I have watched dozens of videos on this subject and this video explained it the best of all! Great job making a complicated subject and making it understandable.

@amadeusjohansson

2 ай бұрын

kyle hill is better

@anubisokc8718

2 ай бұрын

@@amadeusjohansson Kyle is good and I follow him as well but as an instructor with 30 years experience this man simplifies a very complicated subject in such a way it is much less dense and easier to pay attention to and made it very understandable. I am sorry you felt it necessary to add your comment which is nothing but a negative troll remark looking to start an argument. Maybe SovCit videos are more your speed and target audience. I award you zero points as you have made a useless statement and everyone in this thread is now dumber. May god have mercy on your soul.

@glynnec2008

2 ай бұрын

I agree. The video by Illinois Energy Prof on the Chernobyl accident was very good, but this one is better.

Great explanation of why it went wrong. Much better and more detailed than any other explanation i have seen, heard, or read. Fukashina seems to be a simpler explanation for the disaster. But i thought that Chernobyl was simpler until your explanation. Please explain Fukashima, so I can learn the full, not-so-simple explanation. I think too many explainers for both situations either don't understand the technical complexities thenselves, or assume their audience wouldn't be interested in, or couldn't understand the technical details.

@moiraatkinson

2 ай бұрын

I couldn’t agree more with everything you’ve said. This is by far the best explanation I’ve heard of how the Chernobyl disaster occurred - and I’ve heard a lot on KZread. You clearly know your stuff, but you have that ability of good teachers, who can put information across in a way most people can understand. As far as I’m aware, the big difference between Fukushima and Chernobyl was that the “last line of defence” of the reactors at Fukushima prevented the core and the fission products from being released into the atmosphere. The different style of reactor had a smaller core, with a greater amount of concrete surrounding it and it held. I’d be interested in any nuclear type events you were to explain. This channel is a real find for me and I’ve subscribed to it.

@TerraPhysica

2 ай бұрын

"Please explain Fukashima" Sure I will, but there's much less physics and more psychology in it

If we could go back in time and take the knowledge of what we know now about it today, could it of been prevented back to 1986 .

Great video! So glad I’ve found your channel

That was the best explanation of any subject ever, let alone Chernobyl. And the first time I've understood why Xenon poisioning can conversely go on to increase the rate of reaction if you don't manage the 'removal' of it correctly. Thank you immensely :)

@MinSredMash

2 ай бұрын

Please don't listen to everything you watch on KZread. The idea that xenon burn-off initiated the power surge is an infamous myth, based on no evidence and apparently invented from whole clothe by uneducated commentators. The test was only 36 seconds long, and the power excursion much shorter. There could have been no meaningful changes in xenon concentrations in that time. If you are curious, I can provide an entire scientific paper published by Spanish and Japanese physicists which proves this. There are many other distortions of the facts in this video. Accurately explaining the accident requires rather more research than the channel's author has done.

Thank you for this video. Additional videos on Chernobyl (and Fukushima) are greatly desired. Thank You

Sadly this video repeats many of the same old myths that were debunked decades ago.

@litltoosee

2 ай бұрын

kindly explain Misc....

@MinSredMash

2 ай бұрын

@@litltoosee Stuck in an airport at the moment. Watch this space.

