What if chernobyl were to explode?

[Arugela]

Could Chernobyl turn into a dirty bomb if an accident of any kind hit it. Or is it relatively safe? How far could an explosion of any type make a dirty bomb or similar problems?

If the soil were disturbed by anything how far could it go? What else could happen to it and the surrounding area to cause harm?

Is it safe to assume it can't do much to the rest of the region and would only spread locally or can it be worse?

In fact if it's closer to Russia can it hit Russia or Belarus as it's close to the border. I would think it could be dangerous if it was struck somehow. There are supposedly apartments getting hit from one side or the other with the helicopters and possibly anti air ordinance interacting(not to mention possible direct fighting around the plant.). Is any of this in that area? Or is that all farther away?

I'm assuming it would take a larger hit to do more damage, but how much would it take to start causing problems. Could vehicles moving in the area cause problems? Can they track the radiation around as they move because of the preexisting soil radiation?

Edited February 26, 2022 by Arugela

[K^2]

As we are seeing right now, just having too much movement in the area is kicking up the dust and increasing levels of radiation. If you start detonating explosives in the area, that will get worse, so clearly, some amount of damage can be done.

As for the power plant itself, reactors 1-3 have been in the process of getting decommissioned since 2015. I would imagine, removing fuel and any contaminated materials would be the first step, which means, they probably present very little danger right now even if bombed.

The remains of reactor 4 are still buried within the sarcophagus. It would take significant effort to crack the concrete around it, but I suppose, it is technically possible to clear the concrete structure, then set up a detonation to spread radiation. But it would be a major effort. Not something that's going to happen by accident, and not really something that would make sense as an attack for a nation that has access to nukes. It wouldn't look like an accident or work of some local groups either. So it would make absolutely no sense to mess with the No. 4 right now for anyone.

Kicking up the dust from irradiated environment around the plant is really the biggest danger. It's hard to say how serious this is and how far downwind the radiation might travel. I am very confident that it can't get worse than during the peak of disaster, so no major cities should be in any sort of danger, but the idea does make me a little nervous. So if it's all the same to everyone involved, when the time comes to it, if they can avoid shelling the area, I would appreciate it.

I also don't think it's any good for the soldiers present there. The data that's being publicly shared shows radiation levels at 65,500 nSv/h, which isn't a lot. But in an ironic twist, as these familiar with computer hardware probably already realized, the reason this number is shown is because it's hitting a 16 bit limit (rounded to 100nSv/h), meaning it's actually saturated at maximum value the sensor can show. Based on the fact that the readings jumped from zero to max value over a single time bin, and on the fact that other agencies have picked up on radiation increase in the area, it's safe to say that the actual radiation levels in immediate area are a lot higher and soldiers holding the area are probably getting unhealthy quantities of radiation. Whether it's enough to cause lasting damage remains to be seen, and maybe it's still safer than risks of acute led poisoning elsewhere.

[RCgothic]

Whilst Chernobyl units 1-3 have been defuelled, the highly radioactive graphite cores remain, and could catch fire if exposed to air and ignited, say by a bomb.

Unit 4 does still have nuclear materials present. Fision is unlikely to restart, but the remains of the core would still be flammable and the result would be much more radioactive.

A fire started in any of these cores by a bomb would necessarily be accompanied by a large beach of containment. This would not be good.

Without a nuclear meltdown ongoing it may be easier to extinguish burning cores. In the middle of a warzone, that would make it harder.

Bombing them would not be wise in any case. Russia is downwind of Ukraine.

 

Other than decommissioned Chernobyl, there are currently 4 active nuclear plants in Ukraine. It's unclear how these would react to a prolonged grid disconnection. It would depend on the ability of the staff to start and supply the generators. The staff could flee, the generators could be damaged, fuel supplies could be hard to come by. The UK's AGRs could withstand natural convection cooling for a substantial period. PWRs generally can't. RMBKs are a denser graphite core than the AGRs. I'd lean towards "can't" if there are any of those still operating.

A PWR overheating would probably go like Fukushima. An RMBK would also catch fire, but probably not explode like Chernobyl.

[DDE]

3 hours ago, K^2 said:

Not something that's going to happen by accident, and not really something that would make sense as an attack for a nation that has access to nukes. It wouldn't look like an accident or work of some local groups either.

More importantly, most of the fallout would go completely the wrong way.

Meanwhile, the notion of deliberate meltdowns was brought up by a seemingly genuine account of the Zaporozhskaya NEP last autumn, and made a lot of rounds on the Russian web.

https://t.me/zaes_energoatom/498

We've seen a whole war started under a much flimsier pretext. However, the post feels a bit tongue-in-cheek.

22 minutes ago, RCgothic said:

Other than decommissioned Chernobyl, there are currently 4 active nuclear plants in Ukraine. It's unclear how these would react to a prolonged grid disconnection. It would depend on the ability of the staff to start and supply the generators. The staff could flee, the generators could be damaged, fuel supplies could be hard to come by.

We'll soon find out. Twitter seems down right this very moment so I don't have end-of-day maps to check, but I believe the above-mentioned NEP with its six reactors has already changed hands.

