26. Chernobyl - How It Happened

[@mitocw]

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[@badmintongo4832]

Can't enter form, any way to fix?

[@rawbebaba]

This was awesome thanks for posting this, I don't know shit about this but the teacher was able to present it in a way I could digest

[@rawbebaba]

@@MinSredMash I mean to be fair, we all grew up with that propaganda. Make no mistake, the soviets did do some fucked up shit leading up to, and after the incident, but I mean look how we handled covid in america, I'd say it was our Chernobyl, there's this refusal to admit, that big institutions, big systems lie and cover things up, even ours, and it has very little to do with systems of organizing economics

[@JC-lu4se]

@@rawbebaba Can't you write something without being a potty mouth? Get some class.

[@th.h.4947]

Cameron James Think that: Well if you would be the General Secretary of the Sowjet Union, former head of KGB and you learn to know by western satellites images, sent over the red wires from the US and Sweden, that your "NukePlant" blew up with seismic eruption already three days ago, the special f-word would be exceptionally understandable...but I don't know the Russian equivalent translation. But as such the omertà-system is definitely proved to be mad as a psychiatric hospital!

[@davedavids9619]

Am absolutely not on the level of these students, but can still understand and follow this lecture. This professor is superb in making a difficult subject understandable. Thanks for posting this video.

[@Filmkid3000]

Yes!

[@npxmnpxm]

I agree. And I think there's an important lesson for younger students in all of that: don't be turned off by what others may dismiss as a "hard" subject. Something like nuclear physics could be your calling. Pursue it, and the world might just thank you for it one day.

[@topform4665]

Excellent lecture

[@JC-lu4se]

Go and look at some of the other lectures such as lectures 21-23. Those will blow your mind.

[@jimstepan3038]

👍🏻 X 💯💥

[@kgucmen]

I am thrilled by the simplicity and understandability of this class.. This teacher made me think about returning to school, with my age of 50... Hats off to you. Mr. Michael Short... If I only had 1 or 2 teachers like you, I would have been the best student of the class..

[@Howtragicforyou]

Illinois energy prof is also pretty damn good at the down to earth education

[@Falcrist]

I went back to university in my 30s, and it was an extremely rewarding experience. It wasn't like when I was fresh out of high school at all. It was only an ok-ish state university, and I got my BSEE. I had an absolute blast as I rediscovered my love of learning. Unironically 9/10 as in nearly perfect. Highly recommended experience. If you go back, please consider updating us here. :)

[@bf1255]

@@Falcrist same story, same age, same positive experience.

[@doncorleon9]

@@Falcrist Indeed even Jordan Peterson(or was it N D Tyson) mentioned it is such a disservice to be made to think University education ends that early fresh off high school. My uni experience then was not bad but I believe now in my 30's my approach to learning and locking on to the objectives of study are much better honed than when I was a wee lad. The internet sure is the best thing since sliced bread.

[@paulsto6516]

@cops and govern ment are gangstalkers TLDR;

[@johnwaldeck2748]

This guy is excellent. The students taking his class are really lucky to have such a responsive, alert, intelligent person to present the issue - and answer the questions coming from it.

[@Medved-Yarik]

That's why he teaches at MIT.

[@forthehomies7043]

The students worked very hard to get accepted into MIT. Professors like this are their reward!

[@christopherkurylo8406]

I'm an engineer and am very impressed and humbled by how well spoken and clear this professor is with such a difficult subject.

[@adamjetson5536]

Are you a little jealous?

[@harryabbott5503]

@@adamjetson5536 what’s he jealous about? Picking an arguement on someone for no reason?

[@joedirt3226]

the moment he invoked janis, he revoked his credibility

[@rasmushochreuter2102]

@@joedirt3226 Revoked his credibility?

[@fitfirst4468]

I too am an engineer and I think Christopher Kurylo is a bum.

[@Tocsin-Bang]

I'm 73 years old. I spent most of my working life teaching science. This class makes me want to go back to school. I used to explode hydrogen and oxygen when I taught chemical reactivity, I used to always warn my colleagues when I was going to do it, one time the Head of Department didn't listen and the bang made her fall of the steps she was using to put up a poster!

[@servit0r]

nice

[@tntstorms7969]

Imagine the mega explosion when the oceans on the earth were made especially if the chemical reaction of making one cup of water creates a loud explosion. Luckily no one was here to hear it. Ha ha.

[@normaneustice1112]

I would like to thank MIT for this superb presentation. It has brought closure to my wife's passing nearly a year ago from thyroid & bowel cancer. She was living in Sofia Bulgaria at the time of the disaster. I remember her telling me that she accidentally ingested rain water that tasted metallic & bitter. First her thyroid failed no matter how much iodine she took to correct the issue it got worse, then a few years ago, no matter how much food she ate she lost weight & strength, now I now why.. Again Thank you for bringing closure to a painful situation.

[@amir-jg4zy]

I'm glad you got closure Norman. This was a fascinating lecture.

[@normaneustice1112]

@@amir-jg4zy Thank you for your comment, I knew the where & the when, it was the how & the why that I struggled with. This lecture told me everything I needed to know & it has given me closure. I am so grateful to MIT for explaining a very complex issue in such a simple way that a layman such as myself can understand the "mechanics " of nuclear power. I don't blame the Russians or Ukrainians for what happened to my wife, that's a battle best fought by scientists not politicians & for me the battle is now over I have my answers.

[@SolamenteVees]

So sorry for your loss.

[@MrDukeus]

another Chernobyl brewing in Ukraine

[@oshixxxx]

I am sorry for your loss. I agree, that this lecture is the best one, to this date, about the chernobyl accident. Just a comment about your wifes cancer, and chernobyl. If you lived near the power plant at the moment of the accident then sure, the risk of cancer is increased. I work at the ER, (emergency room), so I see at an almos daily basis, patients with some kind of cancer. First of all, I feel sorry for crabs ,that are named after this terrible disease, that takes lives way to early. Alright, my bad humor part is over. Second thing about the subject, the risk of getting cancer after exposure to high doses of radiation is simply put an calculated risk. Exposed to this lvl=the risk % of getting extra cancer in your life. Just making up numbers for this, but instead of the normal risk of getting some kind of cancer in your life is 20%, after exposure, it will be 40%. What I tried to say, is that cancer is an very common disease these days, and a great sadness falls on my mind, when I see folks under 50, that has some sort of the disease. About one in ten, have either had cancer, or are fighting it atm, of the ppl who comes to the ER. Multiple cancers, that your wife had tho, is an whole other subject. If one of the cancers arent an metastases of the origin cancer, then I would say that it is probable that the cause of the cancer is an environmental factor. The most exposed organs after an nuclear accident are the thyroid, lungs and the intestines, so it makes sense that the accident probably is the cause of these cases of cancer. Im sorry for your loss. The most painful with the cancer patients is that they are often open about their disease, mostly almost healthy, and tell us about their health openly. And yet, we can do nothing to help them. Their only hope is chemotherapy and luck, that the treatment is effective. Every cast we make feels like we cured someone, but cancer, and sending them of to the next departmen at the hospital, makes me feel hollow inside. I went to the xray with one of my patients, to get an thorax image of his chest. I was in the control room of the xray, and I saw the images of his lungs. Normally the images are somewhat grayish and you can't see much, but his lungs were filled, with clumps, tumors everywhere, and in both sides, about 10-15 different tumors. The biggest pain was that I could not tell him about the findings, im no radiologists, so I was not sure what these clumps meant, but quite sure they were not meant to be there. (I did get that his days were numbered),

[@chinruiz4113]

Knowing the science is one thing, but teaching it well is a completely different beast. The professor tamed both

[@covidhoax7646]

This is mostly engineering, not science.

[@KailyKail]

If you can’t teach something well, it’s because you don’t know the material well enough. Those who are great teachers know the content so intimately, they can break it down so such a simplistic level that anyone can understand it.

[@covidhoax7646]

@@KailyKail correct.

[@joshhead9368]

@@KailyKail patience is also very important when teaching. You can know all the material but if you have no patience to do deal with the people trying to grasp the subject. You're hopeless as an instructor

[@Cbd_7ohm]

Learning is way harder than teaching what you already know. I get what you mean but if you already know how to refine gold from ore, it isn't going to be THAT hard to teach etc.

[@PaulLundgren1970]

I have no background in nuclear (or any other) physics, just wanted to say I appreciate a person with extensive knowledge speaking from a position of expertise and legitimacy. Very well done, professor.