@MinSredMash

2 ай бұрын

@@litltoosee 11:47 The purpose of the test was not just to safeguard against a simple power outage. The reactor could already survive a blackout. The turbine rundown capability was only needed in the event of a design-basis accident: the rupture of an 800mm coolant pipe. In this case the extra voltage from the turbine would supply additional coolant to the emergency core cooling system via the feedwater pumps. 15:01 This part is backwards. Thanks to the long delay at 1600 MW, the peak of xenon poisoning had time to pass during the day on April 25th. If not for the unplanned postponement of the test, xenon poisoning would have been much greater! 16:09 It is enormously misleading and inaccurate to claim that the instructions "categorically" forbid restoring power after the drop to 30 MW. In fact the regulations were highly ambiguous, and even real-life RBMK operators continue to argue extensively over whether raising power was allowed or not. The fault here lies with the poor quality of the regulations and the instrumentation. 16:20 Your scenario ignores the fact that many types of reactor allow for immediately restarting a reactor after a scram. There is often a window where this is possible because the xenon has not had time to build up to critical levels. This was largely the case on April 26th, since they were only planning to operate for another half hour or so. 17:39 Akimov never "denied any accusations" from Dyatlov. This is a complete fabrication. On the other hand, Dyatlov stated that Akimov's (alleged) decision to raise the power was CORRECT, and that he would have given him the order to do so in any case. 18:15 You disregard the fact that the operators had no way of tracking the inserted rod worth in real time, because no instrument for this purpose existed. They were trained to regard this parameter as unrelated to safety, and only of relevance during periods of steady state operation. Again, the regulations were contradictory, likely because for the first years of RBMK operation, no such limit on control rod extraction existed at all. 18:40 There is no evidence that the personnel intended to run the test before scramming the reactor. Akimov stated that they intended to shut down as the test began, but a miscommunication led to a short delay. 19:47 The statement about an 18 second delay is only accurate for certain instruments. The instruments that monitored neutron multiplication in the reactor were still able to scram the reactor almost instantly in the event of a power surge. Power increased by only about 30 MW during the test. There was no power surge until pressing AZ-5 caused said surge to happen. 20:32 Virtually all eyewitnesses agree that Toptunov pressed the AZ-5 button. 21:20 Diagram is not to scale and quite misleading, because the water-filled space beneath each graphite section is only 1.2 meters tall, taking up the very bottom portion of the reactor. 25:55 The temperature coefficient of reactivity is NEGATIVE! Perhaps you meant the void coefficient and power coefficients? Or the graphite temperature coefficient? Those were all positive. 26:24 Low power operation was not limited or forbidden by the regulations. It is always shocking to see Soviet propaganda from 1987 on KZread in 2024. 27:13 Activating additional cooling pumps was an essential step of the test program and not a violation of any rules. They never "decided to reduce water intake" to the pumps either.

@pazsion

2 ай бұрын

the ammoint of deaths immediately and the years after until this very day. i estimate at 130,000

@pazsion

2 ай бұрын

both supervisors followed instructions, and orders from others offsite. no "orders" were given they were just going through the checklist... and instructions given to them. they would have shut it down if they had any indication of a problem, nothing indicates anything was wrong , warnings came late and nothing there could of handled a runaway reactor...

That was one of the best video's on the Chernobyl disaster. Still I think there was a spike in pressure when the steam was cut off from the Turbine Generator. After this point, there would be a relief valve open or operator opening a bypass circuit to take the steam and route it to the main condenser. (bypassing the Turbine). At this point the pressure would drop quickly, and considering the temperature of the water in the reactor core, the remaining cooling water would flash into steam. Then the positive void coefficient would cause the steam explosion.

Since i am a senios supervisor on a heavy duty chemical plant i am very interested into forensical analysis of process disturbance and the causes. Nuclear power plants are also hazardous systems it would be great to investigate more into this thematics...

Very interesting and well explained.

I would love if you can make a video about the Fukushima disaster. It would be really educational and cool to watch.

very good. subscribed.

I think a video about the benefits of the RBMK design would be quite helpful. Every discussion seems to focus on the end effect, large size leading to instability, and positive void coefficient - giving the impression that the USSR intentionally built the worst reactor it could. Not much is said about the relative efficiency of the design, its low enrichment requirements, potential for on-line refueling (ie changing rods without a complete shut down) and fairly high electrical power output (About twice what many UK reactors of a similar vintage could manage) get overlooked. WE need to consider the lessons about defense in depth and operator training - rather than rest assured it can't happen anywhere else.

At the 12:00 mark it talks about the experiment they were going to perform. It wasnt an experiment, it was a design feature that was never tested when the reactor was first built. But was never satisfactorily tested to work properly. Additionally, it seems to be an oversimplification, but the pumps are not necessarily provided power directly from the generator. They are provided power through the station service transformers which are supplied from the grid. The generator supplies power to the grid. So the pumps should always have power even when the generators are not running because the grid supplies them. The test was to provide proof that during a loss of bulk electric supply (LOBES aka no grid supply) the stored energy in the spinning generators can supply the pumps long enough to allow the giesels to start up and take over supplying the pumps. A LOBES event causes a reactor runback to a near zero power level as there is no grid to supply power into. The engineers and operators were extremely anxious to prove this feature worked because although LOBES are rare, they arent impossible and could lead to damage to the reactor if there was insufficient pump supplied water

“Reaction rate increase most rapidly in the lower part of the reactor. This is a ‘structural feature’ of RBMK reactor” I call that “shit design”

Cool! I listened same video in two languages: English and Russian. On same site!

