Chernobyl: Open Wide, O Earth

May 20, 2019 8:39 PM - Season 1, Episode 3

The Chernobyl Commission begins the investigation into the causes of the disaster.

(I'd like to propose moving to per-episode posts. There has been plenty of discussion and it's all off the main page.)

posted by sylvanshine (42 comments total)

I think the miners were exaggerated.

The wife is an idiot.

I'm still not loving this show.
posted by k8t at 11:11 PM on May 20, 2019 [1 favorite]

Did they turn the firefighter's wife into an idiot just to set-up an arrest by the KGB, which in turn set-up a conversation with the KGB that had no apparent pay-off? There must be a more sensical way to tell us that KGB = baghouls.
posted by Brocktoon at 11:56 PM on May 20, 2019 [1 favorite]

Some (graphic) details of what Lyudmila Ignatenko experienced are described here.

She didn’t know exactly what had gone wrong at the reactor. She just knew that her husband was dying.

(The article explains why she was holding shoes at the funeral, as well.)
posted by FallibleHuman at 12:36 AM on May 21, 2019 [16 favorites]

She's an idiot because she went to be with her suffering husband despite personal risks that she couldn't possibly have understood? I'm an idiot, too, I guess, as I would have done the same thing.

I still feel a bit like my lack of understanding of nuclear reactor operating procedure is adversely affecting my appreciation of the drama. Am I supposed to know what button AZ-5 is supposed to do? I'm trying to treat it like a sci-fi premise, where of course I wouldn't expect to understand how the Holodeck has malfunctioned, but the historical nature of the event makes me want to understand more. I just picked up Midnight in Chernobyl to read after the series, so hopefully that will help.
posted by Rock Steady at 5:50 AM on May 21, 2019 [15 favorites]

How were the miners exaggerated do you think?

There are many first-person accounts of them doing their work in the nude.

what button AZ-5 is supposed to do

My impression just from context was that it's supposed to be some kind of emergency stop button, but it didn't work.
posted by soren_lorensen at 5:59 AM on May 21, 2019 [5 favorites]

Lyudmilla is not an idiot. She is very young, she doesn't know much about radiation, she's trusting the officials who are LETTING HER IN THE ROOM. They are newlyweds and Vasily is the love of her life. She is a real person and has suffered a great deal and it's shitty to call her an idiot. This stuff actually happened.

I didn't like this episode as much as the first two but I still liked it. The coal miners were awesome.

The music continues to be eerie and haunting and I love it.
posted by Aquifer at 6:21 AM on May 21, 2019 [30 favorites]

My opinion is colored by the social media comments of friends who are historians of this period (most focusing on Ukraine but some Russia) who feel that this show is dramatizing events far beyond reality.
posted by k8t at 7:21 AM on May 21, 2019

Nurse: DON'T GO BEHIND THE CURTAIN OR YOU WILL BE FORCIBLY REMOVED

5 seconds later behind curtain.
posted by Brocktoon at 7:40 AM on May 21, 2019 [1 favorite]

Lyudmila's actions made sense to me in the context of a world where information was routinely withheld or misrepresented in the service of the state and you had to bribe professionals in order to get anything done. Knowing what any citizen knew at that time, why should she have automatically believed them about how dangerous his condition is?
posted by Countess Elena at 8:14 AM on May 21, 2019 [22 favorites]

And given that they were basically leaving him to die in agony alone, I can see how she'd think that it was just neglect, rather than danger, that was the problem. I mean, she gets yelled at by a nurse but there's nobody around to actually enforce whether you go behind the plastic or not.
posted by TwoStride at 8:32 AM on May 21, 2019 [5 favorites]

Am I supposed to know what button AZ-5 is supposed to do?

In the context of the show, you shouldn't know more than what they mentioned, which is that it is a shutdown button. It has been established that this kind of reactor “can’t” explode in this way, but it clearly did and the scientists are trying to figure out why. From the interviews, it seems they pressed the AZ-5 shutdown button right before the explosion. Right now you are supposed to think “although it is counterintuitive, could the shutdown button be the key to why the reactor blew?” Of course, since it is based on a real disaster, you can read about what people believe happened if you want to.
posted by snofoam at 10:56 AM on May 21, 2019 [5 favorites]

Lyudmila Ignatenko's story in the show is, so far, a pretty faithful adaptation (there may be some minor changes I'm missing) from her testimony in Svetlana Alexievich's oral history Voices from Chernobyl, which is an absolutely harrowing read but very much worth your time. Her account and several others are excerpted in this NPR piece (text, not audio).
posted by karayel at 1:15 PM on May 21, 2019 [13 favorites]

