What would happen to Nuclear Power Stations if…

What would happen to Nuclear Power Stations if…

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105.4

Original Poster:

4,214 posts

78 months

Friday 28th January 2022
quotequote all
99.9% of the population ceased to exist overnight?

Yes, I know. It’s a completely unlikely scenario, but crap like this does drift though my tiny little mind every so often.

From my very rudimentary understanding of nuclear fusion, the fuel rods are bathed in water? Water that would eventually evaporate, causing a situation that ‘wasn’t great, but isn’t horrifying’.

Could your average Joe with almost zero knowledge of the operation of a nuclear power station gain entry to the control room and save the day? Or would their meddling cause things to go ‘boom’?

As an aside, is there any more catastrophic dilemmas that would await what would be left of mankind? Would Porton Down be a ticking time bomb? What would happen if all the animals were released from zoos?

Please feel free to include your own nightmarish scenarios.

boxy but good

2,826 posts

152 months

Friday 28th January 2022
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Have you been watching 'The Simpsons' again ???


spin

WarrenB

2,616 posts

125 months

Friday 28th January 2022
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105.4 said:
Please feel free to include your own nightmarish scenarios.
Impossible, but, what would happen if the internet was just 'turned off'? No emails, no google, just back to phone calls, letters and books.

otolith

59,051 posts

211 months

Friday 28th January 2022
quotequote all
The pools full of rods are housing spent fuel. The water cools them and blocks the radiation. If they were dry, you would probably not want to enter the room, but I’m not sure anything particularly catastrophic would happen.

I think an unattended reactor would eventually just shut down.

anonymous-user

61 months

Friday 28th January 2022
quotequote all
The reactors would shut themselves down in the event of a problem - unless someone had done something truly stupid like disabling the safety systems.

Chernobyl wouldn’t have happened if the safety systems hadn’t been manually disabled so that the operators could try and force through a safety check. Irony…..

105.4

Original Poster:

4,214 posts

78 months

Friday 28th January 2022
quotequote all
WarrenB said:
Impossible, but, what would happen if the internet was just 'turned off'? No emails, no google, just back to phone calls, letters and books.
Well, I think it would be impossible for me to do my job. I’d have no means of downloading the data required to find out my workload for the day. No means of certifying what work had been done, or sending EoD results through. I’m sure there’s procedures in place to get around such problems, but they’d be above my pay grade.

Besides that, (and the lack of freely available porn), I think I’d quite like it for a couple of weeks.

We may even get to find this out for real this Spring anyway.

valiant

11,332 posts

167 months

Friday 28th January 2022
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Surely they have safety systems in place that’d automatically shut things down if the needles started to move dangerously into the red and no corrective action was taken. I’d also figure that a remaining bloke still couldn’t just walk in an start fiddling with stuff.

Besides only 0.01% of the population is left which means we’re all dead so fk ‘em.

105.4

Original Poster:

4,214 posts

78 months

Friday 28th January 2022
quotequote all
valiant said:
Besides only 0.01% of the population is left which means we’re all dead so fk ‘em.
Would certain satellites fall from the sky?

What would happen with medical procedures and medicines? Food production? Ships at sea carrying oil or chemicals?

8 million people left of the planet still sounds like a lot though?


edited to add;

I’m wrong. It isn’t a lot. It’s only 10% of the UK population spread across the entire globe !


otolith

59,051 posts

211 months

Friday 28th January 2022
quotequote all
WarrenB said:
Impossible, but, what would happen if the internet was just 'turned off'? No emails, no google, just back to phone calls, letters and books.
Not altogether impossible.

https://www.newscientist.com/article/2150350-a-tec...

xx99xx

2,249 posts

80 months

Friday 28th January 2022
quotequote all
Alternative answer, nuclear power stations would shut down because there would be no need for them if 99.9% of population disappeared.

A few hundred people could keep the national grid going from solar and wind to serve the few thousand people left.

gotoPzero

18,172 posts

196 months

otolith

59,051 posts

211 months

Friday 28th January 2022
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gotoPzero said:
https://youtu.be/F7QRsx9lbBU

Mr Pointy

11,836 posts

166 months

Friday 28th January 2022
quotequote all
xx99xx said:
Alternative answer, nuclear power stations would shut down because there would be no need for them if 99.9% of population disappeared.

A few hundred people could keep the national grid going from solar and wind to serve the few thousand people left.
It takes more than a few hundred people just to service the wind farms we have now, let alone the thousands needed to keep the distribution system going.

beambeam1

1,318 posts

50 months

Friday 28th January 2022
quotequote all
105.4 said:
Yes, I know. It’s a completely unlikely scenario, but crap like this does drift though my tiny little mind every so often.
Sounds like you need some Kurzsegaht in your life! Great YT channel that ponders and theorises scenarios like yours: https://www.youtube.com/watch?v=JyECrGp-Sw8&t=...

