Chernobyl on HBO

[arles]

I just finished watching the second episode and was confused by the ending. It appeared that with the dosimeter going crazy, the lights going out, and the sounds of breathing stopped (with closed caption) that the three guys on the suicide mission had failed. But obviously they didn’t because the thing didn’t blow up (in the real world). So I was looking to see if this was real or fictionalized. I found this interesting write up on individuals involved with the Chernobyl disaster. The three heroes were “forgotten” from the original official version.

In addition, on 28 April 1986, three men knowingly took on a likely suicide mission to prevent a steam explosion that would have destroyed an area from Kiev to Minsk, and would have cause the spread of lethal radiation across much of Europe.[28] Plant engineers Alexei Ananenko, Valeri Bespalov and Boris Baranov wore diving equipment and entered the reservoir tanks below the burning reactor, an area which had become filled with firefighting water and coolant water, to locate and open release valves to drain the water.[29] Scientists believe that, once the reactor melted through its concrete slab and plunged into the water, the steam explosion would have released many times more radiation into the atmosphere than the original explosion.[30] Despite severe risk, all three survived the mission, and in 2018 they were awarded the Order For Courage, Third Grade, by President of Ukraine Petro Poroshenko.[31] During the April 2018 ceremony, with the Chernobyl New Safe Confinement structure in the background, Poroshenko noted that the three men had been quickly forgotten at the time, with the Soviet news agency still hiding many of the details of the catastrophe, having reported that the three had all died and been buried in “tightly sealed zinc coffins.”[31] Ananenko and Bespalov received their awards in person while Baranov, who died in 2005, was awarded posthumously.

https://en.wikipedia.org/wiki/Individual_involvement_in_the_Chernobyl_disaster

[Broomstick]

@Pedro

People use “nuclear fizzle” to mean a nuclear weapons test that has a lower than expected yield. The conditions required for a nuclear explosion (a fission detonation) are not present in a reactor.

No, but “nuclear fizzle” and “maximum possible BOOM out of a Chernobyl type reactor” are within spitting distance of each other. Or so I’m told.

[SenorBeef]

That’s only because a nuclear fizzle can range down to almost nothing. A steam explosion would be on par with other big industrial accidents where chemical plants and such blow up. It would’ve probably been smaller than many. The contamination would be a real danger. Basically a dirty bomb.

[mistymage]

I watched both episodes with Mistermage and he kept sputtering through them. He especially thought it dumb the one General? drove the lead lined truck right up to the building to get a reading. Then he (husband) started spitting math at me like not only did I understand it but that I should either go back in time and tell the general the math formula or tell the writers if that bit was put in for license. He’s Level III NDT and I passed algebra 30 some years ago

[Broomstick]

@SenorBeef

That’s only because a nuclear fizzle can range down to almost nothing. A steam explosion would be on par with other big industrial accidents where chemical plants and such blow up. It would’ve probably been smaller than many. The contamination would be a real danger. Basically a dirty bomb.

A really big dirty bomb, explosive range *maybe *up into tens of kilotons, but at least the single-kiloton range (there have been non-nuclear explosions in the 1-4 kiloton range. Fortunately, they are not common).

Yes, Chernobyl could have been worse. How much worse I can’t say for sure, I’m just glad we didn’t find out the hard way.

[Pedro]

It could have been worse but that’s a matter of scale and conjecture. Going back to my initial post:

@SlackerInc

Right, but what Railer is referring to is the near-miss of a massive cataclysm that would have killed millions and rendered all of Eastern Europe uninhabitable. That was not something I realized was a possibility, much less a near-inevitability if they had not prevented it at the last moment.

This is wildly speculative (and played for dramatic effect in the show). I don’t think we were on the brink of disaster, an open core speweing radioactive material into the atmosphere and the surrounding environment is the disaster.

[SenorBeef]

@Broomstick

A really big dirty bomb, explosive range *maybe *up into tens of kilotons, but at least the single-kiloton range (there have been non-nuclear explosions in the 1-4 kiloton range. Fortunately, they are not common).

Do you have a source for this? Tens of kilotons is a huge, HUGE conventional explosion. Unprecedented by anything except volcanos, meteor impacts, and nuclear weapons. Was that seriously predicted of what could’ve happened at Chernobyl without the release valves?

[Broomstick]

I don’t have a cite to point to, although I remember reading one or two claims which, to be honest, I found to be “out there”. I don’t have enough knowledge to truly evaluate such claims. As I said, there are documented explosions by conventional explosive things up to single kiloton range. If someone claimed hundreds of kilotons I’d say they were full of it but 10? I dunno, maybe?

You’re right, it would be huge.

So far as I know there is no way you could get a nuclear explosion from a reactor core. So it would, indeed, have to be some sort of steam explosion powered by the heat generated by nuclear reactions, which is of course not a nuclear explosion.

[Baron_Greenback]

So, how dramatic and tense was the last scene in episode 2 of the semi-realistic fictional drama about Chernobyl then? Brrr, scary!

[SlackerInc]

Are we meant to understand that it was radiation that caused the lights to go out? Did these guys have some kind of shielding in their suits?

[EllisDee]

And how the hell did they survive into the 2000s?