I also can't recommend enough the companion podcast for this show. It's really interesting and they are very explicit about "this was different than real life for X reasons" (e.g. the divers did actually have to work in the dark, but they were familiar enough with the layout of the plant that they could kind of feel their way along, but for a TV show you can't have it be pitch black, so the dynamo flashlights were an addition) and "as crazy as this may seem, this really did happen pretty much just like we're portraying."
posted by soren_lorensen at 1:35 PM on May 21, 2019 [8 favorites]

The men weren't isolated just because they might be radioactive. Many died from infection.
posted by Brocktoon at 4:39 PM on May 21, 2019 [1 favorite]

Really liked the characterization of the miners. Nice colour telling 'In Soviet Russia' jokes, patting coal dust onto the party man, and being skeptical of the breathers and compensation.

I get that they understood that they were getting into bad juju, but did they understand exactly what they were signing up for (radiation exposure leading to early painful death)?

It's HBO, but the full frontal was something that was significant to the plot. Kudos.

I totally get Luydmila's characterization and it drives the "radiation - the invisible killer" and how little lay persons understand it.

Legasov (Jarred Harris) casually letting Shcherbina (Stellan Skarsgård) know they they've both already taken enough exposure for painful early graves was shiver inducing.
posted by porpoise at 6:15 PM on May 21, 2019 [5 favorites]

Also incredibly effective in that same conversation: Legasov describes the stages of radiation poisoning and we realize that (a) we've just seen the first stage -- the burned men jovially playing cards in their hospital room -- and (b) the show is almost certainly going to show us the remaining stages.

The makeup/effects on the victims were astonishingly gruesome.

I'm still bothered by the show's decision to composite all the scientists down into just two characters; it feels really lacking when it's contrasted against the many layers and characters in the Party apparatus.
posted by We had a deal, Kyle at 11:29 PM on May 21, 2019 [3 favorites]

I think combining the scientists is necessary for narrative purposes in this format. Too many characters gets hard to follow, and if new ones are popping up all the time with new information, the viewer is distracted by "who is that and why do I care what they're saying?"

The makeup was indeed horrific - and even more so when they left the last one not shown. (per podcast, apparently filmed and then changed their minds.) It's like - we've shown you this much, how bad must it be when we don't show you the last guy.

Also in the podcast - the prison scene was shot in an actual former KGB prison in Vilnius, Lithuania.
posted by dnash at 8:59 AM on May 22, 2019 [6 favorites]

I think combining the scientists is necessary for narrative purposes in this format.

I agree. In fact, I don’t disagree with any of the production decisions so far. I think the story is remarkably well told.

Also, there were other scientists, like the guy who was also working on a Saturday in Minsk and the woman on the phone who gave info in code and a bunch of people at the plant itself.
posted by snofoam at 9:25 AM on May 22, 2019 [4 favorites]

A little subtlety I loved: Scherbina and Legasov transitioning to first names as they find themselves facing the reality of the situation together. Boris and Valery - and then Valera, the diminutive, as Scherbina tries to rally him - and then back to Comrades Legasov and Scherbina during times when they butt heads, and find the gulf of party strictures and hierarchy yawning between them.

GoT Watch: Jeor Mormont in amongst the miners!
posted by jurymast at 10:25 AM on May 22, 2019 [10 favorites]

I like the evolution of Scherbina and Legasov's relationship too. One thing I like about Legasov is that he can't seem to stop himself from piping up about safety hazards and giving harsh truths to people who don't want to hear them. (My understand is that part of the reason he was chosen for this committee was because he was such a Party loyalist and was expected to toe the line.) I liked Scherbina's reaction to Legasov confronting the KGB guy. "He just thought you were a naive idiot. Naive idiots aren't dangerous." Or something.

I like how they're handling the "mystery" of the reactor exploding. I've rewatched the first episode and admire how they handled it even more. We (maybe) know more or less why it exploded, but at this point, no one else really does.

