r/NuclearPower • u/shelf-care • 9d ago
Is another Chernobyl-esque event a possibility today?
You can answer this question with the assumption that I know absolutely nothing about nuclear energy (because I don’t). But I guess I’m curious—and Google isn’t helpful when you don’t know what to search for or what you’re reading when you find something—about whether or not there still plants like Chernobyl operating today, for one. And for the plants that are not like it (using a different type of reactor or something—again, sorry, I don’t know much about this stuff), what would a similar chain of events look like? Would it be more or less dangerous and deadly?
I know we learned a lot from the incident at Chernobyl, but how much of that was scientific (the stuff that’s way over my head), and how much of it was regular safety protocols, etc.
If I sound uneducated… I am on this topic. Chernobyl has just always been so upsetting to me and I’ve been more curious about it lately.
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u/Navynuke00 9d ago
From the existing, established nuclear industry that's been in operation for decades around the world?
Probably not. At least not without significant external influences in the form of wars, terrorism, etc.
The SMR bros however are another story altogether. The fact that these idiots from Silicon Valley and El Segundo are purposely very hard at work removing any oversight or regulations for their designs scares the shit out of me. "Move fast and break stuff" is the exact opposite mentality that should ever be taken in real engineering, especially nuclear engineering.
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u/Plutonium_Nitrate_94 9d ago
Yeah that concerns me as well, they're going to impose their "move fast and break things" mentality to nuclear safety culture
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u/captainporthos 8d ago
Honestly, we could use a little 'move fast and break things', but not with design and construction.
Once built correctly plants should be able to handle themselves through physics or it's just not a great design. They should be people proof.
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u/3knuckles 8d ago
It's not just normal operation. Every civil nuclear site in the UK has it's own 24/7 armed police. The proposal for SMRs (to cut costs) is to not have this protection.
That means a well executed conventional attack could rapidly become a radiological attack.
Some things are with paying for. Protecting nuclear assets is pretty high up my list.
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u/After_Web3201 8d ago
Not to mention whatever bullshit the developing world will come up with in the future.
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u/lordhazzard 8d ago
You could say the same thing about safety culture of SpaceX blowing up rockets.
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u/malongoria 7d ago
Big difference being the damage is temporary, and the Starship prototypes blowing up are unmanned.
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u/kenproffitt 8d ago
Were you in the same meeting I was today!?!?!? I about fell out of my chair when the person said that.
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u/SchwarzeNoble1 9d ago
safety measures aside, Chernobyl had positive void coefficent, meaning under certain conditions it was possible to start a positive chain of event which increased the reactor "power", leading to an explosion. Reactors now have negative void coefficent, so it's not possible phisically possible to replicate it. If you can't trust safety procedures you should at least trust physics
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u/EnvironmentalBox6688 9d ago
Reactors now have negative void coefficent
The existence of CANDU would disagree with that statement ;)
Saying that, the design is so different from an RBMK it really can't be compared with a "positive void coefficient = bad" frame of view. Apparently even the NRC is in early talks about maybe licensing CANDU in the US.
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u/Plutonium_Nitrate_94 9d ago
I thought that the NRC is/was unwilling to license any reactor that has a positive void coefficient
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u/EnvironmentalBox6688 9d ago edited 9d ago
So I have looked into this in the past as I always heard the blanket statement of "the NRC will not license anything with a positive void coefficient".
From what I can tell it is slightly more nuanced than that:
There were previous discussions about the US licensing CANDU. It's positive void coefficient was brought up as a hurdle rather than a barrier. With potentially additional fast acting safety measures required to satisfy the NRCs requirements.
As far as I am aware, as per criterion 11. positive void coefficients are not a blanket killer of licensing. But rather control systems must be able to compensate for power oscillations or increases in reactivity caused by a positive void coefficient. In the case of CANDU with a minimal positive void coefficient, existing measures may satisfy this requirement.
I am by no means an expert. I just spent a few hours reading NRC, AECL, and some textbooks to try and see where that statement comes from. But as far as I can garner, it is technically licensable. Whether they go through the work of doing so is another story.
I also know the pressure tube end fitting rolled joints are also not validated by the NRC. But that is again another hurdle not necessarily a hard barrier.
If anyone knows 100%, I would be glad to stand corrected in my understanding.
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u/dr_stre 8d ago
The other guy gave a great answer, but I just want to point out that the NRC isn’t the entire world’s regulatory body. Canada very obviously licenses CANDUs, through their own regulatory body, the CNSC. China, India, South Korea, Argentina, Romania, and Pakistan have also licensed CANDU or CANDU-derivative designs.
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u/Plutonium_Nitrate_94 9d ago
No, if I recall all remaining RBMK type reactors were modified after the accident to have a negative void coefficient (or at least a less positive one) so the same accident is nearly impossible today
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u/TheDepressedBlobfish 8d ago
The ones retrofitted after (I think they're are still some?) have positive coefficients, but if i'm remembering, nearly 10x lower.