[@sabishiihito]

@tsia did you ever wake up or get treatment for being disconnected from reality?

[@francisbaconstrip7224]

The reality is everything is a lie and either you’re a fool for trusting Luciferian Freemasons or you are one.

[@avincombat939]

I watched the mini-series about Chernobyl, found this, and ended up going through the whole course. Thank you for uploading!

[@TheGrimravager]

Graduated in nuclear physics, and not once had the pleasure of having a lecture dedicated to chernobyl. Guess this makes up for it, thank you very much!

[@IntrusiveThot420]

Jesus, and here I am doing heat transfer for mech eng and sweating 😂 nah but i wouldn't have it any other way. Even just undergrad is expanding my perception of every random object we take for granted in our daily lives.

[@jacobslapinski3710]

NERD!!!

[@iyok050106]

@@IntrusiveThot420 Also Mech Eng here. How hard is heat transfer?

[@Bollibompa]

@@iyok050106 No course is "hard" per definition. The variance comes in terms of the lecturer and the way they assess your knowledge throughout as part of the curriculum. One could argue that since it's an undergraduate course and on a basic level it should be "easy" but this is not always the case. The only way to truly answer your question requires knowledge about your interests and the focus, the pace and the breadth of the curriculum. Heat transfer can be very theoretical and focus on mathematical derivations, advanced modeling, numerical analysis, finite element solution sets etc. Or it could just be based on purely empirical models and real-world applications.

[@iyok050106]

@@Bollibompa I didn't expect a lengthy answer. Thank you!

[@Matisyahuwu]

I love when a teacher says “let’s just wind down a bit since your other classes are going full throttle”

[@JustGoodGames.]

That made me feel such relief and I'm not even in his class lol.

[@Tony-pv4pe]

i think it's also a clever analogy foreshadowing the lecture, the experiment of winding down the reactor, but the RBMK design causing the power to increase.

[@twelvecatsinatrenchcoat]

@@JustGoodGames. Can you imagine what like 14 credits worth of classes going "full throttle" at MIT must look like? In a Physics degree? That sounds like your brain would just drip out of your ear like a goo.

[@kender1412]

@@twelvecatsinatrenchcoat -- If this class is any indication, very informative but not horribly difficult. One of the things I noticed going from Maricopa Community Colleges to ASU was that the level of actual professors' efforts in education went down through the floor at the same rate as my tuition went through the roof. I would have loved to have this professor in my university experience.

[@mr.p416]

@JET MECH This couldn't be further from the truth, as someone who went to one of these schools. It depends highly on the school and their policies. Google grade deflation.

[@owenwilliams9582]

A really good explanation of the Chernobyl event. I was working at a nuclear site in the UK, at the time. We had just started our evening shift at 14:00 on a Friday i think, one of the guys had some work to do in the Reactor equipment building, he entered the building through and then realised that he had forgotten some tools, he decided to go straight out, and had to go through the exit radiation monitors, which alarmed to high haven one they started to monitor him. The radiation protection engineer was called, and he explained that he had just come in from outside and had not been in any contamination areas within the building . We had just had a shower of rain and so decided to use portable radiation detectors outside, to our horror, we were having reading 200 - 300 counts/sec... this was baffling to us at the time as to where i the contamination had come from, we eventually found out the following day, i think, what had occurred at Chernobyl. Reactor Safety systems are designed to keep us all safe, shame they by-passed them, but they guys who tried so valiantly to contain the contamination spread at the time were real heroes.

[@raven4k998]

how did it explode it was like a steam fart that blew the reactor open it was an amazing site to watch just before the radiation kills you

[@Zero_Point_Energy1]

That was the most interesting and relevant KZbin comment I’ve read in a long time.

[@pitpatify]

Same happened in Germany. My father was the radiation protection responsible on duty in a nuclear power plant when they had workers coming in from Austria or Bavaria, where they have had rain. As the workers entered the plant, the contamination protection was activated and automatically closed the turnstile.

[@kevindodd5739]

R😊😊😮😅😊😊😊

[@GamingHelp]

owenwilliams9582: The counters you had that you mentioned were detecting 200 to 300 counts per second, what would the normal background measure with the same instrument?

[@timandshannon03]

Great lecture. I am a simple blue collar guy who is fascinated with subject matters that are usually well above my pay grade. As a craver of knowledge, this lecture was interesting, and he keeps your attention. I wish I would have had a few teachers like this.

[@rollingslothmachine3431]

Don't let your job description singlehandedly define who or what you are. If you crave more knowledge then needed for what you do for work, then that's a part of yourself too.

[@noelht1]

Rusty. I concur with what Rolling Sloth says. We are never too old to learn. I similarly had a lifelong desire to know more about the universe and at the age of 35 I did something about it. There will be adult evening classes at your local university that cost little money. They will start at a level you find easy and move on from there. You’ll finally be able to get the answers to your questions and you’ll love the experience. It’s a different and positive environment to be in, and you can take that journey as far as you want to go. My friend, go and do it. 😀

[@maciej.ratajczak]

"I wish I would have had a few teachers like this" is grammatically incorrect. It should be "I wish I had had a few teachers like this". [This is a hypothetical/unreal situation in the past, so it requires 3rd Conditional structures (eg. If I had had better teachers, I would have gotten better grades.] There are two parts to a conditional sentence: an if-clause (protasis) and a main clause (apodosis). What you did, Rusty, is you combined the protasis and the apodosis, which is grammatically incorrect, but very common in American English. I'd say almost half of Americans do it.

[@fahimp3]

@@maciej.ratajczak Chill out grammar-nazi. We all know what he meant...

[@Jabarri74]

@@maciej.ratajczak Is calling someone out for a mistake on their grammar an oxymoron as the sentence is questioning the teaching they received? Seems kinda hypocritical to me as you are far more educated than most of us in the English language

[@bobtheman1]

47:31 - "When they [reporters] only tell the half of the story that gets them viewers, and don't tell the half of the story to complete the story, and tell you, 'should you be afraid or not?' Because unfortunately fear brings viewers. This is the problem with the media today: With a half-truth and with a half story you can incite real panic over non-physical issues that may not actually exist." Haunting words.

[@diji5071]

Par for the course.

[@pgame20]

Never more poignant than now 😔

[@rudi_ghuliani]

And that's why I have IOSAT tablets

[@RawkL0bster]

Covid comes to mind. Stoke the fire, regardless of the danger or not, and your news company's stocks go up.

[@Just.A.T-Rex]

Media always you mean

[@wreckim]

That any human can get to this level of understanding is quite impressive, but that you can teach and entertain the mind with your talents as an instructor is quite rare and motivating to me as a 4th grade teacher. I dreamed of getting to this kind of level of knowledge, and failed. But this lecture motivates me to have my students accomplish what I could not. What a great post, thanks for the OCW, MIT.

[@kellygarland63]

Totally engaging lecture as a layperson. I could actually understand this.

[@mangos2888]

Students don't get to his class without doing well in yours so do not feel bad. We need good elementary teachers!

[@ciel1083]

You can't even teach 4th grade as good as this? You must have the intellectual ability of a kindergartner.

[@heresy3573]

🤣 you are being taught information provided from a Enemy State. If yall are as smart as you make yourself out to be, you will understand what I mean

[@shyshka_]

@@heresy3573 go back to pubg kid, nobody understands your psycho tin foil hat thoughts

[@gfsm]

This is one of the videos from MIT that makes me think about how bad my lectures really are... Concretions MIT and the professor for sharing this great content with the humanity

[@NazriB]

Lies again? Champions League

[@thekinginyellow1744]

You can only fail if you quit. Keep at it. You never know if the next Einstein is coming through your class!

[@luke53285]

I love this professor. He teaches clearly and concisely and doesn't mix words. He is very direct with ehat he sees to be the real problems with this area of study. We need a lot more educators like him.

[@johnwattdotca]

Why is he teaching about Russia? Why not Three Mile Island, the first meltdown that was in America?

[@saarbrooklynrider2277]

@@johnwattdotca Chernobyl NPP isn't in Russia. Maybe you should listen to his lecture, you might learn a thing or two :@

[@johnwattdotca]

@@saarbrooklynrider2277 I remember when Chernobyl happened. All American media described it as a Russian meltdown. Why hasn't a soap opera been made about Three Mile Island?

[@Banana_Cognac]

@@johnwattdotca Because not a whole lot happened at 3 mile island. It was still interesting, but it was a small accident that barely affected the building the reactor was housed. Chernobyl was a disaster that affected multiple countries and countless lives. The 3 mile island accident was more so a tool for the misinformed to spread their hate/irational fear for Nuclear power. However, if you're looking for a video about it, Kyle Hill did a good one.