I really love this series.
posted by Aquifer at 10:53 AM on May 22, 2019 [9 favorites]

but at this point, no one else really does

Well...we'll see how it plays out in the show, but there is stark difference between the show and history when it comes to all the "RBMK problems?? Impossible!" statements on the show, including who is portrayed as saying them.
posted by sideshow at 11:23 AM on May 22, 2019 [2 favorites]

It's probably mostly my shoddy understanding of nuclear physics but I'm pretty puzzled at the confident assertions that RBMK reactors can't explode. It's....full of nuclear fuel? How could it NOT explode? It's really, really hot? Hot things...explode?
posted by Aquifer at 12:01 PM on May 22, 2019

It's probablconfident assertions that RBMK reactors can't explodey mostly my shoddy understanding of nuclear physics but I'm pretty puzzled at the confident assertions that RBMK reactors can't explode

I think it was more of a "we build fabulous things that never fail, it's unpossible that we've made a mistake in the design of this facility."
posted by Gyre,Gimble,Wabe, Esq. at 12:50 PM on May 22, 2019 [3 favorites]

I really like this show and I really liked this episode.

The miner saying "if these worked you'd be wearing them" about the masks and just slapping it down on the desk and walking out. I loved everything with the miners. Especially their DGAF about being starkers because it was hot and exhausting work.

The makeup was horrifying. And Lyudmila getting constantly irradiated while comforting her dying husband made my skin crawl. Her telling him about the sights of Moscow was such a lovely little insight into how much they loved each other.
posted by biscotti at 2:31 PM on May 22, 2019 [8 favorites]

I think it was more of a "we build fabulous things that never fail, it's unpossible that we've made a mistake in the design of this facility."

I think so too, and I think it's a choice to make the viewer wonder where the pure obfuscation ends and the mystery begins. We can go to the internet and find out how this was supposed to work, but how would a Soviet citizen know -- even a scientist, who has to resort to coded conversations using the periodic table just to find out what kind of remedial efforts are being made?

If you look this show up on Twitter, you find two extremely American takes on it --

Team Red: Chernobyl shows what happens under the tyranny of leftism.
Team Blue: Chernobyl shows what happens if scientific crises are handled by party loyalists instead of actual fucking scientists.

And never the twain shall meet. But I found this cartoon anyway, which I liked.
posted by Countess Elena at 3:47 PM on May 22, 2019 [8 favorites]

I think it was more of a "we build fabulous things that never fail, it's unpossible that we've made a mistake in the design of this facility."

To add to my earlier comment: Lots of people, including people portrayed in this very show, knew all about how much the opposite of "unpossible" it was that the design of the RBMK reactors was flawed. They knew their approach was inferior to the Western designs when it came to safety, but they planned on making up for that by training their people to a much higher standard than lets say the Americans.

It's possible who knew what, and when, will be revealed in future episodes. In fact, there is probably going to be whole bunch of history of the Soviet nuclear program.
posted by sideshow at 8:23 PM on May 22, 2019

The Inside The Episode short and the podcast both note that the miners' work ended up being unnecessary. I don't think the episode itself sold that very well; I hadn't really connected Legasov and Khomyuk comparing notes on their 40-50% estimates with what the miners were being asked to do.

Fundamentally it feels like Legasov is being faced with a series of escalating trolley problems: to protect the safety of the many he is being forced to personally send increasing numbers of the few to their deaths.
posted by We had a deal, Kyle at 11:30 PM on May 22, 2019 [7 favorites]

The Inside The Episode short and the podcast both note that the miners' work ended up being unnecessary

The show also left out how the "helicopters dropping shit into the reactor" was not only not that effective, it actually made a lot of the future remediation efforts much harder to pull off. Also, Legasov and company knew at the time it wasn't the best thing to do, but they did it because "doing something, anything" immediately was much more important than doing the correctly thing slightly later.
posted by sideshow at 9:07 AM on May 23, 2019 [1 favorite]

It's probably mostly my shoddy understanding of nuclear physics but I'm pretty puzzled at the confident assertions that RBMK reactors can't explode. It's....full of nuclear fuel? How could it NOT explode? It's really, really hot? Hot things...explode?

It's a bit more complicated than that, and also depends on what you mean by 'explode'.

A nuclear reactor cannot explode like a nuclear weapon. Runaway nuclear fission chain reactions release so much energy that they tend to blow apart the critical mass of uranium or plutonium long before most of it has taken part in the reaction. This is why nuclear bombs are - fortunately - very hard to build; much of the effort of the Manhattan Project was expended in building a bomb that would burn even a moderate amount of its fissile material before vaporising itself.