Gary C

13,167 posts

186 months

Saturday 29th January 2022
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So at some point the reactors would trip. Lots of reasons for that to happen from faults to blocking coolers.

Rods would go in and the automated cooling systems would cool the reactor down.

What happens next depends.

Lets say its the grid that takes it off (as stations trip, the grid would collapse with the same result) and then the stations would be on backup generation. Each station has a lot of fuel to run the backups, but their design mission time is about 24 hours and even thought they can last much longer, they also assume that some equipment is shutdown as the requirements for cooling reduce. With no people, all systems would continue to run using more fuel than anticipated.

Haven't worked it out (its written down somewhere), but eventually the backup generators would stop and the cooling systems would shutdown.

Now, a reactor thats been shutdown for, lets say 7 days, is still producing about 5-10MW of heat and will begin to warm up. Eventually in theory some reactors can go critical again if they warm up enough and that would mean a meltdown.

Big cores such as AGR's heat quite slowly but have a positive moderator coefficient whereas most water reactors have a much smaller core and thus heat up quicker but have a self regulating negative moderator coefficient.

If everything works ok, its likely that even when the generator fuel runs out, the remaining decay heat won't be enough to melt the reactor down but I wouldnt like to try it.


I know that beyond design basis studies have looked at the effects, but its not something that Operators generally look at in simulator exercised.

Edited by Gary C on Saturday 29th January 06:24

mike74

3,687 posts

139 months

Saturday 29th January 2022
quotequote all
I think a few nuclear power stations going bang would be a small price to pay for the overall gains the planet would benefit from by 99.9% of the human population disappearing over night... some minor short term pain for long term gain.

Roofless Toothless

6,122 posts

139 months

Saturday 29th January 2022
quotequote all
WarrenB said:
Impossible, but, what would happen if the internet was just 'turned off'? No emails, no google, just back to phone calls, letters and books.
Makes me wonder how I managed to survive until I was 45 years old.

Dr Jekyll

23,820 posts

268 months

Saturday 29th January 2022
quotequote all
mike74 said:
I think a few nuclear power stations going bang would be a small price to pay for the overall gains the planet would benefit from by 99.9% of the human population disappearing over night... some minor short term pain for long term gain.
How do you know what the planet prefers? Or is it just what you would prefer?

105.4

Original Poster:

4,214 posts

78 months

Saturday 29th January 2022
quotequote all
Gary C said:
So at some point the reactors would trip. Lots of reasons for that to happen from faults to blocking coolers.

Rods would go in and the automated cooling systems would cool the reactor down.

What happens next depends.

Lets say its the grid that takes it off (as stations trip, the grid would collapse with the same result) and then the stations would be on backup generation. Each station has a lot of fuel to run the backups, but their design mission time is about 24 hours and even thought they can last much longer, they also assume that some equipment is shutdown as the requirements for cooling reduce. With no people, all systems would continue to run using more fuel than anticipated.

Haven't worked it out (its written down somewhere), but eventually the backup generators would stop and the cooling systems would shutdown.

Now, a reactor thats been shutdown for, lets say 7 days, is still producing about 5-10MW of heat and will begin to warm up. Eventually in theory some reactors can go critical again if they warm up enough and that would mean a meltdown.

Big cores such as AGR's heat quite slowly but have a positive moderator coefficient whereas most water reactors have a much smaller core and thus heat up quicker but have a self regulating negative moderator coefficient.

If everything works ok, its likely that even when the generator fuel runs out, the remaining decay heat won't be enough to melt the reactor down but I wouldnt like to try it.


I know that beyond design basis studies have looked at the effects, but its not something that Operators generally look at in simulator exercised.

Edited by Gary C on Saturday 29th January 06:24
Gary, thank you very much for that smile

Just one more question if I may….

What is / are positive & negative moderator coefficients?

Roofless Toothless

6,122 posts

139 months

Saturday 29th January 2022
quotequote all
mike74 said:
I think a few nuclear power stations going bang would be a small price to pay for the overall gains the planet would benefit from by 99.9% of the human population disappearing over night... some minor short term pain for long term gain.
I am always puzzled by this point of view. It would follow that 99% of our greatest talents - artists, musicians, scientists, inventors, philosophers - would also be absent.

Possibly there is a critical mass of genius without which humanity as a species would not thrive. A tiny population would mean a very bleak future.