[@johnwattdotca]

@@Banana_Cognac Having a fear of nuclear power is a sane attitude, if you have one. The reason mankind gets played so easily by electronic technology is because you can't see electricity. If you are deeply educated about electricity you would also fear AC/DC. Three Mile Island was never supposed to happen. I'm happy to see you admit it did.

[@JetPackDino]

This professor is a rock star, and I wish I could have been in the front row. Nicely done. And I loved one of the last things he said. "The data isn't out yet. Hopefully it never will be." I kind of think that people who are very intelligent in these STEM areas have a reputation for being uncaring or emotionless but what he said, to me, is the evidence of real understanding and humanity. It was just phrased in his way. I thought it was kind of poetic.

[@one8576]

You are the one who doesn't have a real understanding of these scientists and professors. He's just saying that for the class, but in his heart and actions, he really wishes the truth could be discovered about the effects of radiation.

[@Mornathel]

@@one8576 there’s a difference between wanting to know information and learn the truth and understanding the terrible implications of what that means and hoping it doesn’t happen.

[@one8576]

@@Mornathel There's a difference between just understanding the implications, and being alright with them.

[@jongyon7192p]

@@one8576 that's literally what they said, so I guess you agree they hope it never happens

[@sarahgondos]

I've been searching for a WHILE to find someone who could explain this too me in a way that I understood. If I'm being honest, MIT was the last place I thought I'd be able to learn this because I'm not on that level of education. This teacher was BORN to teach. He breaks it down in such a way that anyone could learn. I feel confident that I could explain this to someone else.

[@nathanwahl9224]

I fully agree, and I'm the opposite; I used to teach this event to the people that operate a nuclear plant in the US. This is very well done from my perspective also!!!

[@markrobertdevison1227]

I think if I watched this a few times, I could as well. I'm super happy to have found this video and watched it.

[@GeckoForReal]

Just because it's an ivy league university does not imply that the topics must in any way be hard. Just difficult and expensive to get accepted there I guess

[@matthewgrasso7167]

I’m impressed that at 20 minutes in to the student’s question he had the confidence to answer “I’m not sure.”

[@NewWesternFront]

i was impressed by that too. it's very important for a professor to be able to say that. I keep asking questions to my new chem professor and she leads me down a confusing path of, in retrospect, unrelated tangent

[@leonkriner3744]

My physics and math abilities have faded away since school and college, but I was mesmerized by the lecture. Very well presented and lots of aspects covered.

[@masterscubaman]

I worked at Leningrad NPP after the accident upgrading the SKALA system for 3 neutron flux cals. This lecture although there are some minor flaws is really good - there is a reactivity balance model that might have enhanced it further by showing Niles vs time for changing neutron energy populations, Xn135 conc and rod position. They also broke 6 operating rules leading up to the test not just control rod positions. Also the command and control perspective is often overlooked also. Many thanks

[@booognish]

Thanks, comrade 🤝

[@mysteryliner]

Yes, the plants had a lot of issues, but the ain reason Chernobyl happened was because of the communist system in place. The people who knew what could happen (running the reactor at higher power in the hours before, poisoning the reactor) were disregarded, treated like saboteurs who didn't want the test to succeed. Later those that knew what was about to happen were silenced / threatened by those who wanted & needed the test to proceed that night (because delays would make them/ their bosses look bad) ..... When it happened, the people who understood, were silenced / threatened because it was so absurd to say that a glorious NPP could go into meltdown. .... Those who went out with numerous Geiger counters (all measuring off the scale) were told to shut their fear mongering because the detectors were probably just malfunctioning, They even opened the amusement park to paint a picture that everything was okay and distract the people. All to climb in the party, get promotions

[@deanchur]

@@mysteryliner Similar situation is what caused the Great Famine in China (1958-1961). Party officials would overreport agricultural storage production to make themselves look better compared to other regions. Everyone thought that they had more food than they did and "overspent". That, and the monumentally stupid decision to kill off sparrows because they ate grain seed...which led to bug infestation that ate all the crops anyway.

[@mysteryliner]

@@deanchur probably so. Sadly with Chernobyl, it has had more than 30 years of hurtful repercussions. A reactor with many unique flaws (none that could have led to the accident) + communist tower climbing system that cause the accident. All that caused the negative feelings towards nuclear energy we still have today. 10million die each year from effects of air pollution, yet we are building gas furnaces so we can close nuclear plants.... Because "remember Chernobyl!! / nuclear is bad"

[@deanchur]

@@mysteryliner No idea how the EV revolution is supposed to happen without consistent energy to power millions of cars. Part of me that thinks that's by design in order to keep the majority people out of cars and thus restrict their mobility.

[@ashishkiift]

This is Gold. Thank You MIT Thank You KZbin. Another impetus for me to leave corporate and pursue sciences for my personal fulfilment and to correct my career journey that I mistakenly undertook in the wrong direction. Prof Short you are a gem !

[@arizonawut]

I'm so thankful to MIT and Dr. Short for sharing these amazing videos. I can see why he is such a well regarded professor. His passion for his craft shows through.

[@Chellz801]

These open courses being uploaded are amazing, thanks MIT for offering this as a resource to the public.

[@born2drum1]

47:30 is where this man earned my respect beyond his academic abilities. Big props to him for pointing this out !

[@miff227]

Fall of 2016, would be interesting to know if he believed the Russia-Trump hoax at the time, an example of the press flat-out lying by addition.

[@nathanwahl9224]

@@miff227 Exactly.

[@GamerplusMore]

Never trust the government when they tell you a certain amount of radiation is safe. He needs to go drink out of that water if hes so sure. You will find a looottt of nuclear engineers and physicists in that work that loove to downplay concerns too because they need more nuclear plants being built to get jobs

[@GamerplusMore]

Yep just as i suspected the last thing he says lol. "Hopefully that data will never be out"

[@tobiasloy8977]

As a layman, I love these type of lectures. I do struggle with the equations and that's allirght, but I do get a general understanding of the topic. Thank you for releasing it to the general public.

[@adamjetson5536]

As long as you are not collecting smoke detectors. (lol).

[@PrimalBlue-l6o]

As an Architect in Melbourne, I always wanted to study at MIT. I now see why it is so highly regarded around the world. This presenter is just AMAZING. Thank you!

[@nathanwahl9224]

Excellent presentation!!!!! I taught the event many times to newer operators at a nuclear power plant, they were preparing to take their reactor operator or senior reactor operator exam. Very well done, very well articulated. His comments about the media are spot-on. We could see it every single day as to how the industry was covered in the press. And the industry did nothing to counteract it, they're their own worst enemy. The one thing we had that added to the class for even more emphasis on operating safely was one of the engineers wives was a teen in Kiev at the time, and we had her on a video shown in the class describing what the effects were on the population in the area. It really brought home the importance.

[@petermullins2991]

I get a great deal of pleasure from listening to these types of people giving their knowledge to people such as myself, a 10 years of schooling plumber and gas fitter. My understanding is minuscule but my respect is huge. The students have my respect for being willing and able to study and understand these subjects. Stunningly fascinating.

[@johnnyreb280]

A CUNNING STUNT

[@MaxYoung-Maxinfet]

I love the tangents in this lesson and how passionate this teacher is about his subject

[@BachNBack]

I'd give this lecture a rating of 3.6 roentgen. Not great, not terrible..

[@r.b.ratieta6111]

"It's not 3.6. It's 15,000..."

[@BachNBack]

​@@rocketryanreed That joke went right over your head..

[@rocketryanreed]

@@BachNBack oh sorry my apologies I'm dyslexic I did not read the word correctly

[@BachNBack]

@@rocketryanreed It's a reference to Chernobyl, the TV series.

[@rocketryanreed]

@@BachNBack never seen it I'll have to watch it

[@carlgman273]

Been decades since I sat in a physics class. Now I remember why I liked it so much...it's because of awesome teachers like this guy.

[@faeries292]

I am not a physics person but this professor made me something so complicated so clear. I always loved those type off professors on college. They are knowlegde angels. Excellent lecture. Greetings and big respect from Croatia.

[@benmeister4]

I’m a history major and I couldn’t stop watching this. Amazing lecturing skill and such a fascinating topic

[@STOCKHOLM07]

As an English major, he spelled everything correctly and I understood some of it.