What could happen to a nuclear reactor is that the reaction runs away to the point that it immediately boils the coolant water thus causing a steam explosion. That's what the scientists seen in Chernobyl are talking about when they refer to the reactor exploding. The reason for their confusion is that a properly designed and operated reactor should not be able to get close to having that happen.

Firstly, a reactor ought to be designed so that its own natural physical processes do not encourage a runaway reaction. However, the RMBK-1000 reactor had an inherent problem called a 'positive void coefficient' which means that as the core gets hotter its 'reactivity' - the ease with which the fission reaction increases - gets higher. That means the reactor gets even hotter, the reactivity gets even higher, and a runaway positive feedback happens.

Now, the Chernobyl operators were well aware of this, so the second safety element should have applied. A nuclear reactor is controlled by inserting or withdrawing rods of neutron-absorbing material that damp the chain reaction. Any reactor will have a 'scram' system that quickly inserts all the control rods so as to bring the nuclear reaction to a halt as rapidly as possible. (Yes, I am oversimplifying a bit here, but this is the essence of what happens.)

What was really confusing Khomyuk and Legasov at the end of the episode was the apparently credible evidence from the reactor operators that at the end of the experiment they had been running they had initiated a reactor scram to shut the reactor down, at which point Reactor 4 had exploded. That simply should not make sense - whatever else might have been going on, inserting all the control rods should have killed the reaction, not made it run away catastrophically.

I won't spoil the explanation, as I imagine the series will set it out, but in brief it turns out that the RMBK-1000 had a really subtle and nasty design flaw (beyond just having a positive void coefficient) that meant that a scram could cause surprising behaviour. Combine that with the way that just before the explosion the reactor had been being operated far outside its normal, stable operating regime, and there was a recipe for a disaster that, unless you understood those issues, would have seemed impossible.
posted by Major Clanger at 3:11 PM on May 23, 2019 [32 favorites]

Does anyone know of material that would explain how realistic last episode's "steam explosion would spread huge radiation across Europe etc" stuff was? I understood this to be the biggest danger presented so far (as of ep 3) and am curious to read more about it; it sounded akin to a nuclear weapon going off in terms of effects. (Maybe they even said that in the episode, I don't remember.) (Yes I see the irony of my proposing episodic posts and then asking an ep 2 question!)
posted by sylvanshine at 6:20 PM on May 23, 2019

Can't speak to the realism of it, either in what would have happened or what Legasov said, but what they were describing was hugely, vastly, incomprehensibly worse than just setting off a big-but-not-unusual nuke.
posted by GCU Sweet and Full of Grace at 9:03 PM on May 23, 2019

I've been reading Midnight in Chernobyl (which didn't come out until after the series had been written/filmed) and recommend it for those who want to fill in some of these gaps--it does a great job of explaining the RBMK reactor design flaws Major Clanger is talking about, and setting them in the context of the development and governance of nuclear technology in the USSR.

The book doesn't spend as much time on the steam explosion threat as it does on the potential consequences of a "china syndrome" outcome where the melted core burns through the concrete and down into the ground(water), but it does suggest it was a real concern for those managing the response--I'm not sure about the calculations given onscreen, but I gather that what made the explosion scenario so potentially catastrophic is that it would have blown up the other three Chernobyl reactors too, quadrupling the amount of nuclear material involved and creating a "gargantuan dirty bomb" (Higginbotham's words).
posted by karayel at 10:54 AM on May 24, 2019 [3 favorites]

I think the size of explosion stated (megatons?) is wildly unrealistic, but yes, there could have been a much larger explosion that would have certainly dispersed all the contents of Reactor 4 and might well have destroyed the other 3 reactors. That would have been much more than four times as bad; horrifying although the Chernobyl disaster was, only a portion of the radioactive fission products within the core were released (and only a small percentage of the core itself.) The decades of subsequent work on the Sarcophagus and the New Safe Confinement are intended to keep the rest of what remains of Reactor 4 in place.
posted by Major Clanger at 12:33 PM on May 24, 2019 [2 favorites]

What always floors me about Chernobyl when I remember it was that it continued to be used to produce power for more than another decade. People worked right next to the sarcophagus! They walked through the main corridor that ended in the blocked off entry to the No 4 plant!
posted by tavella at 1:07 PM on May 24, 2019 [4 favorites]

Really? Ugh. I was already going to have nightmares just from binging the first three episodes. What an awful dread-laden situation to go to work in.
posted by janell at 9:57 PM on May 26, 2019 [1 favorite]

The actor playing Glukhov, the head miner, is Alex Ferns, who played the sexy but evil Trevor Morgan in the early 00's on EastEnders.
posted by DirtyOldTown at 8:49 AM on May 27, 2019 [3 favorites]

"Does anyone know of material that would explain how realistic last episode's 'steam explosion would spread huge radiation across Europe etc' stuff was?"

