Awesome video and presentation. Do you by chance have these slides posted somewhere? I am an ex-Navy nuke finishing my BS in Nuclear Engineering Technology and would love to have these slides to reference. @EthanChaleff
T-24 Hours- Power decreased from 3200MW to 1600MW Think you're a bit off for a reactor rated at 1000MW T-11 Hours - Power is held steady at 1600 MW Think that's a bit off too. Not to be totally pejorative but those are glaring errors especially for someone in any engineering discipline. Probably want to take a zero off all three of those numbers. The reactor's excursion wasn"t above its rated power until its final moments. Excellent image content.
Hmmm... It can't happen in the Western world. Three Mile Island. Fukushima. Brilliant comments by @johnedwards3621. Just one thing though: no "reality denial" going on in Western gov'ts...right? 'Nuff said.
I was just watching a video by someone who seemingly prides themselves on being a Chernobyl historian and spent the majority of the video trying to claim the HBO show was nothing more than more soviet propaganda aimed at discrediting the workers and refusing to acknowledge the inherent mechanical faults of the reactor design, by putting Prof. Lagasov on some kind of noble, truth seeker pedastal. Now im not saying they didnt do that but ill get to that part in a sec. Two things i hated, one of them came after watching many videos, including yours here, of nuclear engineers talking about the engineering aspect of what happened. The first thing i hated was that in this guy's video, he refused to even mention the parts of the show that directly addressed moments in which Prof. Lagasov lied about the whole thing being essentially caused by operator error. Never mentioned it. The second thing has to do with something he was fixated on, which is the line "because of the circumstances he created" referring to Dyatlov. He seemed to think that no matter what the operators did, that Chernobyl was going to happen, and judging from what i have seen you and about two dozen other nuclear engineers talk about, is that the operators absolute played a HUGE part in causing the accident. The fact that they continued with the test with such low power is absolutely insane. The fact that they didnt cancel it beforehand when they were told they couldnt lower power anymore before even making it to attempting the test with such low power is equally insane and the guy pretended that the hand they had in causing the accident wasnt anywhere near as impactful as the design of the reactor itself, which as far as i can understand, is wildly inaccurate.
The 2000 ton concrete lid was almost certainly sized with a safety factor of 10, which is the standard with anything that involves human safety (e.g. elevators, bridges, etc.), so they probably calculated that if all the water in the reactor was separated into hydrogen and oxygen and exploded, a 200 ton lid would have been sufficient to contain the force of the explosion. Hence the 10-times heavier 2000 ton lid. And yet the explosion lifted up the 2000 ton lid high in the air. The other problem is that Dyatlov stated that power was never raised above 200MW, as it was irrelevant to the safety test (unlike what the presenter says here), and at that power temperature was 350 C degree inside the reactor, far not enough to separate water into hydrogen and oxygen. Dyatlov was not a fool, neither were the others, and they could not explain what actually caused the explosion.
Why is it people cannot comprehend that the climate is always changing. It is just slow compared to the comprehension of the mind and our individually short time on this planet. Why would anybody think that the climate would never change through the eons? I hear people say oh it's hotter than it used to be. And usually these are people who work inside and have very limited or can control their exposure to the weather. I, having worked outside all my life know that it doesn't get out of a certain range of temperature. And you attribute climate change to anything man has done is folly. We do a whole lot more to control emissions than we ever have done. If you just look at the industrial age, say 1880s to the 1960s for example, they did very little to limit pollution. Surely what is going on now cannot compare. The Earth itself causes more "pollution" every year then we do. Look into how many active volcanoes there are on this planet and what they emit. What is it that people think we're going to do about natural gas? You can't plug up a cow's behind or even all the people? It's absurd, natural gas is a part of this planet and the planet releases it and always has and always will.