[@jeromebarry1741]

This is orders of magnitude better than anything published by mainstream media.

[@samlosco8441]

Same. My passion is in history and I aim to be a professor one day, but I also have a passive interest in the hard sciences and so lectures like this are perfect!

[@Tr1Hard777]

46:57 I know a guy that used to work at a nuclear plant, and he said the solution to pollution is dilution. Sometimes nuclear reactors release radioactive water in small quantities at a time into rivers as waste, but it is so dilute it can't cause damage.

[@winschmitt4919]

Trained as an ex-Navy Nuclear Submarine machinists mate / Engineering Lab Tech from pre-Chernobyl days, and after seeing the HBO series on Chernobyl- this was a fascinating look at some details I did not know, and very well taught. Much thanx to Prof Michael Short for this presentation. Great job!

[@sultanofsick]

Honestly Lagosov's (sp?) explanation in the trial in that series is one of the best laymen's explanations of the event I've ever seen. It's not perfect, but it gets the point across without making any REALLY offensively bad errors. The biggest one was throwing one temperature/heat balance item in what was otherwise a reactivity balance.

[@MCRoadk1ll]

This man explains something I've always had an interest in and still do, maybe even re-ignited it. Never had the luxury to study nuclear phisics. I wish I had teachers like this or there be more like him. Great stuff. Easy to follow, on point.

[@prgx52]

It is incredible how important good teachers are, this is also why investing in public education is so important, people like this guy get poached my industry so quickly when the wages are so disparate.

[@jimbrown609]

Students seem very respectful to

[@dale116dot7]

@Livin Vids Most reactors have a negative void coefficient which makes the reactor much closer to passive-safe, plus most reactors have a containment building ‘just in case’. That’s why TMI wasn’t that bad of an accident comparatively. The RBMK reactor looks close in design to Hanford B which was never designed to produce power but just make weapon fuel, the temperature was kept cold and that is one reason it was reasonably safe. Also, the reactor used natural uranium to produce Pu239, enriched fuel was used in RBMK. The RBMK required all of those safety systems just to be ‘close to safe’, but Chernobyl was not the first RBMK to have a catastrophic accident. Not a good reactor design, maybe not terrible.

[@JP-fn5xt]

Why not make the fuel rods round, and roll them out in accident ?

[@squamish4244]

@@dale116dot7 Hee hee "cold"...for a nuclear reactor. I know what you mean though.

[@Kayaya]

thank you so much for sharing this! i'm recently learning about what happened in chernobyl out of sheer curiousity, i've never been studying anything close to engeneering and a lot of the information i find online is confusing to me, but this i can understand up to a certain level. so thank you again for providing this gem of education. much appreciated!!!

[@chentiangemalc]

absolutely fantastic professor, great presentation. Thanks for making this available!

[@Abigail-hu5wf]

For those reading the captions: at 41:45, Michael says the words "thymine bridge", but the captions erroneously say "thiamine bridge". Thymine bridging is an alternate name for pyrimidine dimerisation, in which the pyrimidine-based nucleotides (thymine and cytosine) bind to each other vertically, rather than to the base horizontally opposite like they should. This can occur between two thymines (most common), two cytosines, or a cytosine and a thymine.

[@EnjoySackLunch]

Oh no killer mustard gas!

[@rampantpiper]

So, is this change in binding a cis- trans- thing like in organic chemistry? Same molecular formula, but different configuration ?

[@Abigail-hu5wf]

@@rampantpiper Not quite. What you're dealing with here is hydrogen bondings, not a change in isomers or enantiomers. So, first off we need to start with the structure of a DNA sequence, and how nucleotides (the letters that give DNA meaning, the A, T, C, and G molecules) arrange themselves. In all complex lifeforms (to my knowledge, in all non-viral genetic beings), DNA sequences are arranged in a *double helix* formation, a "spiral staircase" made of two twisted, spiralling backbones of deoxyribose sugar, connected together with "steps" made from nucleotides. These nucleotides are not randomly arranged: in fact, the order in which they occur is what gives DNA its ability to encode *genetic information,* the stuff that makes a carrot different to a parrot and makes hair different to a hare (sorry for all the English second language people... couldn't resist the puns). In _healthy_ DNA, the "steps" of that spiral staircase are always made of exactly two possible combinations of nucleotides: an adenosine (A) can bond to a thymine (T), or a cytosine (C) can bond to a guanine (G). Adenosine and guanine are both made of a compound called "purine", and thymine and cytosine are both made of a compound called "pyrimidine", so every single nucleotide pair should, in healthy DNA, be made of ONE purine and ONE pyrimidine, bonded together horizontally like so: |--A=T--| |--C=G--| Now, just because that's how DNA works, often two thymines will be directly "above" and "below" each other |--A=T--| |--A=T--| And that can also happen with cytosine. This would be absolutely fine, except that thymine and cytosine are verrryy slightly more unstable than guanine or adenosine are. Thymine "wants" to bond to adenosine... but if you give it a hard enough shove, it'll bond to another thymine (or a cytosine) instead. However, it's ALSO capable of making that bond *vertically,* not just horizontally. So you'd get |--A T--| | |--A T--| The thymines have joined together vertically AND they've broken their bonds to the adenosines they're meant to bond to. This pair-bonding of nucleotides is called *dimerisation,* because "di-" means "two" and "-mer-" means "join together". A dimer is two things joined together: for example, sucrose (table sugar) is a _dimer_ of a fructose and a glucose molecule. In this case, the thymines have dimerised together, and that is EXTREMELY not good. I won't explain why, but... in order to make proteins, your body needs to read the instructions (your DNA) in order to do so. It has no memory: it needs to read the instructions every time. This is a problem because dimerisation "breaks" that process, the machinery your cells need in order to read DNA just straight-up break when they hit a dimerised pyrimidine pair. The molecular biology is complicated, but it's very similar to shoving a piece of metal pipe into the spokes of a bicycle wheel: everything gets jammed up and breaks and that piece of DNA can't be read anymore. If that piece of DNA codes for a protein, then your cell is no longer able to make that protein. This is scientifically called *Very Extremely Bad* for cell health, and might kill it. Normally, that's OK though. The cell will be replaced by a new, healthy one and the diseased one will die. No harm done in the scheme of things. However... very concentrated radiation sources spit out a LOT of ionising photons (this kind of problem only happens when photons do the damage, it cannot result from alpha particles and for a beta particle to do it would be so unlikely as to be functionally impossible). That massive number of photons means that it can happen to _every single cell in your body,_ probably many many times across your entire genome. That means that, when a cell dies off... well, there's nothing to replace it, because the replacement died too. And so did THAT cell's replacement. All of your cells are dying because they can't be read. UV light causes extensive pyrimidine dimerisation, and this is actually the primary source of the damage caused by a sunburn. A sunburn is essentially an extremely mild radiation burn. Acute radiation poisoning is, then... basically getting a sunburn? On EVERY ORGAN IN YOUR BODY. Extremely Very Bad. So yeah, it's not a cis/trans isomerisation thing, it's a disruption in the ionisation of pyrimidine that leads to improper hydrogen bonding that disrupts the ability of RNA polymerase to transcribe mRNA which shuts down protein synthesis.

[@budfudlackerinc.1900]

Shut up. You don't know.

[@notsmoothie]

@@Abigail-hu5wf "scientifically called Very Extremely Bad" love this. I'm gonna use it lmao 😂🙏

[@malquid3811]

I am a layman and not experienced with high level physics but I could understand and follow this guys presentation barring the formulas of course. . Absolutely fascinating and eye popping. very well presented.

[@guciolini123]

42:05 I'm a MD. Definitely division nr 1. We use some method of finding cancer cells before they give any symptoms or even signs. What we find, we call cancer in situ or early stage cancer. If something is not a cancer, but can change in to cancer (f. e. leukoplakia of esophagus), we don't call it cancer, but this is the thing- It is not one mutation in a cell- it is a lot of them. Cells have many regulatory mechanism to not become cancer. They all have to be deactivated by mutations for the cell to start out of control divisions. Also 41:34- the more rapidly the cell is dividing, the more frequently it makes a copy of DNA and the less time there is for DNA repairing mechanism to do there job. If the DNA that is damaged gets copied the damage is permanent- it can't be repaired. Anthill this moment most damages to DNA (like tt-dimers he mentions) can be repaired by cells enzymes.

[@neruba2173]

Long story short: Its called cancer when it becomes a problem. Otherwise its just a temporary cell deviation.