I'm only now getting around to watching the remaining episodes, and I just finished this one. But that line was from the previous episode and it was complete nonsense. I can't really emphasize that enough.

When I heard that line -- and her estimate was "two to four megatons" -- I was nonplussed and for days I ruminated on it trying to think of some way to make any sense of it. From a basic physics standpoint, there's not enough energy in an "instant" vaporization of that large-ish amount of water to produce even a kiloton TNT equivalent explosion, much less a megaton.

For reference, the Trinity test, Hiroshima, and Nagasaki explosions were all in the twenty kiloton range. So what she described would be like 1,000 to 2,000 times those, not even (directly) from a nuclear reaction (fission or fusion), but merely from the heat of the "corium".

That would imply that you don't need a supercritical reaction to produce a world-changing bomb -- you'd just need a critical mass contained long enough that has enough heat to "instantly" vaporize a big tank of water.

That would have greatly simplified the task of producing the first atomic bomb!

It would also mean that a bomb in the fusion range -- megatons -- would be achievable with just a small fission bomb and a bunch of water. (Note that if that quantity of water could be "instantly" vaporized by some corium, that's enough heat that it wouldn't make much of a difference if the water were fully enclosed or if it were just exposed on the surface, like a lake or the ocean.)

(The only thing I thought might somehow make sense was the possibility of dissolved radioisotopes in the volume of water repeatedly going prompt critical. That would be bad. Still not kilo/megaton-bad, but a much worse situation. I certainly don't know how to begin to calculate the possibilities of that and I suspect no one does -- several of the worst criticality accidents involved radioisotopes in solution just happening to flow into a criticality configuration that no one anticipated was possible.)

So, in summary, her statement of "two to four megatons" implies not only that no one ever needed to solve all the very hard problems involved with achieving supercriticality (so fast that a prompt critical reaction occurs through all the nuclear fuel -- that is to say, before it is blown too far apart from itself to fizzle out) and some quantity of meltdown slag (dropped in water or whatever) would manage an explosion equivalent to twenty-thousand tons of TNT, but that somehow it would manage to produce an explosion about 150 times that, which would be about one-fifth the size of the biggest bomb the US ever tested...without, you know, what we mean when we talk about a nuclear bomb.

A kiloton doesn't even make sense. It can't make sense.

Alternatively, what might make sense is that the estimate she gave wasn't explosive yield per se, but rather an informal estimate of an equivalent amount and distribution of radioactive fallout. That is, maybe she meant "a conventional four megatons bomb's worth of fallout". (This is because unless a nuclear bomb is designed to produce a lot of fallout, in these relative terms it doesn't.)

As to the actual facts of the matter, I did some research and found that the screenwriter had only one source for that estimate, it was actually somewhat higher so he was slightly doubtful, and thus he reduced it to the 4-6Mt estimate. There's a lesson in that, somehow. Anyway, I couldn't find that source myself, but I can guess. You won't find anyone, anywhere, saying anything else like it unless it's also derived from that source.

That's not to say that it wasn't a very serious concern. At the least, it would have greatly magnified the area of the distribution of radioactive isotopes, involving spent fuel and waste stored at the plant as well as some of the fuel from the other reactors. There's no reason, though, that the other reactors would have been in danger of meltdowns as a result because if they expected this to happen, they could have shut them all down with the control rods in place.
posted by Ivan Fyodorovich at 7:15 AM on June 6, 2019 [2 favorites]

"And Lyudmila getting constantly irradiated while comforting her dying husband made my skin crawl."

People with terminal acute radiation poisoning are not, as a rule, hazardous to others. Lay intuition expects induced radiation, but that's not significant. All the radioactive contaminants were surely long before washed off him. Their daughter's birth defects were much more likely the result of exposure back in Chernobyl. The danger was more to the patients getting an infection.
posted by Ivan Fyodorovich at 8:55 AM on June 6, 2019 [3 favorites]

Correction: "So what she described would be like 1000 to 2000 times those... " Or 150 as I later wrote in the comment.
posted by Ivan Fyodorovich at 9:00 AM on June 6, 2019

How did Khomyuk know Lyudmila was pregnant when she found her in the hospital?
posted by Paul Slade at 12:05 AM on June 9, 2019

How did Khomyuk know Lyudmila was pregnant when she found her in the hospital?