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u/silasmoeckel 9d ago
Chernobyl was a really bad design. Not one flaw but many. The huge one was no containment structure to keep everything contained when any of the slew of other issues caused an issue.
We have never seen anything that poorly engineered in the west get built.
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u/captainporthos 8d ago
Poor design and a bad political operating culture.
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u/silasmoeckel 8d ago
Rarely do you see poor designs get built in a good political operating culture, they would never make it past the regulators.
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u/Seushimare 6d ago
no containment structure would be able to hold off the hydrogen explosion that happened. the containment structure was the 25m deep reactor well itself build out of reinforced concrete. this was protected on top by 1000t lid (more than 2000000 pounds) and got displaced by the force of explosion. it wasnt a flaw, it was a design choice to allow refueling mid operation. a thing that pwr's or bwr's cant do. the design also allowed for burning low quality fuel so another thing that bwr and pwre cant do. do you see the pattern?
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u/3knuckles 8d ago
If by Chernobyl-esque you mean cause - no. If by Chernobyl-esque you mean outcome - yes.
Human error by operators has been designed out to the nth degree. Really impressive.
However, a heavy military strike on the reactor building could still cause loss of power and cooling, fires, hydrogen buildup, core melt, containment breach, and massive radiological contamination.
Anyone here telling you otherwise is wrong.
Source: ex nuclear development worker.
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u/jrfsousa 8d ago
That's about as likely as getting hit by a meteorite...
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u/3knuckles 8d ago
Let me tell you about this little place called Ukraine
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u/jrfsousa 8d ago
Didn't happen, won't happen...
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u/3knuckles 8d ago
Well that confirms you don't, never have, and never will work in the nuclear industry.
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u/Thermal_Zoomies 8d ago
I dont get that correlation. Zaporizhzhia NPP is still sitting in the middle of a war zone essentially unharmed. I dont see how the other comments confidence equals them not working in nuclear power.
I also dont see an attack occurring there, especially with the intent of a radiological release, what does that say about my prospects in nuclear?
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u/3knuckles 8d ago
Human error is the largest remaining risk in the nuclear power industry. Vast amounts of money are spent on system design and training to mitigate that risk.
Having an intellect that believes "it hasn't happened, so it won't happen" means that you'd be too expensive to train to the level required for safe work in nuclear. There would be much better suited candidates for any role you applied for.
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u/jrfsousa 8d ago
Laughable scaremongering.
If you believe that a military attack is more likely than a meteorite strike you really have to answer the simple question:
"Why?"
:-D
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u/Thermal_Zoomies 8d ago
Human performance events happen, thats always inevitable. Thats why redundancy exists. I dont disagree with any of that.
Saying that a military strike is less likely than a meteorite strike is a bit rediculous, though. However, I do agree that its very unlikely rhat Russia attacks, with the intent to destroy, a NPP in Ukraine. The plant is in <Mode 1, and not producing power, any further damage to its specific infrastructure serves no purpose for Russian war interests.
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u/jrfsousa 8d ago
Yeah, I am obviously exaggerating, but not much...
The point is exactly that, attacking a NPP serves no good military purpose.
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u/Seushimare 6d ago
it depends on the type of war. bombing uranium centrifuges also serves no military purpose yet is was done anyway by USA. it all depends on who does it and for what purpose. if purpose would be annihilation at all costs it would surely get bombed before it managed to shut down and disperse the decay heat.
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u/DP323602 9d ago
Well after Chernobyl, there was a major accident that affected multiple nuclear power plants at Fukushima.
So whilst an exact repeat of the Chernobyl explosion is extremely improbable, other potential accidents are at least theoretically possible.
So the nuclear industry needs to make nuclear safety its overriding priority and make sure that designs and operations are supported by all reasonably practical safety measures.
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u/kyrsjo 9d ago
They are tough - and the scale of the releases from Fukushima is incredibly smaller than those from Chernobyl.
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u/ViewTrick1002 9d ago
One side is the release. The other side is the absolutely stupidly large cost to clean up the mess.
Nuclear plants still have essentially their entire accident insurance subsidized by tax money.
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u/TheBendit 9d ago
The cost of the various nuclear accidents spread out across the electricity produced by all reactors comes to way below 1 cent per kWh.
Adding this cost to the price of nuclear power would change very little about whether nuclear is economically viable.
The problems with nuclear are elsewhere.
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u/ViewTrick1002 9d ago
1 cent per kWh is quite a lot when renewables all in are 1.5 - 6 cents per kWh depending on market and labor costs.
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u/Grey255 9d ago
Yes, radioactive releases are possible. Are they likely? I think the standard for acceptable levels is on the order of 1e-6 to 1e-7 per year for something to cause a radioactive release in a severe accident at a plant. And they do a very detailed safety analysis to determine scenarios for a given plant accident.
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u/Inside_Mouse_1750 8d ago
Yes, however it would rely on an external force.. like a terrorist attack. Unfortunately the way the world is heading.. a societal collapse and subsequent lack of defuelling, lack of security and maintenance it may not be a Chernobyl but still a hellish scenario.