Ultimately, @Arugela, you're a little bit late to the party - the fighting has already moved further south, Chernobyl was just a stepping stone. US says the Russians are holding the sarcophagus crew hostage, the Russians say the Ukranian force there has flipped and is cooperating in keeping the site secure.

Additionally, Russian troops have always emphasized CBRN defense training with alarming gusto, so decontamination after passage should not be a significant problem.

https://www.thedrive.com/the-war-zone/24906/russia-uses-these-crazy-antique-jet-engine-equipped-trucks-to-blast-away-chemical-agents

[Shpaget]

4 hours ago, K^2 said:

But in an ironic twist, as these familiar with computer hardware probably already realized, the reason this number is shown is because it's hitting a 16 bit limit (rounded to 100nSv/h), meaning it's actually saturated at maximum value the sensor can show.

History repeats itself.

-What does the dosimeter say?
-3,6 roentgen, but that's as high as the meter...
-3,6. Not great, not terrible.

[DDE]

1 hour ago, Shpaget said:

-3,6. Not great, not terrible.

Actual history, I believe, was,

"That's as high as it goes."

"Where's the one with greater range?"

"In the staff room. Which is locked."

"And the key?"

"Under six feet of rubble."

However, by that time, the witnesses could taste the air ionization and feel it be thick with radioactive noble gasses.

Edit: I've read through Medvedev; it's the room itself that got trashed.

Spoiler

Прежде  всего   надо  выяснить радиационную  обстановку. Перевозченко побежал,  поскальзываясь  на  осколках  стекол,  к  помещению  щита   РБ,  к Горбаченко.
     Дозиметрист был бледен, но собран.
     - Какой фон, Коля?  - спросил Перевозченко.  Лицо его  уже горело бурым огнем.
     - Да вот... На диапазоне тысяча микрорентген в  секунду зашкал, панели
четвертого блока погасли...- Горбаченко виновато улыбнулся.- Будем  считать,
что пять рентген в час. Но, похоже, много больше...
     - Что ж вы даже приборами не разжились?
     - Да  был  вот прибор  на тысячу рентген, но сгорел.  Второй в каптерке
закрыт.  Ключ  у Красножона.  Только  я  смотрел,  та каптерка в  завале. Не
подступишься. Сейчас пойду с Паламарчуком Шашенка искать. Не откликается из шестьсот четвертого...

 

Edited February 26, 2022 by DDE

[K^2]

45 minutes ago, DDE said:

Twitter seems down right this very moment

I haven't noticed any outages this side of the pond. I've heard that there might be some planned disruptions. Possibly time to start using VPN and/or onion networks. It's great to know that people are trying to get, um... a broader spectrum of information sources, though. 

[kerbiloid]

The reactor building should withstand a passenger plane hit, but according to the numerous movies, we should be afraid of activization of various forms of paranormal activity.

Spoiler

 

[Scotius]

I would be very unhappy if some butter-fingered sołdat triggered The Second Event, and turned parts of Ukraine and Belarus into The Zone. War is raging too close as it is - I don't want to additionally worry about blowouts, occasional mutants and deranged, heavily armed Stalkers.

[Nuke]

russia seems to have made securing the reactor facilities a priority. i cant imagine that any country interested in taking over another would do any differently. if we had to invade north korea, i think their nuclear facilities would also be priority targets. i think they are off the board unless the ukrainians plan on taking it back. why anyone would want a broken down old reactor complex is beyond me. whoever owns it has to foot the bills. i worry that russia might attempt to demolish it if they cant hold it. i dont know what the feasibility of turning a busted old powerplant into a nuke factory is, but its something i dont think anyone wants to find out. 

[RCgothic]

I think the plant was incidental. The Chernobyl Exclusion Zone was just something that had to be captured to secure a route to Kyiv.

[DDE]

9 hours ago, Nuke said:

dont know what the feasibility of turning a busted old powerplant into a nuke factory is,

The biggest factor is usually the ability to refuel the reactor without shutting it down, because plutonium harvesting is basically done from underused fuel rods. RMBKs - those found in Chernobyl - allow the fuel rods to be yanked out of the top plate of the reactor at any time, and are directly derived from specialist plutonium generation reactors. All of Ukraine's remaining reactors are VVERs, a Soviet counterpart to PWRs, which are safer in both the usual sense and the proliferation sense because they operate under pressure.

That leaves you with the need to chemically extract plutonium from a mixture of hideously radioactive decay products... whereas Ukraine doesn't even have a native reactor fuel production industry.

[kerbiloid]

10 hours ago, Scotius said:

I don't want to additionally worry about blowouts, occasional mutants and deranged, heavily armed Stalkers.

What about Sapkowski, Wiedzmin, fantasy romantics?

[DDE]

1 hour ago, kerbiloid said:

fantasy romantics

Ain't all fun and roses either

[RCgothic]

3 hours ago, DDE said:

The biggest factor is usually the ability to refuel the reactor without shutting it down, because plutonium harvesting is basically done from underused fuel rods. RMBKs - those found in Chernobyl - allow the fuel rods to be yanked out of the top plate of the reactor at any time, and are directly derived from specialist plutonium generation reactors. All of Ukraine's remaining reactors are VVERs, a Soviet counterpart to PWRs, which are safer in both the usual sense and the proliferation sense because they operate under pressure.