[@BlueEyedFiend88]

Very clear, thank you for the info! I have a question if I may -what are your thoughts on the reported number of deaths caused by the radioactive fallout after the accident? The reason I am asking is because a relatively eminent local radiologist argues that the total number of deaths was around 40-50, and no more than that, compared to a number of around 4000 people that professor Short mentions in his video. I would love to hear your thoughts on the matter!

[@CharlieBourgeois_]

This mind blowing lecture is just a Tuesday for this guy. Amazing.

[@jonathanlee5314]

That's MIT for you! They truly do some of the most cutting-edge research and experiments on the planet.

[@Scallers813]

Dude your profile pic had me swiping at an eyelash on my screen for quite a while

[@FluxFreeman]

@@Scallers813 rekt

[@JohnnyVeritas]

This guy ROCKS!!! He has a perfect blend of audio and visual for all types of learners. He sets up his questions so well during his presentation, that you get to answer them correctly, and that keeps you engaged the entire time. I can't believe that was 54 minutes; it seemed more like 20 minutes. Great Teaching Doc!!!

[@JamOwnzU]

Quality. Teaching. Can't explain how precious people like this are for their skill and expertise enabling them to inspire the next generation and giving them confidence to ask questions and grasp the content. You just love to see it.

[@duncanferguson449]

00:53:57 “hopefully it never will be” really tied well into the whole “the error bars suck because thank goodness our sample size is small”

[@nathanwahl9224]

Exactly, but I'm afraid so many will misinterpret it's meaning. Most folks aren't that smart, in case you haven't figured that out yet.

[@badnewofficial]

I'm not a student, but I wanted a more technical look into the desaster and I got it. The professor truly explains it with clarity and at a level every could understand the fundamentals.

[@curtmcbee2238]

I get the feeling that none of his students ever skip class. In fact, they probably smuggle in their friends.

[@matsv201]

Well that is pretty typical of technical colage/unversity. When reading the core subject, nobody skips it, because that what people wanted to be there in the first place.

[@nightsage217]

Everyone tend to smuggle themselves into better lecturer's class. XD

[@NinjaofApathy]

I need a friend to smuggle me into a class like this...any takers?

[@SirMcAwesome]

@@NinjaofApathy I'll smuggle us in mate. But I'm not a student either, so we'll have to silently rope down from the ceiling during the lecture when the processor has his back turned, mission impossible style.

[@NinjaofApathy]

@@SirMcAwesome deal, you bring the rappelling gear, I'll bring the Mission Impossible theme music.

[@mikedrop4421]

I love how you can tell he is passionate about nuclear energy production and has real animosity towards the Chernobyl Management causing such a black eye on nuclear power.

[@satanofficial3902]

Whatever. You she entity lifeforces (including she entity lifeforces existing in XY DNA template bodies) don't process information sufficiently. You just go as far as whatever satisfies your Personal Opinions and gives you an endorphin/dopamine/whatever rush kickback. And there you stop because you're drug addicts for those rushes and nothing else matters to you except satisfying your drug addiction. A carrington event can happen at any, any, any time. ANY time. 100% inevitable. The planet will be radiation sterilized from all the meltdowns from pole to pole. Underground bunkers will be useless. No place to run, no place to hide. No one survives, everyone dies.

[@satanofficial3902]

You she entity lifeforces (including she entity lifeforces existing in XY DNA template bodies) smugly and willfully shoot yourselves in the foot and then act all shocked and surprised your foot hurts so badly.

[@satanofficial3902]

The totally inevitable next CME/carrington event ends everything right then and there when the cooling systems to the multi-hundreds of reactors and spent fuel pools fail.. As Porky Pig would say, "Th-th-that's all, folks!"

[@satanofficial3902]

This is the way the world ends. This is the way the world ends. This is the way the world ends. Not with a bang but with the whimper of uncontrollable diarrhea and vomiting caused by radiation sickness.

[@hoodyhoo1004]

@@satanofficial3902 bleak yet this is how I see it going down.

[@GiGaHarrySfotter]

Graphite tips is not entirely correct description. In RBMK reactor a control rod consisted of two connected parts - 7 meter absorber part at the top and 4.5 meters of graphite displacer part at the bottom. When a control rod is withdrawn to the top position and the top absorber part is completely outside of the core, the bottom graphite part remains in the core and displaces water to prevent this water from absorbing neutrons and slowing down the reaction. (note: to improve the yield of fissile material) But the bottom part of a control rod is only 4.5 meters long so at the bottom of the core there is still 1.25 meter of water which absorbs neutrons (the same at the top) and when a control rod goes down this water (absorber) is replaced by graphite (moderator) for 14 seconds until absorber part gets down. Why the bottom part is only 4.5 meters? There is only 5 meter space below the core for the bottom part when a control rod is fully inserted. Before AZ-5 was pressed there were about 60 control rods out of 211 still partially inserted for about 1 meter on average. The core was split into three parts - the bottom part with about 10 special control rods which were inserted from below and with about 1.25 meter of water (acting as absorber) present in about 140 channels, the middle part without absorber rods but poisoned by xenon and the most active top part which had dozens control rods. So when all control rods went down these rods pushed out 1.25 meter of water (absorber) from 140 channels in the bottom part and replaced it with graphite (moderator), increasing reactivity at the bottom significantly (about 3-4 times compared to the level before control rod insertion and about twice if compared to the most active top part). Such significant increase in the reactivity in the bottom part caused a runway there and explosion. ------------------------- Alex Demidov www.quora.com/Why-was-it-a-problem-to-have-graphite-tips-in-Chernobyl-reactor-control-rods-The-reactor-was-full-of-graphite-moderating-material

[@chamorvenigo]

IMHO, that's "the flaw" in the RBMK-type reactor. This video has animation on the power-spike produced from the AZ-5 shutdown procedure kzbin.info/www/bejne/p2THZKWwe7mlgsk . In layman term, there were 6 buttons for different types of emergency shutdown. During an unsuccessful electrical test, the reactor core was melting, so the AZ-5 shutdown button was pushed. This means all the control rods are to be inserted (lowered down from top to bottom) into the water channels of the reactor as fast as possible (there are other slower shutdown procedures). However, lowering down the control rods also mean lowering down the moderating rods which displaced water that was cooling the bottom part fuel rods (there should be equal amount of water replaced at the top part of the control rods. However, the water at the top is hotter than at the bottom). This cause a spike in nuclear reaction. So, instead of a typical nuclear meltdown, we get "very beautiful laser-like beam of blue light caused by the ionized-air glow that appeared to be flooding up into infinity".

[@aktchungrabanio6467]

I am in love with you

[@antonyhibberd8824]

Wow! This lecturer was awesome. Clear and concise. I actually understood the whole dang thing from start to finish.

[@larrysymms552]

his statement about the media at the end was spot on and I can't even imagine his thoughts now...

[@joshanonline]

It has been going on for years tho. But yeah, they got really bad with the elections. However, as they lied more and more, not just saying half truths or misframes, it helped me and many like me to break free of the brainwash. I am no longer a Democrat because of the media going insane with Hate and Fear mongering.

[@BakersTaste]

@@joshanonline lmao what? he's definitely talking about covid.

[@blackneos940]

@@BakersTaste Maybe. Or both. People have resigned from the FDA and CDC because of what's going on with the "booster" shot planning, even after people have taken the initial Vaccines.

[@oakson3045]

@@joshanonline Cheers bro.

[@nathanwahl9224]

@@joshanonline Nuclear power has been it's own worst enemy along those lines since it's inception. Kicked around by those very same scare tactics. 98% of what 99% of the public "knows" is wrong.

[@voice-of-wolf]

Wow, I heard a lot of times of this history from local scientist and researchers but never from MIT. That sound really interesting!) Thank you from Kyiv, Ukraine.

[@jaymanifold]

Michael Short possesses an all-too-unusual combination of academic/research ability and presentation ability. Bravo! (the anthropology of American vs Soviet risk-management cultures would be an entirely separate course … )

[@nerysghemor5781]

The book Midnight at Chernobyl goes into a lot more of those human and governmental factors...I highly recommend it.

[@Double_D_Creates_See]

wonderful job breaking this incident down, how it failed, and all the domino's that fell to create such a disaster. Even as an outsider and non-major in the intended fields of study, this professor did an amazing job at breaking everything down for understanding.

[@dons1932]

This hour flew by. Engaging lecturer! Unbelievable this is available for free. What a time to be alive.

[@benartee9493]

Thank you for this amazing lecture. Having grown up with this disaster as a kid it is helpful to understand better what led to this catastrophe.

