The point is that they could potentially abscond with nuclear material before being surrounded, obviously.

Obviously. Good luck with that.

Handling nuclear material straight out of the reactor is a good way to kill yourself very painfully.

Sure, but if we're talking about terrorists that a documented history of being willing to blow themselves up, I don't see why they wouldn't do this too. To avoid the painful death, blow yourself up after absconding but before radiation poisoning really takes its toll.

Terrorists willing to blow themselves up at a time of their choosing is the key there. With nuclear waste hot enough to be a menace, the window between getting the material and being painfully incapacitated and/or dead by the material is pretty damn small. Especially since nuclear plants tend to have things like lots of checkpoints and security.

We're talking about people with EG civil engineering degrees masterminding these plots. The middle-eastern terrorists of yesteryear are not necessarily uneducated. Osama Bin Laden was educated as an engineer in the US and likely would have thought through the endgame and implications of such a plot well before executing it.

These people are not stupid and would likely know what they are getting in to. I'd be more worried about a single unhinged person, but that's why we have security guards, and the problem would likely solve itself in short order in that case.

If you receive around 1 Gy in five minutes, you won't abscond very far. And you would likely receive a lot more. Not to mention that you would leave a trail of radioactivity from the reactor to your lair/hiding place.

But it is well possible that some people could still try. The Four Lions, only in the real world.

I’ve personally seen someone get 7 Gy and be relatively functional (in a localized area) - no worse than he went into the OR anyway, to get the stent put in his brain. And he almost certainly lived another decade or so.

The other stuff sure, but it takes a truly mind boggling amount of radiation to incapacitate someone (near) instantly. A lot more than that.

100-150 Gy? The only concrete number I found looking around for ‘instant’ was 1000 Gy to likely kill someone within an hour.

Localized exposure is a different story, some body parts can take a lot of radiation. IDK if someone, having just burglarized a live reactor, can keep their exposure localized in a favorable place.

I think incapacitation is what matters. The human body will fight death for some time, but it won't be able to running around with a heavy backpack of fission material. Various tissues will scream bloody hell almost immediately from being torn apart by the radiation.

True, though notably the Chernobyl 'firefighters' were picking up hot chunks of core and fuel from the reactor building roof, and reported at most feeling tired at the time. They did die shortly afterwards, but that was weeks to a month after.

Definitely a death sentence either way.

Here's an IAEA report from an incident where a worker walked into an irradiation room of a commercial irradiator with the radioactive source still up - he was only there for about one minute and received a dose of "only" about 10-20Gy total, but realized something was wrong because of intense pain that developed shortly after entering the room, followed by intense neusea and diarrhea 5 minutes later. Despite receiving urgent care immediately he still died a month later.

It's a fascinating(if very morbid) read if you want to have a look:

https://www-pub.iaea.org/MTCD/publications/PDF/Pub925_web.pd...

The point is, that maybe the terrorists wouldn't be inacapacitated, but they certainly wouldn't be able to ignore the effects for very long if at all.

Would it even be painful? Wouldn't the stuff from the reactor just kill you promptly?

IDK how many real-world casuistics we actually have, but Wikipedia says that absorbed dose over 30 Gy results in severe headache, severe fever, nausea, vomiting and seizures, with death taking up to two days.

I linked it in another comment, but I'll put it here as well - here's an IAEA report about an accident where a worker walked into an active irradiation room of a commercial irradiator, he was there only for about a minute total but had to leave because of intense pain which made him realize something is wrong. The total dose is estimated at 10-20Gy but it was still enough to make him very unwell almost immediately and caused death about a month later:

https://www-pub.iaea.org/MTCD/publications/PDF/Pub925_web.pd...

Yeah, we are pretty lacking on high end data but my understanding was somewhere around 50Gy was expected to knock out brain function. And picking up the hot stuff from a reactor is way above that.

Terrorists don't need to take over, they just need to plant a big enough bomb or hit it with a big enough plane that it causes a radioactive disaster. Not only do they not necessarily care about their survival, they might actively crave death.

  > In the United States, the design and thickness of the containment and the missile shield are governed by federal regulations (10 CFR 50.55a), and must be strong enough to withstand the impact of a fully loaded passenger airliner without rupture.

[1] https://en.wikipedia.org/wiki/Containment_building

Will this apply to SMRs?

Very likely. In the US, all civilian nuclear applications are under the oversight of the NRC, and the NRC is a very conservative organization. I don't see them relaxing such any regulation for SMR's, let alone a regulation with such 9/11 vibes.

Your assumption is that they want to get away.

What if they just want to overide the safety mechanisms of the reactor and trigger a meltdown?

This is why the crackdown on modern terrorism became so draconion.

They love death as we love life.

Well, this actually happened. A guy with a death wish decided to commit suicide by blowing up a nuclear reactor, and he succeeded [1].

Well, actually we don't know this for sure, because the guy (obviously) did not survive to tell the story. It may have been intentional suicide, or simply an unintentional operator error.

But it does not matter. Since then the design of nuclear reactors evolved in such a way as to make it very difficult for an operator to be able to intentionally or unintentionally trigger a blow-up or a melt-down.

[1] https://en.wikipedia.org/wiki/SL-1

Thanks for the informative reply.

It’s good to hear that it’s risk that is already mitigated.

Personally the thing that turns me off nuclear the most is that if things do go wrong sections of land basically become uninhabitable for thousands of years. I probably shouldn’t care but it seams like a major downside.