The climate changes over MILLENNIA not centuries. Your third sentence highlights your ignorance thats staring you right in the face. "Why would anyone think that the climate would never change through the eons?" Thats it. Climate changes OVER EONS. There was a period of time where it was constantly raining, known as the Carnian Pluvian Episode, where it rained, nonstop, across the entire planet, for about 1-2 million years. However, you are wrong to think that the climate ALWAYS changes. For the past 10,000 years, we have lived in what is called the Holocene, which is defined as a period on Earth's geological history as having a STABLE climate, where it hasnt changed more than a single degree of global average temperature for that entire 10,000 years, and we know this to be true because we can measure that stability. I live in Maine, which because of its position on the Atlantic Ocean Conveyor, has resulted in the Gulf of Maine to be warming faster than 99% of all other ocean waters. As a result, the climate of Maine itself is changing faster, and more drastically, than any other state in the US. The idea that "it doesnt get out of a certain range of temperature" is just factually not true, and observably false. These past few years in Maine have been its hottest. Its summer temperatures are happening in March and April now, instead of beginning in June and July. I mean its fucking hitting 80s in April which has never happened in my 30 years on this earth until like 5 years ago. As i said the climate has been stable for 10,000 years and there has been NO GEOLOGICAL activity to account for the drastic change in climate. We can measure the activity of volcanoes and we know how much stuff they spew into the atmosphere. We have sensors on satellites that literally tell us. Volcanoes are pretty stable in their activity, and as such, so is the amount of emissions they release. They release around a billion metric tons annually, while human activity in carbon dioxide alone, never mind considering methane yet, is more than 30 times that much. The thing that makes your ignorance so staggering, is you think only things like volcanoes do this. Yet, when humans emit the same molecules that volcanoes do, you pretend that when we do it it does nothing. Your comment about plugging up cow assholes also proves your ignorance and lack of understanding. It's the other end thats the problem. Its not cow farts, its cow burps that are the problem because of how many cows we have. Natural gas is a part of this planet but the idea that the planet releases it, always had, and always will, is again, factually incorrect. All that natural gas in IN THE FUCKING GROUND. So, how do you expect it releases it? Volcanoes? Well considering they are literally full of magma, it would explode if it came into contact with natural gas, and then, the pocket would no longer be there, so it would be kinda a one time thing. If you didnt know, volcanoes explode because of a build up of pressure, not a chemical reaction that would occur with magma hitting a pocket of natural gas. Earthquakes then? Do you know how often earthquakes end up cracking directly into pockets of natrual gas and releasing it into the atmosphere? Almost never. If natural gas pockets are disturbed and released as the result of an earthquake, it is almost always an earthquake resulting from human activities like fracking. Tornadoes and hurricanes dont alter the crust of the Earth in ways that can disturb pockets of natural gas. There are then no other natural, geological processes that cause the disturbance and release of pockets of natural gas. So no, the planet isnt always releasing them, hasnt always released them, and will not always be releasing them. The only other thing that gets those out of the ground, along with all other forms of pollutants, are due to humans. Period. End of story. I am an ecologist and climate scientist. You fundamentally do not know what you are talking about.
I found the presentation very difficult to understand simply because he speaks way too quickly. He's obviously very very excited and a huge nerd over this subject and wants to convey his enthusiasm but he needs to slow down.
3 simple questions: -Would steam act as moderator while water is poison? -If steam is transparent and does not slow down neutrons, how would these voids in water (or whole channel filled with steam) end up fostering increased fission? -When there is mention of the rods having been pulled up, does this refer to the combo of boron at top and graphite at bottom both being out of the zone where fuel rods interact, or only he boron portion being outside of that zone and graphite still very much in there?
After reading some more and watching other videos I have another question: Water is poison. Graphite increases fission, and Boron is big bad poison that kills reaction. The rods have portion of graphite at lower end and boron above it. If, at time they saw the reactor drop to 30 megawatts they wanted to bring the reactor back up, why would they remove the graphite rods to be replaced by water? Wouldn't that reduce reactivity even more? Trying to understand their thinking/logic in pulling back graphite rods in order to increase reactor activity.
Actually, destruction of reactor No.4 began even before performing of "Rundown of turbine " electrical test. About 2-3 minutes before start of test feed water was introduced into reactor and main circulation pumps were put in a full run decreasing inlet water temperature down to 160 C. At pressure of water of 70 bar , boiling temperature was about 270 C. Normally, fuel rods supposed to be cooling down only by boiling water with a rate of about 530 cal/g C. Because of introducing of not-boiling water into bottom of reactor, cooling effect on Zirconium case of fuel rods with a temperature of 2100 C was considerably reduced. While water was heating up to boiling point it was taking only (270-160)x1=110 cal/g C ( to increase temperature of 1g water for 1 C you need to spend 1 cal of heat ). So, deficit was about 420 cal/g C, causing overheating of Zirconium casing and its cracking. It was accompanied by hydrogen build up.
Is it known whether the 5 channels failed due to pressure or heat? When a channel flash boils, wouldn't the steam have ability to escape to the steam/water separator without pressure buildup? or does the connection between the channel and the steam/water separator have "full flow" or is there some constraint that would cause pressure buildup in the channel should the water evaporate at rate that is much high than designed for? Or was the constraint due to the graphite rods being lowered and thus obstructing flow of steam desperate to get out? Or would the channels have failed due to excess heat? What are the channels made of? I assume they need to be transparent so that neutrons from one rod can go annoy atoms in another rod and pass through the channel walls of each rod?
More questions: Say I order fuel rods from Acme Inc. From the time of manufacture, how come the rod doesn't go supercritical? Won't U-235 atoms emit neutrons that will hit other U-235 atoms in the same rod and result in 2 more neutrons being emitted every 0.0001 seconds? Or are neutrons that are unrestrained go too fast to annoy other atoms to cause the later to emit two neutrons?