[@rnelson1415]

I'm not highly educated, but this professor made this fascinating and easy to understand.

[@aethrya]

Dr. Michael Short is a physics gangsta. Been listening to his lectures for years and have learned _a lot_ about particle physics from them.

[@zacksteiber4569]

I'm 28..I never went to college. Been in construction my whole life. But I've always been so into the Chernobyl disaster, nuclear weapons ,power, and mainly just how it all works and the effects is has when it goes wrong. Everything about it interests me. Any suggestions on a good starting point to understand better? id love to learn all about it. I love how this professor really breaks it down. Great video !

[@mitocw]

You can view the full course at: ocw.mit.edu/22-01F16. Best wishes on your studies!

[@markspringfield6112]

Would recommend the HBO Chernobyl dramatic series. Tracks very closely to the description given here.

[@someoneelsethatisirrelevan1769]

@@markspringfield6112 HBO Chernobyl is not a good reference.

[@elric5371]

@@someoneelsethatisirrelevan1769 it is fairly accurate and a good starting point for those new to science, plus good entertainment.

[@someoneelsethatisirrelevan1769]

@@elric5371 yes, but if you're comparing it with real life documentation and witnesses' report, you'll realize something was off from the drama. You'll feel it as if it's another extension of the existing Nuclear Scare propaganda, so like I said earlier, HBO's Chernobyl is not a good reference, at least in the thorough perspective of the disaster. Or maybe I should put it "don't take HBO's Chernobyl as the only reference"

[@That_0ne_Dev]

Never did I think i'd find myself watching an introduction to nuclear engineering

[@Landlordbloke]

Though no where near the level of these students, I could be considered to be an enthusiastic absorber of scientific knowledge. I enjoyed and understood the concepts explored in this lecture. Michael Short is one very very good lecturer/ teacher - thanks.

[@genxjourney9705]

"Sit back, relax and enjoy a nuclear catastrophe" gave me a chuckle.

[@awkweird_panda]

If you listen closely, it was followed by the saddest ever "Yay!!" in the history of "Yays!!" at 0:39

[@stevemacbr]

Time-line 53:36 - Radiation dose,.... Prof. lets the (Schrodinger's) CAT* out of the bag. - He wisely states "I'm not going on record as saying - a little radiation - is not a problem,... we don't have good enough data" ( the error bars support either conclusion) - BOOM - followed by,... "The data is not out YET,... And hopefully* it never will be " !!! - IN OTHER WORDS,... WHILE WE CAN PLAY DOWN THE LONG-TERM EFFECTS (without this definitive data) WE CAN CONTINUE TO SELL NUCLEAR. !!! .

[@Bollibompa]

@@stevemacbr The design philosophy does not involve accidents like these and they have never happened again since. What is your point?

[@2hedz77]

Favorite quote for me was his story about his high school chem lab @ 28:50 "any of you played with iodine before?...i happen to have extensive experience with iodine in my home because I did all the stuff you're not supposed to do as a kid...kind of build your own chemistry set with things that somehow leak out of your high school...somehow..."

[@genxjourney9705]

@@денисбаженов-щ1б as if one would enjoy tragedy on such a large scale, his remark was so flippant you can only shake your head and sardonically laugh.

[@JumpUpNPullaco]

I appreciate you. I wish I had more Physics professors like you back in the day. You are right up there with Leonard Susskind when it comes to clarity and an obvious joy for your profession. Many thanks.

[@BlendworthPH]

This has been one of the best explanations of radiation and its affect / risks Ive ever seen. Especially the explanation of Sievert

[@marcodonati572]

Perfectly clear, Professor. I wish I had studied with you.

[@tobiaswilhelmi4819]

Unfortunately he is following entirely the lies within INSAG-1 told by V. Legasov during the Vienna investigation, so there are many faults regarding the regulations of operating. Those statements were made to blame the operators and deflect blame from the soviet science community, i.e. the Kurchatov Institute and others. For example there was no strict regulation regarding the number of control rods of 30. This was entirely made up and in fact was enacted as a regulation, but only after the 26th April 86. There was a passage within the operational manual that stated 15 rods to be present, but it occurred regularly that this margin was violated, and the consequences were that the shift supervisor had to comment why it occurred - that's it.

[@fightingforfaith3541]

This prof is most excellent in his ability to explain these high-level nuclear concepts so we lowly averages can understand.

[@NewWesternFront]

pshh speak 4 urself scrub n00b

[@nazryabchik2303]

My mom and sister were living 250km to the west from Chornobyl when it all happened. They were given 3rd category "Certificates of the Chornobyl victim", i got 4th category when i was born later and i didn't even glue a photo in:) However those who were fighting the catastrophe or lived in the area got 1st and 2nd categories, pension, privileges, free bus rides and huge respect while they were alive. I dont think there are many of them left today.

[@FireAngelOfLondon]

Some of the first men who went in to contain the disaster were signing up to die and they knew it. That is the highest form of bravery.

[@donaldmccallum8453]

When you think about it for awhile you might come to the conclusion that there aren't very many people from this era who are still alive, period (full stop)

[@fnhatic6694]

Nobody is going to want to listen to me because "he's an MIT professor", but there are two critical falsehoods in this presentation that clearly indicate this lecture was built more around 'popular misconceptions' about the Chernobyl accident then the actual reality. Misconception 1: 18:25 - there was not a 6" 'graphite tip'. This is for sure one of the biggest falsehoods about the reactor design and it drove me mad when I first learned of it, because I would keep asking "Why would they do that?" The graphite 'tip' is more accurately referred to as a graphite BALLAST. The professor is right that graphite certainly does its job moderating neutrons, but the problem is that water absorbs neutrons very handily. If you withdrew a boron control rod, you leave a void that would fill with water. The point with drawing a control rod is to increase reactivity, so why would you want it filled with neutron-absorbing water? So the control rods all had a large assembly on the ends of them that had a telescoping graphite ballast that would displace the water. These were not six inches, they were more like six *meters*. However, because of the size of the reactor chamber, the design required the ballast to be shorter than the total height of the entire reactor itself. It was a dimensions thing. When fully withdrawn, the ballast would float in the middle of the reactor, leaving a void at the top and bottom that would fill with water. When fully inserted, the rod would collapse slightly and those gaps would be closed. For whatever reason, a full-length ballast couldn't work, so this was the compromise. Which was fine, because it meant under normal operation, the center of the reactor would be where the highest reactivity was, while the top and bottom would be at lower reactivity. What actually caused the explosion was because of the gaps (ordinarily filled with water) had then filled with steam and created the positive void coefficient, upon lowering the control rod, the graphite ballast first displaced all the steam at the bottom of the reactor vessel. While nobody is certain what actually happened in the vessel as nothing could possibly accurately monitor it and survive, there were reports of two explosions. The leading theory is that upon displacing the steam and the instant spike in reactivity, the first explosion was actually contained inside the reactor vessel and shattered the fuel rods, which in turn damaged the rod channels, meaning the control rods were now hopelessly jammed and could not descend. With nothing but graphite now in the bottom of the reactor vessel, it was left with absolutely no brakes on and a few seconds later, the second explosion obliterated the reactor. Misconception 2: 27:25 - there was no graphite fire. High-purity graphite is incredibly hard to ignite, even under artificial conditions. gt-mhr.ga.com/graphites_all.html The red glow in the remains of the reactor chamber is blackbody radiation from graphite heated to 700C, but it is not the fuel for the fire. To whit - crucibles for smelting are sometimes made of graphite because they literally do not burn, and are used to melt metals that have melting points enormously higher than the stated autoignition point for graphite. While graphite may combust in thin sheets or powder or something, testing found solid blocks do not ignite.

[@michaellefevers4248]

I listened! Great info! Thanks for taking the time.

[@billigerfusel]

I like your words magic man

[@DaveyCrockett001]

Indeed, at least 2 critical falsehoods! Unfortunately, this "prof" is very likely highly representative of the extreme low quality of the post sec education system in the u.s.a.

[@FaradayBananacage]

I too can reject objective reality and substitute my own. In my imagination the Chernobyl incident created a massive cloud of cotton candy which we're still enjoying to this day.