That leaves you with the need to chemically extract plutonium from a mixture of hideously radioactive decay products... whereas Ukraine doesn't even have a native reactor fuel production industry.

To add to this, in pressurised water reactors like PWR and VVT the coolant and moderator consists of water. Water is also a neutron shield, so the fuel rods need to be placed close together so that the neutrons can interact before the water absorbs them. This dense placement means that there isn't space to individually seal each fuel channel. In order to refuel the core the entire top of the pressure vessel is removed whilst the reactor is inactive. So refuelling is a big job only done occasionally during so-called "outages".

In graphite moderated reactors like Magnox, AGR and RMBK, a large proportion of the water is replaced by graphite. Graphite is not a neutron shield, so the fuel channels are spaced further apart and individually sealed. A specialised fuelling machine can lock onto the top of the reactor and exchange fuel rods without dismantling the core pressure vessel. In theory this means the reactors don't need to be shut down for fuel exchanges to take place and "outages" are unnecessary. It also means partially burned plutonium containing fuel can be extracted without stopping the entire reactor.

The AGRs never really got this working unfortunately, as gas dynamics during the extraction process caused the fuel rods to vibrate and shatter during tests. This seriously affected their commercial viability compared to PWRs. AGRs are physically much bigger and have complicated fuel handling arrangements. If they also still have to have outages then the main tradeoff has failed.

RMBKs were just a bad idea. Unlike AGR and Magnox, they were water cooled which provides what's known as a positive void coefficient. If a little water gets too hot it boils, forming voids which don't shield as much, so the reaction increases, so it gets hotter, so more voids form. And RMBKs were filled with a liquid which could explosively vaporise. AGRs and Magnox were cooked by gas. It can't explosively vaporise because it's already a vapor. And unlike PWRs, in RMBKs there's a separate graphite moderator. The moderator is what catalyses the reaction. In a PWR of the water boils the shielding is lost, but the moderator is also lost, so there's no net gain.

RMBKs, AGRs and Magnox didn't operate with secondary containment. In water cooled reactors if the steel pressure vessels were breached a crack would rapidly less to complete failure. Secondary containment is required to contain and quench the steam that would rapidly boil as the pressure keeping it liquid is lost. AGRs and Magnox had concrete pressure vessels. These would just leak mildly radioactive gas if they failed. The gas can't vaporise again, and there's an emergency supply of gas to back fill any losses. The reactors would be powered down, depressurised and a repair made without a gross failure. RMBKs... Yeah, they really needed some secondary containment.

Concrete primary or secondary containment is extremely sturdy. Airliners would probably bounce off without causing significant damage (although AGRs would be vulnerable if the fuelling machine above the concrete structures were damaged whilst connected to the reactor - they'd leak substantially through the damaged standpipe). Concrete containments would not stand up to bunker-busting bombs however.

Edited February 27, 2022 by RCgothic

[Arugela]

23 hours ago, Nuke said:

russia seems to have made securing the reactor facilities a priority. i cant imagine that any country interested in taking over another would do any differently. if we had to invade north korea, i think their nuclear facilities would also be priority targets. i think they are off the board unless the ukrainians plan on taking it back. why anyone would want a broken down old reactor complex is beyond me. whoever owns it has to foot the bills. i worry that russia might attempt to demolish it if they cant hold it. i dont know what the feasibility of turning a busted old powerplant into a nuke factory is, but its something i dont think anyone wants to find out. 

[snip]

Out of morbid curiosity, could chernobyl be fixed and used again. Do we have the means now to get it working again without side effects?

Edited February 27, 2022 by Vanamonde
Avoid politics, please.

[kerbiloid]

3 of 4 are just unloaded, afaik. So, probably can be repaired and used again.

The only question why restart the obsolete design.

It needs parts and so on, so would face logistical problems.

[DDE]

27 minutes ago, Arugela said:

Out of morbid curiosity, could chernobyl be fixed and used again. Do we have the means now to get it working again without side effects?

The other units can probably be reconditioned, rebuilt and kept in operation for quite a while.

№4, meanwhile... this the top plate of the reactor:

As you can see, it's taken quite a long flight before getting stuck into the old pressure vessel, sideways. The entire building and the original 1986 Shelter built around it are structurally unstable. The top plate falling over can lead to a nasty dust generation event.

[Nuke]

7 hours ago, Arugela said:

Out of morbid curiosity, could chernobyl be fixed and used again. Do we have the means now to get it working again without side effects?

i was mostly speaking of the tactical rather than the political. just so were clear. its an important chess piece to take off the board. both sides probibly want the decommissioning to go on as planned. but then again, things happen in war. 

Edited February 27, 2022 by Vanamonde

[Vanamonde]

Some comments removed. Remember to leave politics out of discussions on this forum, please. 

[Starhawk]

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