@TerraPhysica

2 ай бұрын

They are both mine, here is just a translation

I would say that the "incident" happened due to several different things. In the USSR at this time most people were "given" a job, meaning they gave you a job you had to do and it had almost nothing to do with who you are. So you end up with a lot of people not interested in nuclear power running their nuclear reactors. So these people arent interested in it so they dont learn important things about it just by being them. Secondly in the USSR in order to climb ranks you had to take risks and showing good results at the same time. Since it was the person that actually showed the results that could climb ranks, risks were seen as a net positive for the person. If nothing major happened you could easily hide it and do it again, until you got the results you wanted and thus climb ranks. Third the design of the reactor was aimed at "doing it as cheap as possible" instead of the wests "lets be careful" design. For example the RBMK reactors could use uranium that was hardly enriched at all due to very low neutron capture, while the west went with water that does need higher enrichment of the uranium to operate due to neutron capture of the water. So the wests reactors decreases in reactivity with heat as the wests reactors uses water to slow the neutrons down. While in the east the opposite is true. So why did it happen, personnel that arent interested in nuclear power so they dont understand how it all works, conjoined with heavy risk taking by the higher ups and a bad design. All leading up to the horrible accident.

@MrZorbatron

2 ай бұрын

To the point of cheapness being a target in the design, the RBMK design can use spent PWR fuel for a portion of its fuel load, further depressing operating costs. Now, this heavily irradiated fuel is obviously very cheap, but it brings with it a large list of safety concerns. I am not sure how often this capability was actually used. CANDU reactors, due to high neutron efficiency, are also capable of this, but the ability has not been used beyond original testing.

@misc6102

2 ай бұрын

​@@MrZorbatronno RBMK reactor ever used spent PWR fuel. Period.

@misc6102

2 ай бұрын

Totally ridiculous to suggest that the personnel at Chernobyl were "not interested" in nuclear reactors. Dyatlov himself fought tooth and nail to get his job. Nuclear energy was his raisson d'etre.

@MrZorbatron

2 ай бұрын

@@misc6102 I didn't think that it was done. I know that it was intended to be possible to somehow use VVER fuel in it. I doubt the fuel assemblies themselves are compatible, so I'm guessing the elements would have been robotically assembled into new fuel assemblies somehow. I have no idea. I had read that it was never done operationally. I didn't know if that meant it was never tried at all, or that it was never done beyond testing. The same actually goes for Canadian power plants. They never actually used spent fuel from other designs, though they originally touted the capability.

@MinSredMash

2 ай бұрын

@@MrZorbatron Cheers. The RBMK had a number of such interesting unrealized capabilities. In theory it could even run on natural uranium, like the CANDU. But this would have been highly undesirable in practice. And as many have heard, it could have been repurposed to breed weapons grade plutonium, even though this capability was never needed.

A somewhat good comparison to what happened at Chernobyl I think is : imagine that you are trying to start a sour engine by holding the throttle at max while attempting to start it repeated times over and over again. If and when the fuel then finally starts to ignite in the cylinder, even a little, the excess fuel in the cylinder is then quickly burned off and the engine goes WROOOOOOOOOOOOOM! unti it rips itself to pieces from overspeed. That is basically what happened with this reactor a bit simplified : It got sour (Xenon 137 poisoning), full throttle is applied (all rods are pulled out), xenon burnoff occurs while the reactor is still being held at full throttle and it thus suddeny rushes out of control with the graphite tips on the control rods working sort of as a nitro boost to everything. AZ 5 = Applying the nitro to the reactor.

@MinSredMash

2 ай бұрын

Xenon burn-off is a myth. Do you want to read the scientific paper that proves it? Also your analogy overlooks the fact that AZ-5 is literally the emergency break and engine cutoff.