[@Nostromo2144]

Just finally watch the 2019 Chernobyl series last week. This was a great and more in-depth overview to a lay-physicist of how radiation works, the sequence of events and contributing factors leading up to the disaster, and how radiation affects the human body and cells. Absolutely fantastic, thank you! The only thing that was skirted over, which the series went into a bit more detail about, was the 10 hour delay of the reactor running at 50% capacity (for economic reason & why the safety test was delayed to the night shift), which as a result created an unusually large build-up of Xenon, which then became a major preciptating factor during the ill-fated 'safety' shutdown. The mind boggles that anything like this could ever have happened - you couldn't have orchestrated the chain of events by sabotage if you tried most likely! But, leave it to Russian superiority, engineering and know-how to find a way...the most amazing political fallout was that Gorbachev said in 1991 that the dissolution of the USSR was in large part to the failures at Chernobyl and the total loss of confidence in the State by the people.

[@roberteltze4850]

I took an Intro to Nuclear Engineer class in the early 90s. One thing my professor emphasized about Chernobyl is that the reason temperature had a positive feedback was because it was designed both produce power and create weapons grade material. In the US (probably all non-soviet nations) reactors are built to do one or the other, never both. That lets us use designs that have a negative feedback so we don't get runaway reactions like Chernobyl. Yet I've never heard this detail mentioned in any other discussion about the Chernobyl accident. Can anyone confirm my professors claim? I have to believe my professor had good knowledge of the subject, he had considerable years of experience working for DoD and Los Alamos.

[@MrNickT]

RBMK reactors (like the ones at Chernobyl) were designed to produce power and plutonium. However, I don't think that has any bearing on the positive moderator void coefficient of reactivity. It still could have been designed with a negative moderator void coefficient of reactivity - after all, the other RBMK reactors were slightly redesigned and ~9 of them still operate today. One interesting/counter-intuitive note, to make the reactors safer, they needed to take some graphite moderator out (which would help to make the moderator void coefficient of reactivity less positive) and replace it with fuel. It may sound strange, but the solution to making the reactor safer was to add more fuel.

[@miff227]

are you saying the US reactors of the 50s/60s were not designed to make weapons-grade nuclear material? I thought this was the whole reason the MSRE got shut down, as it couldn't make that material

[@nathanwahl9224]

@@miff227 some were, but the commercial electrical production ones were not. You can't lump them all into one category.

[@peteparadis1619]

@@miff227 I was employed by the general contractor at Waterford 3 in Taft, LA, and it had NO ability to produce ANYTHING except electricity.. I had access to ALL the drawings and knew the plant inside and out..

[@truegret7778]

Excellent lecture. Thank you for sharing. I learned a lot from this one lecture about Chernobyl, and WWII weapons. I had the same question in the end as the student wrt Nagasaki and Hiroshima.

[@dba1222]

As a Brit, weird to hear a group of people not know of Litvenyenko. Still a huge incident in the UK to this day. Then they did it again in Salisbury. Crazy

[@MostlyPennyCat]

I've been learning everything I could about Reactor 4 my whole life, there details are fascinating. There's a few ever so slight simplifications here so I get to nerd tf out... 🤩 First, at the point of scram. When the control rods were out, rather than a column of water acting as an absorber, they were 'tipped' with a column of graphite for extra moderation. _But,_ and this is the big but, this big square reactor was design to react in the middle of the box, because the edges, where all the pipes and fittings interacted with the core, are not as strong as the middle (why is fascinating too but that's another story) So, in between three boron and graphite tips was a short column of water, absorbing neurons and _lowering_ the neutron flux density near the delicate edges of the reactor. Problem is, when you insert the rods, for a minute or two the short water column at the end is replaced by a long graphite moderator, right at the edge of the reactor... So, suddenly there is a large flux density jump at the party of the tractor designed to cope with low density. The water boiler. And it was trapped and compressed at the bottom. This is what cracked the rod channels, jammed all the rods and doomed the reactor. The positive coefficient did it's thing, threw the cap (1st explosion), the water flashed to steam, prompt neutron criticality, the Uranium got its running shoes on and did the ping pong mouse trap fandango and the resulting Rapid Unplanned Disassembly halted the fission process. Equivalent to a few tons of TNT, they found the telltale products somewhere in Norway I believe? I'll go dig up the sources later

[@Just.A.T-Rex]

Sources?

[@MostlyPennyCat]

@Comrade Vlad The best line in the mini series they did was about embarrassing a nation allergic to embarrassment. China are the same too, they will _never_ let anybody investigate the Wuhan coronaries lab. Regardless of if it were their fault or not.

[@GreatDogs]

Rapid Unplanned Disassembly --- Nice, have to remember that.. ;)

[@heikkiaho6605]

"the Uranium got its running shoes on and did the ping pong mouse trap fandango" :D great stuff

[@5bagsofpopcorn]

@@MostlyPennyCat it has little to do with nationality. Ask TEPCO today and they will still play down Fukushima. Remember how late they admitted that there actually was a meltdown in their cores. Its nature of men to deny the severity of a fucky-wucky of huge proportions when they are at fault for them.

[@Chakys92]

Even MIT getting control rod specifics wrong. Absorbing apart of the rod is not tipped with anything, there is about ~1.25m gap followed by ~4.5m graphite rod, which functions as reaction accelerator, an essential component to RBMK design not to leave channel filled only with water when rod is up (out), as that would be terrible for neutron economy. Think cheaper, as a soviet engineer to get it working with least possible fuel enrichment. It was a brilliant and cheap design, plagued by unrectified design flaws and terrible oversight in building phase.

[@hobbes0022]

I was looking for this comment, thanks

[@equim7363]

@@tommcdaniel9554 He is right, actually.

[@trixn4285]

That's correct. I don't know why so many sources say it's "tipped" with graphite. It's actually a pretty long graphite rod separated by a 1.25 m long telescope. When the control rod is fully retracted, the graphite displacer is located in the middle of the core height, with 1.25 m of water at each of its ends. The main flaw with that design is, that when inserting the control rod, the grahite part gets pushed out towards the lower end of the reactor displacing the 1.25m of water and increasing the reactivity in that part of the reactor. the most plausible scenario is that this led to a critical increase of reactivity on the lower end of the active core. What's shocking is the fact that they knew about this flaw as they had already observed it in another RBMK in Ignalina but they didn't provide any of the staff with that information.

[@equim7363]

@@trixn4285 Exactly!

[@niallmccaffrey791]

@@trixn4285 Nowhere do i see an explanation to the following... even as the reactivity is increased at the bottom of the core by the graphite rod moving down to displace the water, why is the reactivity at the center of the core not already much, much higher? There must be more steam voids near the center, and the xenon has been burning off more in the center. So yes, I understand how the reactivity at the bottom increases, but not why this is the tipping point.

[@KnitsFromTheVoid]

What a fantastic lecture, and what a skill to engage non-physicists and challenge actual physics students, all in one lecture. Wonderful. I would not have dropped out of Physics at my University if I had one or two Profs like this one. Actually this lecture has me considering to maybe continue my abandoned Physics degree on the side.

[@blewis1538]

Professor Short is very impressive. 35:12 interesting note, the Corium melted the floor and later it cooled into an elephant's foot-like column from the molten mixture of materials; ~20% of the core original fuel, the biological shield, concrete, sand, iboron, lead and graphite. Also, the recent attempt to contain the site with a steel and concrete outer sarcophagus. Time will tell if it will help control the fallout.

[@MrBritishNinja]

I think it's so interesting that Buster went from being a mama's boy, to getting awards from Army, to being a professor of Nuclear Disasters

[@russ18uk]

The first moment I saw him I saw Buster. Glad he got his hand back!

[@gabrielfallon8629]

@@russ18uk He's going to be all right

[@sethtrowbridge9122]

the reactor failed because of a loose seal

[@pattybaselines]

You didn't have to do him like that

[@twelvecatsinatrenchcoat]

Honestly I kind of love this idea. Buster finally breaks free of the toxic codependent relationship with his mother and it turns out he's actually a genius. Finds his confidence, grows up fast, becomes an MIT lecturer who desperately avoids his family's calls, none of them have heard from him in years, has a supportive cute girlfriend in the chemistry department. He even sees Michael as a toxic screwup.

[@Ullish1989]

Omg finally someone talking about the Xenon gas rather than just saying "they threw caution to the wind"

[@57oldsmobile]

What a great professor, the best lecture I have ever seen. Thank you for your efforts!

[@TransSappho]

As someone studying geology and paleontology, seeing Gy was a bit confusing at first, since I’m used to it standing for Gigayear(also sometimes written as Ga for Giga-annum)

[@billyworkman4204]

Having the opportunity to try to obtain some amount of understanding of the nuclear fusion process, and what happened at Chernobyl's meltdown is nothing more then my pleasure.