[Lamoral]

The message I’m taking away from all the reading I’ve done recently about the accident is that humans can actually withstand and recover from high doses of radiation surprisingly well. They might need ongoing medical treatment for the rest of their lives afterwards, but it’s not the death sentence that I originally thought it was.

[Baron_Greenback]

@SlackerInc

Are we meant to understand that it was radiation that caused the lights to go out?

Maybe the big explosion and all the water around all that electrical stuff? I dunno

[SlackerInc]

@Lamoral

The message I’m taking away from all the reading I’ve done recently about the accident is that humans can actually withstand and recover from high doses of radiation surprisingly well. They might need ongoing medical treatment for the rest of their lives afterwards, but it’s not the death sentence that I originally thought it was.

Yeah, interesting. As I mentioned upthread, my grandfather took me on a Ukrainian river cruise (with a short segment in the Black Sea), and on our ship was an engineer who was at Chernobyl when the accident happened. This was about four years later, and I remember being impressed that he looked to be in perfect health.

[EllisDee]

@Baron_Greenback

Maybe the big explosion and all the water around all that electrical stuff? I dunno

I don’t recall any explosion in that scene. (They were asking about the flashlights going out on the divers in the water.)

[DPRK]

@Broomstick

So far as I know there is no way you could get a nuclear explosion from a reactor core. So it would, indeed, have to be some sort of steam explosion powered by the heat generated by nuclear reactions, which is of course not a nuclear explosion.

The only difference between an uncontrolled “nuclear reaction” and a “nuclear explosion” is how long the critical mass stays together in order to release energy via nuclear fission before blowing itself apart. Any sufficiently intense release of energy will result in an explosion. Little Boy featured highly enriched uranium, explosives to rapidly assemble a critical mass, and a tamper and neutron reflector around it to enhance the chain reaction effect and, even so, only a small fraction of the uranium underwent nuclear fission.

In a Chernobyl-type reactor, you don’t ever want any part of the core to go prompt critical because it will result in an uncontrollable exponential power rise with a short period. Now, exactly how much energy was released through nuclear reactions in the first or second explosion? 10 tons? One ton? (It obviously wasn’t “kilotons” or “megatons” of TNT.) I haven’t seen reports of the latest computer simulations, from the 2000s, that could answer that question more accurately.

[Baron_Greenback]

@EllisDee

I don’t recall any explosion in that scene. (They were asking about the flashlights going out on the divers in the water.)

Ah, yes. Indeed. :o

[Gray_Ghost]

@Broomstick

I don’t have a cite to point to, although I remember reading one or two claims which, to be honest, I found to be “out there”. I don’t have enough knowledge to truly evaluate such claims. As I said, there are documented explosions by conventional explosive things up to single kiloton range. If someone claimed hundreds of kilotons I’d say they were full of it but 10? I dunno, maybe?

You’re right, it would be huge.

So far as I know there is no way you could get a nuclear explosion from a reactor core. So it would, indeed, have to be some sort of steam explosion powered by the heat generated by nuclear reactions, which is of course not a nuclear explosion.

How big was the pool? I was back-of-the-beer-coaster thinking about the claim for the size of the steam explosion, and I got, just looking at the heat of vaporization for a water pool a hundred meters by 100 meters and 10 meters deep and the energy required to flash that to steam was on par with a few 10s of kilotons. Not that I think a melting core would do that, but I think the explosion would breach containment on Reactors 1-3, and we already know how hot graphite loves to burn.

Not a nuclear explosion, but one gigantic mess.

Aside, isn’t it possible to get a supercritical state, for at least a few doubling, for some configurations of highly enriched fuel reactors? That, I’d think, would count as a nuclear explosion, if not what was actually present or possible at Chernobyl. My favorite fizzle story is the test from LLNL, that didn’t even vaporize the test tower. So they made the next test tower shorter.

[Pedro]

@SlackerInc

Are we meant to understand that it was radiation that caused the lights to go out?

It’s not clear to me why it would. I’m also wondering what caused the destruction of the helicopter rotor.

@DPRK

In a Chernobyl-type reactor, you don’t ever want any part of the core to go prompt critical because it will result in an uncontrollable exponential power rise with a short period. Now, exactly how much energy was released through nuclear reactions in the first or second explosion? 10 tons? One ton? (It obviously wasn’t “kilotons” or “megatons” of TNT.) I haven’t seen reports of the latest computer simulations, from the 2000s, that could answer that question more accurately.

Right, the explosive power is a function of energy and also time. SL-1 was estimated to be 32 kg of TNT, still a long way from 1 ton.

I didn’t think it possible but some sources do suggest a nuclear explosion in those ranges as the direct cause for both explosions at Chernobyl (one or the other).

Legasov was at a loss to explain “how an RBMK reactor explodes” in the episode, I enjoyed that detail.

[EllisDee]

@Pedro

I’m also wondering what caused the destruction of the helicopter rotor.

While watching that confused me too so I rewound it several times and finally ran it in slow motion. It looked to me like the pilot was incapacitated in some way (blinded?) when flying over the tower so the helicopter started listing, and then you could just barely see that the rotor hit a wire that snapped the rotor, at which point it dropped to the ground like a rock.