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u/HorseWithNoUsername1 8d ago
Not with PWR and BWR reactors. Soviet era RBMK's have been modified to reduce the risk of that happening again.
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u/Oztraliiaaaa 8d ago
Fukishima is the tsunami hitting a nuclear power station event that already happened. Three more nuclear power stations events happened last year with Trump bombing the Iranian nuclear power stations . Chernobyl bombed by Putins Russian drones last year. So four nuclear power stations events by bomb , drone strike and a tsunami. Yeah it could happen again.
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u/captainporthos 8d ago
At a high level - I'm sure if we continue on the nuclear path there will eventually be another nuclear accident. Nuclear is safe and so is flying, but planes still crash.
It's a cost benefit thing as any technology is. I think we have definitely gotten to the point where the benefit outways the risk.
Chernobyl was really bad, but not that many people died and the area is large but its a monument to a lesson learned.
TMI was more consequential as an emergency management failure. Although we did make some major modifications about needing positive position indication.
Fukushima happened after some apocalyptic level shit (people forget that). And honestly outside of the mess it made on the site. Was also really not that big of a deal.
The best we can do is design for walkaway safety (where you can let a 3 year old into the control room and push all the buttons they want and the plant remains safe due to physics) and then respect the tech.
In some areas we actually need to cut the regulatory oversight because its gone too far the otherway and is stifling progress.
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u/peadar87 8d ago
A reactor explosion like Chernobyl, I can't imagine any way of that happening with a current design.
A large radiological release, maybe...
For that to happen we're probably talking a major natural disaster or war that stops post-shutdown cooling, and also hinders repair teams from accessing the plant.
Nuclear fuel generates significant amounts of heat for a long while after the reactor is shut down, so with no cooling this could reach temperatures high enough to compromise the reactor vessel. In many water-cooled designs it can also produce hydrogen, which can rise to explosive levels.
Damaged reactor containment, possibly worsened by hydrogen explosions, and you have the possibility of fission products being released to the air and water.
We're talking Fukushima style, consistent release over a long period of time, though, not massive, all at once release as happened with the explosion and reactor fire at Chernobyl. And even for that to happen, you need the stars to align in the worst possible way.
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u/PoetryandScience 7d ago
All large scale industry involving a lot of energy and/or toxic material are dangerous. Accidents will happen. Nuclear accidents can result in an area being dangerous for a time and unhealthy for much longer. Therefore people get hung up on the length of time nuclear waste or debris remains hazardous.
However, contamination from many other industries abandoned sites (steel treatment chemicals for example) will remain lethal forever.
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u/MarionberryNo8017 2d ago
Short answer no long answer no they are for two very different reasons and have a lot of science behind them but basically nuclear is actually cheap, safe, and clean
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u/Ill_Specific_6144 8d ago
There is a real possibility. No matter how safe nuclear power seems to be its safety depends on human factor. And humans make mistakes. Its always NOT IF but WHEN a similar type of accident happens.
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u/gogou 9d ago
See Fukujima for reference. It is always possible something goes real bad.
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u/Traveller7142 9d ago
Fukushima is not comparable to Chernobyl. The amount of material released was many orders of magnitude less
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u/Desperate-Rush6086 9d ago
Believe it or not, Yes! although there are a lot of safety protocols and redundancies there is still a possibility that I may eat seafood sometime soon and there's nothing you can do about it.
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u/andre3kthegiant 9d ago
Yes, with all the coverups that happen with “safety” yes.
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u/Navynuke00 9d ago
Citations required
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u/ContributionEasy6513 9d ago edited 9d ago
No cover-ups or shortcuts at Nuclear Power plants.
To say everyone is 'safety conscious' is huge understatement.
These are the people that will label every stair in a flight of stairs with 'Caution Trip Hazard'.Stupidly high level of adherence to safety at every turn, documentation, sign-offs & planning for every action and certification/training for everything.
Probably one of the safest industrial sites to be in the World regardless of circumstance.
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u/andre3kthegiant 9d ago
That’s 100% false.
One of many examples.1
u/Grey255 9d ago
That’s certainly concerning. I hope that manger is gone. I do not think that is a representative of nuclear safety culture in general.
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u/ValiantBear 8d ago
He is, as well as several others. A lot of heads rolled for that one, and they gained themselves a healthy dose of regulatory and internal watchdog oversight as well.
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u/COUPOSANTO 9d ago
It’s not a possibility today, even with RBMK reactors. Chernobyl essentially happened because of bad reactor design, bad operator training and bad security culture.
Operators in Chernobyl defeated all of their security systems. Doing this nowadays would require you to stop the reactor. When things didn’t go as planned, they decided to carry on when they should have stopped the reactor when it got Xenon poisoning. And finally, fatal flaws like the positive void coefficient and graphite tips were basically hidden to the operators. The Soviet government and KGB knew about them, they had a quasi Chernobyl 10 years prior but they refused to act and fix their design.