just1monkey t1_ir6yckb wrote
Reply to comment by chickenofthesquee in Many scientists see fusion as the future of energy – and they're betting big. by filosoful
But these plants would presumably be on and going, right, protected by whatever we have in place to keep it from wreaking havoc on our global backyard?
So an ill-intentioned person could focus on attacking and taking down those safeguards, in order to trigger the adverse consequences they’re there to prevent.
I may not be following you on this weaponization point though, because it seems almost like you’re saying that fusion both is (or has been) and isn’t weaponizable?
Are you saying fusion reactors are just much harder to sabotage? Or impossible?
EDIT: I’m pretty sure some of you are trying to double up nation-based (non-global) defense strategies with energy strategies for the savings. But the first needs to be a thing of the past really soon. REALLY SOON.
n_choose_k t1_ir7g4dg wrote
Impossible to sabotage. As soon as the containment field is compromised the reaction fizzles out.
just1monkey t1_ir7gqge wrote
So basically the only possible states are:
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On and safely contained; or
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Off and incapable of harm?
That almost sounds too good to be true, but pretty exciting if it is! I think I’d need to understand it better - the last time I remember reading about it is some old article that disappointingly concluded that cold fusion was impossible.
n_choose_k t1_ir7h0wy wrote
Oh, there might be some risks from contaminated materials that need to be contained, but it's not going to make a big boom and spread fallout. Also, this is hot fusion. Cold fusion is still doubtful...
just1monkey t1_ir7hcm4 wrote
Haha yeah I was just reading the article and seeing the extensive security measures, including the giant concrete barriers that are intended to stop like neutrons from flying everywhere and destroying us all.
Also seems like still at energy loss in the process, and I’d be leery of any energy efficiency that could be gained by sacrificing safety measures.
Oh well. :(
dewafelbakkers t1_iraflov wrote
>stop like neutrons from flying everywhere and destroying us all.
What the hell are you talking about
just1monkey t1_irailbb wrote
The relevant links are probably scattershot throughout the comments to the post, but here’s the most recent research paper that I’d found talking about it.
Here’s another article, somewhat older and using more impassioned(-ish) language, though easier to follow for folks like me.
dewafelbakkers t1_irampwc wrote
Your language sounds like you think one fusion reactor without shielding will result in neutron escaping and killing everyone is some kind of apocalyptic scenario. Neutrons do not work like that lol
just1monkey t1_irapr3v wrote
Ha, no, I also mentioned elsewhere that I really like the ITER shutoff design that allows for multiple different circuit-breakers to basically turn the whole thing off for any number of more dangerous scenarios.
What I’m mostly worried about, for immobile energy sources that can be “weaponized” (used broadly to mean being harm to others), is:
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The ability for a small group of coordinated bad actors with the right knowledge to weaponize it, in this case presumably by somehow keeping the reaction and tritium replenishment (or equivalent) going despite the mechanisms in place to prevent that. I consider this a more likely scenario than people might realize, because my view is that the tech to “hack” any defensive tech structure exists simultaneously with the creation of that defensive tech structure, effectively converting all of those scenarios into like these condottieri-style waiting games with only one ultimate absorption point: the defender slips up and fails to maintain all the necessary resources to defend against hacking attackers. I do think that an inside job is more likely to succeed for sabotage.
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The fact that this neutron radiation is deadly to humans, and also eats away at the very structures that are designed to keep it safely isolated. That’s like putting deadly acid in a jar and hoping that you’re still going to be around later to replace it. And what weirds me out is that all the formal safety/risk papers don’t even mention the fact that the neutron radiation from the fusion reaction itself can be weaponized, instead focusing only on like uranium production or whatever to make bombs (in what they categorize as like three different ways, that sound to me like Sneaky Mode 1, Sneaky Mode 2, Grunt Rush).
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If there’s even a possibility that it can be weaponized, then people need to consider strategic defensive and war-related crap, too. And I’m going to guess that’s going to mean a lot of annoying-as-fuck games of chicken and wasteful positioning. Also, my guess is that it’s going to be rare that “best for us in terms of energy infrastructure” is going to perfectly line up with “best for us if we’re fighting,” which means that whatever we do won’t be optimal, and at worst, we’ll just be missing two birds with one stone.
