Thread by @TomMostlyZen

There is clearly a lot of fear about the #Zaporizhzya Nuclear Power Plant at present. The Russians are making threats, but how seriously should we take them?

What are the real likelihood AND severity of of these threats?

A thread 🧵/1
#ZaporozhyeNuclearPowerPlant

I work as a Clinical Psychologist and have a background in Physics. Last night, I discussed the possible Russian threats to the ZPP with nuclear experts Mark Nelson @energybants and Eugene Shwageraus @shwageraus on the #MriyaReport Twitter Space @MriyaReport /2

When scared about the chances of something terrible happening, we need to ask ourselves:

1) What specifically do I think might happen?
2) How likely is this to happen?
3) How bad would it be if it actually happened?

With nuclear power, we really need to ask & trust experts /3

Specifically, what might happen at #ZaporozhyeNuclearPowerPlant ?

In psychology, the best predictor of future behaviour is past behaviour.

What did the Russians do when they occupied Chernobyl & then retreated? They took the staff & guards prisoner. They didn’t bomb it /4

What did the Russians do when they fled from #Irpin and #Bucha ? They killed innocent civilians.

I think it’s 80% likely the Russians will take the Nuclear scientists & engineers prisoner when they go. There’s also a non-zero change that they murder them, but far less likely
/5

Neither of these are a nuclear disaster, but are horrific and quite possible.

People aren’t worried about that though, they’re worried about radiation being released. How might that happen?

/6

The easiest way for the Russians to release radioactive isotopes from #Zaporizhzya NPP would be to stop coolant water from circulating in the spent fuel rod coolant pools. I will try to massively simplify this

/7

Spent nuclear fuel rods are still hot as the isotopes decay over time. They are encased and kept cool in cooling ponds full of water. If the water isn’t continually flowing and replaced, it gets hot and evaporates

/8

If the Russians cut off the water supply to cool the spent fuel rods, they could overheat, and the cladding could get damaged. This would release radioactive isotopes for a few kilometres.

*But nothing like as bad as Chernobyl or Fukushima*

/9

Damaged fuel rods, even melting or oxidising cladding, are not a reactor explosion, meltdown, or fire (like #Chernobyl) or a hydrogen explosion (like #fukushima)

It’d be bad for #ZaporozhyeNuclearPowerPlant but people in Southern Ukraine would be OK.

/10

How likely are the Russians to do this? At first I thought extremely unlikely, but then I remembered Saddam Hussein’s army setting fire to Kuwaiti oil wells after they fled in the first Gulf War, and I thought, perhaps a 10% chance?

/11

Mark and Eugene on #MriyaReport gave me more information. Mark said that Russia needs the ZNPP for electricity in Crimea. Without it, they’ll have blackouts. This makes it less likely.

/12

Eugene pointed out to me that people who would know how to damage the fuel rods wouldn’t be crazy enough to do it, and people who would be crazy enough to do it probably wouldn’t know how.

I now think the chance of fuel rod damage and contamination is about 2% likely

/13

“But what if the Russians blow up the #Zaporizhzya nuclear reactor Tom?!?”

Eugene explained that the Russians could cause the fuel rods *inside* the reactor to melt, or possibly burn, but this *wouldn’t* cause the reactor to explode as happened at Chernobyl.

It wouldn’t

/14

This is much harder to do than damaging spent fuel rods. The #Zaporizhzya reactor is encased in a massive amount of concrete. Regular bombs or tank shells can’t easily penetrate it.

Crazy people might do it but don’t know how. People who know how aren’t that crazy.

/15

I give it about a 0.1% probability that the Russians drill deep into the concrete of the #ZaporizhzhiaNPP and use enough dynamite or plastic explosive to split the reactor open.

Would YOU want to be the guy who did that drilling or set the explosives? It would be suicidal

/16

Cracking open the nuclear reactor at #ZaporozhyeNPP would still not be a reactor explosion and fire as bad as Chernobyl was. It’d be really bad for anyone nearby though. Then again, that’s true of anywhere the Russians Bomb in this war

/17

Just to complete the thread, people have asked what would happen if the Russians used a tactical Nuclear Weapon to bomb the #ZaporizhzhiaNPP ?

That would likely spread radiation a lot further, but it would also most likely cause WW3.

The Russians won’t do this

/18

So:

80% chance the Russians take #ZaporizhzhiaNPP staff prisoner

10% chance (maybe) that they kill them 😔

2% chance they damage spent fuel rods, spreading small amount of isotopes locally

0.1% chance the wreck but don’t break open the reactor

/19

0.1% chance that a crazy and suicidal Russian drills into the #Zaporizhzhya nuclear reactor, plants explosives and cracks open. This still wouldn’t be as bad as Chernobyl

Effectively 0% chance that they drop a nuclear bomb on top of it

/20

Maps like this are simply not true (sorry Pedro). Even Chernobyl didn’t kill everyone in a radius that large. Even the largest nuclear bomb ever made (Tsar Bomba, Google it) wouldn’t kill everyone in that radius

/21

“What about radiation spreading in that radius Tom? Won’t people die slowly of cancer?”

Not at that radius. Even Chernobyl didn’t make everyone in Ukraine and nearby countries die of cancer, and it’s been 30+ years now.

Please try not to worry too much guys 🙏

/22 END

UPDATE: The NPP was cut off from supplying Crimea with electricity in 2015, so my tweet above about Crimean electricity is incorrect.

But it still supplies vast areas of Russian held Southern Ukraine with electricity, so if the Russians damaged it they’d have blackouts

/23

UPDATE: Here’s another Nuclear expert talking to the @BBCNews and saying the same thing as Mark and Eugene said to me for my thread. The most risky thing is the spent fuel rods melting, and that’s nothing like as dangerous as Chernobyl

/24

bbc.co.uk/news/world-eur…