Question: The uranium is encased in zirconium. Does zirconium also contain the iodine/Xenon produced during reaction or is it porous and iodine can escaoe and mix with water (and then decay into Xenon while in water/steam cycle) ?
A plane crash affects ~200 people and their families. A nuclear meltdown affects everyone. For decades. They're not comparable. People make mistakes, and about all we can do is put people in positions where their mistakes don't have global impact.
Thank you for this video. While I dont believe climate change is an imminent threat I commend you for your intellectual honesty. Anyone screaming that we are doomed from climate change while at the same time saying no to nuclear cannot be taken seriously. By your steadfast support of nuclear I can see you are a person actually looking for a solution to a problem and not wanting to slip in other government programs under the guise of climate measures. While I disagree with you, I respect you and your positions. What this world needs more of today is civil conversation and interactions between people that may disagree on things. What we often find is we agree on way more than we disagree on. I am a HUGE advocate of nuclear power as well and while our reasons may be different ultimately does it matter if we can team up on and agree on something these days?
You lost me a climate change..Another bs liberal talking point..The US economy is built around fossil fuel,the infrastructure isn't in place to switch over on a whim .When you get Russia,India,China to stop polluting than you get somewhere..We could stop using fossil overnight and it wouldn't change a damn thing,the biggest pollution sources are still operating
Neither Dyatlov nor the operators had been trained or taught WHY and TO WHAT EXTENT the native reactivity varies, rising quite a bit after power reductions, and obviously most dramatically when power is reduced quickly. They were well aware that you are not supposed to shutdown a reactor and quickly start it again. They were aware that PROCEDURE said you have to wait for a time, for native reactivity to come back down, before starting back up. But evidently they were never taught WHY. So when power accidently dropped too far, much farther than the level they were supposed to do the test at, Dyatlov insisted on powering back up. The operators resisted the idea. According to some Soviet sources, one of them even called another reactor and asked one of his peers, who told him that under NO circumstances were they allowed to immediately power back up a reactor that was basically shut down. Still Dyatlov ordered them to power back up. in every simulation and recreation you will see, they are all plenty nervous as they try this. This guy Ethan really does a great job of talking about so many of the factors that went into this accident. Ethan clearly knows his physics. I still feel Ethan could have emphasized even more, the importance of the concept of native reactivity. Basically, when all those fission products build up within the core, they add reactivity, but only slowly over time, and the neutrons flying around from the reactor operating break them down continuously, so a balance is reached. But when reactor power is reduced suddenly, then WAY less neutrons are flying around, so fission products are still building up, from decay products further decaying, but they are not being broken down nearly as fast, so there is a time lag in which any increase in power will result in a BIG increase, not just a small one. And Ethan did an excellent job of explaining void coefficients and other factors. So- what is to be done about this period of time where the core has this much higher reactivity? Well all you have to do is wait, usually about a day, before you start up again. It is ESSENTIAL for all operators to understand nuclear physics. If they don't, they may think, as DYATLOV thought, that this procedure is not that important- that they can bend the rules. We've all met rules in our lives that were stupid, or redundant, or simply bureaucratic. DYATLOV made the tragic assumption that he could ignore procedure. Had he been taught WHY this rule existed, he never would have made this decision.
This is very well done! I love Mr. Chaleff's balance of lay and technical perspective. I worked as a system engineer at a newer Boiling Water Reactor in the late 1990s (Clinton Power Station). We talked about Chernobyl and the RBMK design, but this was the first discussion of the physics involved that I've seen outside of the industry that makes sense. I agree completely with his conclusions related to why Chernobyl happened and why, as an engineering community, we must still maintain a rigorous focus. Nice work, sir! And a very important contribution!
If there's climate change, it's because of the big nuclear reactor in the sky - the sun. The temperature of the Earth is completely, 100%, due to the sun. Not carbon dioxide.
I just wanted to get some feed back to see if I have this correct. The power increase by the movement of the control rod attached graphite displacers from the center of the channels toward the bottom of the channels was not from the graphite, I believe graphite is only 2x better moderator than light water, the increase in power was caused by the graphite displacers displacing water in the bottom of the channel. This water had been acting as a neutron absorber. I believe light water is around 195x better neutron absorber than graphite. So the increase of reactivity in the bottom of the channels was not caused by the graphite displacers but by the loss of the neutron absorbing water in the bottom of the channels that those graphite displacers displaced.
Im elated that someone took the time to go into scientific detail about the physics involved with the reactor, because up until this point i didnt really get it
As far as the "routine test" goes, I was under the impression that it was <supposed> to be a routine test, but every time they tried it it had failed? I thought there were at least two attempts before the explosion, maybe more?