What was the purpose of the graphite tips on the control rods? It is widely stated to be water displacement but wouldn't an all boron control rod also displace the water when inserted? And if we subscribe to the theory that the Russian's goal was to build reactors as cheaply as possible, why go to the expense of this dual element control rod in the first place? AFAIK, no reactor technology other than RBMK has these graphite tipped control rods? Why?

I have watched a 100's+videos,documents,and movies(yes including HBO miniserie and russian černobil 1986 2022,this is the VERY BEST Explained ,so that every person can easy cought what happened,BRAVO 5 STAR-take that hbo, P.S. Dyatlov asked to raise the power and Akimov pressed AZ-5 A3-5

Positive void coefficient.

go and see that chernobyl guy he made a much better video about it this is not that true

It should be noted that that Russian reactor design was a copy of US Hanford reactors from the 1940's Hanford reactors built during the Manhattan Project. Obsolete in the non Russian world for decades and dangerous. It also uses the boiling water design which leads to radioactive turbines and other plant equipment. The pressurized water design avoids this. Caron also burns. US reactor operators are also highly selected and undergo long training before being allowed to operate a reactor. Mainly are from the US Navy reactor program where operators are required to have 115 IQ or higher and undergo several years of training. That is with a higher than 50 percent failure rate. My class graduated fewer than a third of the students.

@MrZorbatron

2 ай бұрын

There are significant differences between the RBMK and HEW reactors. In fact as far as I can see, the only similarities are that the reactors are both graphite moderated and water-cooled. The rest of the design philosophy differs substantially.

@misc6102

2 ай бұрын

What fairy tales you tell. The RBMK isn't a " copy" of a Hanford reactor any more than the Hanford reactors are clones of the Chicago pile. Ridiculous comparison. Also, if anything Soviet educational requirements for reactor operators were higher than those in the U.S., where strict procedures meant that some operators did not even need a college degree. Furthermore, the Soviet industry was also full of veterans from their own nuclear navy.

How are you meant to control a nuclear reactor with an 18 second lag? That can't be true. No sane reason why sensor data would take 18 seconds to travel along a wire into a display.

@isbestlizard

2 ай бұрын

When I turn on my geiger counter, it doesn't tell me the radiation level 18 seconds ago. My car engine temperature gauge doesn't tell me the temperature 18 seconds ago.

@ximalas

2 ай бұрын

I assume a “slow” computer is placed in between, though I might be wrong.

@MinSredMash

2 ай бұрын

It's not entirely true. Certain instruments like the power level display can have a very long lag time. But the neutron sensors operate virtually instantaneously, so if reactivity was surging above normal limits, the reactor operator would know about it immediately. This video is highly inaccurate at multiple points, like virtually every other example on KZread. There was no power surge in the reactor until after they pressed AZ-5.

@TerraPhysica

2 ай бұрын

Please remember that we are talking about technology, that was used 50 years ago. Computers were not that fast that days, and calculations were pretty tough. I'm not quite certain, but I think in US and other countries numbers was almost the same (btw, it would be interesting to now that)

@johnpekkala6941

2 ай бұрын

I heard from another description of the accident that the sensors monitoring the reactor power and temperature were placed only in the middle part of the core and so there was no direct monitoring of either the lower or upper regions of the reactor wich lead to the increased activity in the lower part being hidden to the operators until it was too late. They could not see that the lower region was heating up rapidly compared to the rest of the core due to lack of sensors in that particular area.

Wow, they’re already trying to capitalize on That Chernobyl Guy with AI. This is flat out AI copy cat shit

Because the Russian messed up thsts why 😊

And also some people were drunk in the work and in saving works but i saw in othet documetary that doctors in moscow helped these pacients were shocked that they were almost imune to radiation

@TerraPhysica

2 ай бұрын

You are very wrong about that. HBO series do a bad job in that sense

Well clearly they forgot to reverse the polarity of the neutron flow.

@litltoosee

2 ай бұрын

please explain Jan...

It didn't EXPLODE. Nice click bait though.

@matthewmaldonado33

Ай бұрын

Sorry to tell you it did tho

I have watched a 100's+videos,documents,and movies(yes including HBO miniserie and russian černobil 1986 2022,this is the VERY BEST Explained ,so that every person can easy cought what happened,BRAVO 5 STAR-take that hbo, P.S. Dyatlov asked to raise the power and Akimov pressed AZ-5 A3-5