[@jask320]

It is amazing, how Michael can use simple language for complex things. One of the best explanations I ever heard on this topic. It is too much lie in the official soviet documentary, however lots of truth as well, when you watch it just use the common sense rule. I am Ukrainian and I was born in 1987, a year after this tragedy, and I am pretty sure that Chernobyl was the last nail into USSR`s coffin. The only good thing, now, the vast majority of decays on its own schedule called a “half life" already happened, and 30-km zone comes back to life, there is a lot of wildlife there and it is safe to travel if you know where contaminated spots are and you have a dosimeter-radiometer in your pocket and eating local mushrooms is not a part of your plan =)

[@EduardO-gm7hx]

Gorbachev was the last nail in USSRs coffin

[@RockyRacoon66]

An amazing masterclass! Very very impressive delivery.

[@amirrezaghayori]

this teacher is just amazing! the interactions, involving students in the topic so its not just a lecture. its fantastic I wish I had a teacher like this when I got my lisence

[@ChefNongak]

46:42 The teacher blows my mind for the entire video and ends up with a statement on a social problem with astonishing charisma. Be sure I'm going to reference this guy in the future.

[@coryanderson7911]

Such a clear and concise lecture, this professor is fantastic! Thank you for providing this lecture, it was very captivating and informative. How I wish I could afford such quality education as this regularly. I would have to be a permanent resident, as I would not be able to pull myself away from the insatiable hunger to learn more than just a single class, let alone a subject, can provide about the world around us... Finding this video, and your channel with material like this will be the next best thing! Thank you, kindly!

[@emreyldz4324]

Hi, i am a doctor from Turkey and i absolutely love this course, i only had lessons in physics in high school and biophysics in university but you made it so easy that i could understand this course even when i was 14 years old. It's my second time watching it, and i loved the parts where you physicists talked about the biological effects of the radiation, difference between gamma and beta rays, Iyodine tablets and which parts of the human tissue does radiation effect most. I also liked the comment section, where scientist all around the world praised your lecture. Wish we could accesses all this lectures from other universities also so that genius and curious people all around the world would be able to reach it. Wish you a succesful career in the field of nuclear physics.

[@ianzapcic1102]

I'm glad Buster Bluth's studies finally paid off and now he's teaching college courses. (In all seriousness this was a great lecture!)

[@emanuelmota7217]

Ya gotta hand it to him. Especially as that reactor may have had a loose seal.

[@demensdeum_live]

Hi from Russia, wanted to put my 2 pennies. Soviet physics couldn't calculate right - consequences of making reactor to work in those turbine experiment conditions, that's why there was instructions to not do what they did. Some government guy who came up with idea about turbine testing on Chernobyl wanted to get a promotion, and they started to make this "experiment" against all safety instructions provided for RBMK-1000. Great lecture.

[@kevino.7348]

Hello from USA.

[@ms-jl6dl]

That's what we in then Yugoslavia were told. Human failure. And that the new manager that allowed all this to happen was a former high-school teacher who was trying to impress his party colleagues.

[@danielpittman889]

Hi from Colorado! The English phrase is "to put your two cents in" and not "two pennies". I know cents and pennies are the same thing, but we use cents in that phrase. But I knew what you meant!

[@cuqrious]

My reaction is really quite emotional. To have access to these lectures is both amazing and humbling. About the clearest of all my memories is the 26th April 1986. I actually turned and snorted in anger at the radio announcement that 4 people had been killed. I was insulted that the Russians thought us so stupid that they could make such a broadcast. I completed a science degree in 1965 and spent a lifetime in biological research and these programmes are wonderful to enjoy in my '80's. Very sincere thanks from New Zealand.

[@codaalive5076]

This is very good course and good explanation of what happened in Chernobyl. Guy in helicopter filming burning graphite was Russian journalist. Iirc one of crew members died, he survived with minor problems. Regarding US nuclear accidents; TMI was minor one but many tests irradiated soldiers, civilians, huge areas of nature reserves, several accidents happened in labs where people died, other meltdowns, etc. If you got to do it, do it well says a song.

[@dangallagher8034]

I'm returning to my studies in math because of the inspiration this course (and professor) resurrected. Thank you sincerely.

[@OmegaRedFan]

Don't get all mathed up

[@peachfreude]

I didnt realise I watched the whole video. Props to this guy for making his lecture interesting. Such a well articulated lecturer.

[@brianjames2549]

Good "fun" lecture. I used to do the same with my A -level Physics classes and then ask them their opinions on nuclear power. Good stuff to get them thinking, especially when you add in climate change and power production. Life is never simple!

[@satanofficial3902]

Having a radiation fetish is like having a fetish for aiming a gun at your foot and then pulling the trigger. A very, very strange way to get your endorphin/dopamine/whatever kicks. You she entity lifeforces (including she entity lifeforces existing in XY DNA template bodies) do the strangest things.

[@Datan0de]

"Life is never simple!" is something I wish more people would take to heart. It's definitely true in science, but extends to other areas like politics and history. I'm fond of saying "the universe doesn't owe anyone a simple explanation." Too many people hear a sound bite or read a summary article and assume they have enough information to form an opinion that carries the same weight as an expert in the field.

[@denysvlasenko1865]

Length of graphite tips of control rods is incorrect. It's not 6 inches. It's way longer: 4.5 meters. Wikipedia has a much better description: """... the control rods have a 4.5 m (14 ft 9 in) long graphite section at the end, separated by a 1.25 m (4 ft 1 in) long telescope (which creates a water-filled space between the graphite and the absorber), and a boron carbide neutron absorber section [7 meters long]. The role of the graphite section, known as "displacer", is to enhance the difference between the neutron flux attenuation levels of inserted and retracted rods, as the graphite displaces water that would otherwise act as a neutron absorber, although much weaker than boron carbide; a control rod channel filled with graphite absorbs fewer neutrons than when filled with water, so the difference between inserted and retracted control rod is increased. When the control rod is fully retracted, the graphite displacer is located in the middle of the core height, with 1.25 m of water at each of its ends. The displacement of water in the lower 1.25 m of the core as the rod moves down causes a local increase of reactivity in the bottom of the core as the graphite part of the control rod passes that section. This "positive scram" effect was discovered in 1983 at the Ignalina Nuclear Power Plant. The control rod channels are cooled by an independent water circuit and kept at 40-70 °C (104-158 °F). The narrow space between the rod and its channel hinders water flow around the rods during their movement and acts as a fluid damper, which is the primary cause of their slow insertion time (nominally 18-21 seconds for the reactor control and protection system rods, or about 0.4 m/s).""" Not well explained what exactly caused the explosion. Not explained why specifically "almost all rods were removed from the core" was a bad thing. The correct sequence is as follows: * Steam valves closed to start turbine run-out experiment. * Pump power starts going down since turbine runs out (slows down) and amount of power from it goes down too. * Recirculation slows, water gets hotter, boils more. * Reactor power (which was around 200MWt thermal) starts slowly rising due to increased boiling + slightly positive void coefficient. (This also starts to burn off Xenon). * Operators are confused why power rises, panic a bit. * After some tens of seconds, Akimov decides to press the scram button - the AZ-5. * All control rods simultaneously start lowering into the core. Control rods are in vertical water tubes, not in gas space, for cooling purposes. Graphite tips go down as well, displacing 1.25 m of water in the lowest part of the reactor with graphite. This is where "almost all rods were removed" plays its bad role - almost all rods were removed means almost all rods go down at once. Graphite tips moving down replace water, an absorber, with graphite, a moderator! * Now power spikes VERY fast, primarily in the lower third of the reactor, burning off all Xenon (absorber gone -> positive feedback), flash-evaporating all water and rupturing water piping (absorber gone -> positive feedback). * Fuel melts, evaporates in many places, some isotope analysis suggests even prompt criticality was reached in some small volumes of fuel. Reactor pressure vessel ruptures. It looks like control rods lowered only ~2.5 meters before they ... stopped existing along with everything else. IOW: the absorber sections of the rods could affect only upper ~2.5 meters of the 7-meter high reactor core.

[@klujics123]

Thank you for your explanation. So if you would have been on site and walked into the control room the moment they detected and started to panic… what would your instructions have been knowing what you know now? (This would have been my question to the Prof). Any suggestions?

[@quantumleap359]

Amazing lecture. Even when the subject caused a tangent, the tangent was documented to some extent! I was very impressed with Mr. Short's teaching ability plus his superb control and display of his teaching graphics and information.