Wasn't the clue that she was holding his hand on her belly?
posted by Dip Flash at 6:12 PM on June 9, 2019 [1 favorite]

For those who'd like an introduction to the RBMK design for a sense of how the mystery of the explosion will be explained, there are these introductory paragraphs from the Chernobyl section of James Mahaffey's excellent book, Atomic Accidents — A History of Nuclear Meltdowns and Disasters : From the Ozark Mountains to Fukushima:

There were some serious design flaws. The reactor core is big—a graphite cylinder 46 feet in diameter by 23 feet high. Each fuel assembly is 12 feet long, and the machine that automatically pulls one out and exchanges it for another requires a space 114 feet high over the top of the reactor. There was no practical way to construct a sealed containment building over this tall machine, so the world is protected from fission products in the reactor by a single barrier, a round, concrete lid, eight feet thick, held by gravity in the reactor room floor. A sheet-metal roof keeps rain off the equipment.

Western reactors use the “scram” system to rush all the controls into a reactor and shut it down as quickly as possible. It takes about three seconds to complete the scram on a General Electric BWR power reactor, from the instant of hitting the big red button to having the controls top out in the reactor core. The equivalent Soviet system is the AZ, or “Rapid Emergency Defense.” Push the big red AZ button, and it takes 20 seconds for the control rods to be completely in. A lot can happen in 20 seconds, but that is not the worst characteristic of a Soviet-style scram.

The control rods are as long as the reactor is high, but the active region in the middle of a control rod is only 16.4 feet long. The rest is just hollow tubes, at the top and bottom of the boron neutron-absorber section. At the bottom of each control rod is a rounded tip made of pure graphite, designed to act as a lubricant that will ensure smooth running of the rod in its metal tube under conditions that would ruin ordinary grease. If a control rod is withdrawn all the way, then the first thing that enters the core during an emergency shutdown is a big chunk of graphite. Putting additional graphite into the core increases the activity instead of decreasing it, so scramming from a condition of all-out rods does the opposite of what is desired for a long five seconds. If the reactor is critical and a shutdown is needed, the reactor goes supercritical until the active section of the rod is able to overcome the positive reactivity introduced by the graphite tip. If the reactor is supercritical when the rod is inserted, then the power rise proceeds at increased speed. Push the rods in one at a time, and this is only an irritation. There are 211 control rods in an RBMK. Put all of them in at once, and the reactivity will increase explosively. Under any normal operating condition, all rods are never out all the way.

Another bad characteristic of the RBMK reactors is the positive void coefficient. The neutrons are moderated down to optimum fission speed by the graphite, which has a very low tendency to scavenge neutrons out of the process. The coolant is water, which does scavenge neutrons, and the water runs through metal tubes perforating the reactor core. There is enough graphite to overcome the negative effects of the water and maintain criticality. If water is lost out of a tube or if it boils dry into steam, then the overall reactivity of the core is improved. The reactor goes supercritical, and the power level starts to rise exponentially. This is not good. In a PWR or a BWR, which use water for both coolant and moderator, if water is lost or turned to steam, the reactor shuts down instantly. In an RBMK, the power goes up with similar enthusiasm.

The first 3.23 feet of each control rod is a hollow metal tube, and it displaces the water out of the guide pipe as it is pushed in. From an all-out position, the control rod would first introduce graphite to the core, and then empty the cooling water out of the guide.

The water inlet tubes for the reactor all come up from the bottom, which is the logical way to do it, but fear of leakage from these tubes caused the engineers to design a large gallery under the reactor, sealed tightly and filled with water. The tubes run through the water tank, and this will dilute any fission products that happen to escape the fuel, get into the cooling system, and leak out through cracks or failed welds. This seemed like a good idea, but if the core ever melts it will fall directly into the water underneath and flash it into steam. Being tightly sealed with no way out makes rapidly derived steam into a bomb, sitting right under the core. The force of such a blast would be directed upward, making short work of the thin walls and ceiling above the reactor and pushing the big traveling crane above the refueling machine skyward. The mechanical engineers who designed the plant were good at anticipating bad welds but gave insufficient thought to what happens when a reactor runs away.

I particularly enjoyed the dry tone of that final sentence.
posted by Ivan Fyodorovich at 5:29 PM on June 10, 2019 [5 favorites]