Haha, and yeah, I did hit the high hyperbole note with the “doom for all” rhetoric - you’re right about that and I don’t have any good excuses for that bit!
realbrownsugar t1_ir8ok7j wrote
Both fission and fusion are both “nuclear” reactions… but that’s where the commonalities end.
In fission, a radioactive isotope (such as uranium or plutonium) is constantly shedding particles and melting down. And the reactor uses graphite rods and heavy water cooling to moderate and manage how much of a chain reaction can take place. Without the rods and water, you could have a runaway chain reaction which could lead to reactor core meltdown… and if there’s more than critical mass of nuclear fuel… an A-bomb explosion to go with the meltdown. (Edit: As u/dewafelbakkers pointed out, this isn't really a concern as reactors don't use anywhere close to the critical mass required for an atomic explosion, nor do they do they enrich the fuel enough to reach such a critical point.)
Not to mention, radioactive decay of spent fuel and remaining uranium/plutonium goes on for aeons.
In Fusion, there is no natural radioactive decay. The natural state doesn’t lead to a meltdown, and there’s not really a need to actively moderate the reactor. In fusion, a lot of energy is needed to get the reaction going as well as to sustain and confine it. If the Torus breaks down for some reason, the magnetic confinement will fail, and plasma pressure will drop and the reaction will stop. And you are left with hydrogen/deuterium gas or heavy water.
It takes a lot of energy to get atoms to collide. Even in an H-bomb, the reaction trigger is provided by an A-bomb. So the energy from the first fission explosion collides the hydrogen atoms together to release the much larger output of the fusion reaction. And, in the fusion reactors, most of the energy spent is trying to get the hydrogen atoms in a hot plasma to collide inside a confined magnetic donut. If the magnets fail, the plasma disappears… sure it might do some damage due to hot gas, but that’s about it.
dewafelbakkers t1_iraloy9 wrote
>In fission, a radioactive isotope (such as uranium or plutonium) is constantly shedding particles and melting down. And the reactor uses graphite rods and heavy water cooling to moderate and manage how much of a chain reaction can take place. Without the rods and water, you could have a runaway chain reaction which could lead to reactor core meltdown… and if there’s more than critical mass of nuclear fuel… an A-bomb explosion to go with the meltdown.
Formerly in the industry. Most of this is a pretty OK explanation, but that last bit is very wrong and I fear you've been* exposed to some disinformation or are repeating misinformation. You may want to read up on the definition and usage of 'critical mass', but more importantly, there are no fission plants that could accidently result in a nuclear explosion. nuclear accidents can result in meltdown, as you stated correctly, and there are - in extreme and sometime unprecedented circumstances - risks of gas explosions or explosive pressure events... But not nuclear explosions or spontaneous nuclear bombs made from reactor cores. That exists purely in the realm of propaganda and cinema
realbrownsugar t1_iraoxwd wrote
Ah, thanks for pointing that out! I stand corrected. I was thinking about what happened at Chernobyl with the explosion, and yes… at worst, it could be considered a dirty bomb. There was an explosion, and enough fissile material ejected to be considered radioactive fallout, but it wasn’t an A-bomb. It was a steam explosion from all the coolant overheating.
dewafelbakkers t1_irb1whx wrote
Yes. Also remember that chernobyl had no proper containment in place, so even a steam explosion and meltdown today wouldn't result in an event like that.
just1monkey t1_ir8pziy wrote
Thanks! I did like the remote ancillary support structures design of ITER, which means that anyone with bad intentions would need to figure out how to keep the reaction going and keep the tritium flowing in particular. The latter part seems very hard to surmount, but I’d guess that tech improvements that actually let us run fusion with energy gain would also help with “hacks” to both of these for bad actors.
What are your thoughts on this article, written by someone who worked for decades on the Princeton fusion project, which notes in particular the danger of neutron radiation (which seems to erode the very structures intended to keep it contained and protected over time)?
EDIT: Found this!, wherein we are testing out how bad neutron radiation can fuck shit up! Damn!
Also, I admitted at some point that it’s been years since I looked at any of this stuff, and will admit now that I’m about two levels below layman on the topic. Also, I absolutely do not mean to offend anyone or make anyone feel bad (at least not too much if I can help it), but my suspiciousness hackles really get raised when people shut down what seem to be reasonable questions with fanatic fervor. That type of reaction always makes me suspect that there’s some sort of bullshit shield being put up.
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