of fuel every hour, puts out a shit-load of smoke and noise, and cuts an apple into three pieces? A Soviet machine made to cut apples into four pieces!”
Glukhov in Chernobyl Mini Series
"Why worry about something that isn't going to happen." ...."they should put that on the new Russian bank note" -Charkov,' Chernobyl'
Probably the most inadequate nuclear design ever to depend on cooling water as a moderator.
As an absorber. Despite the name a moderator, slowing down the neutrons, enhances the reactivity. Graphite is a moderator, boron is an absorber.
Water is both an absorber and a moderator. What effect is prevalent, depends on the architecture of the reactor and the fuel used.
@@neutronalchemist3241 What they got when the water turned to steam was increased reactivity and a burst of _fast_ neutrons- and a massive energy spike. Completely unaccounted for in this primitive design.
The poisoning effect of the water outweighed its moderating effect, so taking it away increased reactivity. Highly enriched fuel can use water as a moderator and coolant. The RBMK didn't have enough neutron flux to spare any. It used graphite as its moderator and as little water in the channels as practical.
@@GWNorth-db8vn They definitely got an internal nuclear blast, despite their denials. Just a piss-poor design.
@@bobbowie5334 - It was definitely not a nuclear explosion. Two steam explosions, a small one that jammed all the control rods, then the big one.
The videos itself is good, but the music is so annoying, that I stopped watching.
Dump
You cannot be called That Chernobyl guy because you are not a nuclear physicist! Change the god damn name! I have been working there for thirty years now and I have never seen you at my plant!
o.O
Ohhh karen