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Ok so it's a failure mode that reactors are designed to absorb and super-criticality doesn't necessarily mean you explode, just that you maybe hosed up your fuel/reactor chamber.
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Mar 10, 2021 19:32
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CommieGIR posted:Yes, but usually in films they refer to it "going critical" which would mean its operating at a stable state when really they mean, usually that its going supercritical and running away in an excursion event. Right, so what I was trying to say is: "Criticality" is used to describe a thing that happens during fission. It does have a specific meaning: steady state fission reaction. This happens all the time on purpose in reactors. Most people have zero experience or knowledge of how a reactor works, beyond "radioactive stuff make power". This includes screenwriters. Criticality also occurs in fission accidents outside reactors. e: And the term "criticality" is used even when the particular accident features supercriticality for a short period of time. Fission accidents are scary, and they're probably most people's exposure to the word when it makes the news. This also includes screenwriters. Thus, I can understand how "critical" became Hollywood shorthand for "bad atomic poo poo is occurring and we might be irradiated", even when it has a proper technical meaning. I don't like it, but I can understand it. Phy fucked around with this message at 19:45 on Mar 10, 2021 |
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Mar 10, 2021 19:37
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Phy posted:Right, so what I was trying to say is: "Criticality" is used to describe a thing that happens during fission. It does have a specific meaning: steady state fission reaction. This happens all the time on purpose in reactors. Most people have zero experience or knowledge of how a reactor works, beyond "radioactive stuff make power". This includes screenwriters. Criticality also occurs in fission accidents outside reactors. e: And the term "criticality" is used even when the particular accident features supercriticality for a short period of time. Fission accidents are scary, and they're probably most people's exposure to the word when it makes the news. This also includes screenwriters. Thus, I can understand how "critical" became Hollywood shorthand for "bad atomic poo poo is occurring and we might be irradiated", even when it has a proper technical meaning. I don't like it, but I can understand it. Alrighty then  Just doing my part to correct that misconception.
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Mar 10, 2021 19:51
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this is one of those things when you're listening to a layman use terminology that's common yet strictly incorrect, and you just nod along with it because you know what they mean
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Mar 10, 2021 19:52
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Phy posted:Ok, but am I correct that if "critical" means "a self-sustaining fission reaction where the number of neutrons pinging about the fissile material is neither increasing nor decreasing", you still don't want to be standing next to it if it's unshielded and uncontrolled? That's the thing: "critical" means a steady-state, which implies that it's controlled. In films it's used to mean "oh poo poo," but in the real-world it means the opposite of "oh poo poo." Samuel L. Hacksaw posted:Ok so it's a failure mode that reactors are designed to absorb and super-criticality doesn't necessarily mean you explode, just that you maybe hosed up your fuel/reactor chamber. "Critical" is not a failure mode. "Supercritical" just means that you're in a state where power is increasing; that is also not a failure mode. "Prompt supercritical" can be a failure mode in a nuclear reactor(*), and is a necessary operating mode in a nuclear bomb. (*) - as a blanket statement, this'd be incorrect. There are reactors like TRIGA where you can pull the control rods entirely, the core'll go prompt supercritical, and the thermal expansion of the fuel elements will instantly stop the reaction, no harm done. But generally it's a bad thing in a reactor.
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Mar 10, 2021 19:52
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Phanatic posted:That's the thing: "critical" means a steady-state, which implies that it's controlled. In films it's used to mean "oh poo poo," but in the real-world it means the opposite of "oh poo poo." Sick! Thanks! I like how elegant nuke control is. I guess I was strictly talking about prompt supercritical but didn't appreciate the difference in the technical terms.
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Mar 10, 2021 19:57
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Phanatic posted:There are reactors like TRIGA where you can pull the control rods entirely, the core'll go prompt supercritical, and the thermal expansion of the fuel elements will instantly stop the reaction This is what happened with the Demon Core. Slotin shoved it aside, but the reaction had already gone subcritical due to heating.
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Mar 10, 2021 19:58
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I still can't get over how dumb he and his partners were, but maybe that's because I never handle fissile material. For all I know that core slowly whispered sweet nothings to Louis until he trusted it to not be an insanely dangerous object. Too trusting Louis, you always had been a fool.
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Mar 10, 2021 20:03
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By popular demand posted:I still can't get over how dumb he and his partners were, but maybe that's because I never handle fissile material. It doesn't help when you specifically carry out an experiment that Fermi told you would likely result in your death if you kept doing it that way.
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Mar 10, 2021 20:09
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Phanatic posted:That's the thing: "critical" means a steady-state, which implies that it's controlled. In films it's used to mean "oh poo poo," but in the real-world it means the opposite of "oh poo poo." Achieving criticality outside of a reactor, perhaps on the table right next to you, is absolutely "oh poo poo"
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Mar 10, 2021 20:09
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CommieGIR posted:It doesn't help when you specifically carry out an experiment that Fermi told you would likely result in your death if you kept doing it that way. Also that it had already killed Daghlian.
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Mar 10, 2021 20:11
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Slanderer posted:Achieving criticality outside of a reactor, perhaps on the table right next to you, is absolutely "oh poo poo" I mean, the entire point of the (poorly designed) experiment was to basically do just that: Come close to supercriticality but not enough to actually start a reaction. That was the entire reason it was such a bad idea. Platystemon posted:Also that it had already killed Daghlian. Hindsight is 20/20 but only if people actually listen, right?
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Mar 10, 2021 20:12
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CommieGIR posted:Alrighty then Oh yeah of course, I just wanted to make sure I was communicating my point clearly, sorry
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Mar 10, 2021 20:23
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By popular demand posted:I still can't get over how dumb he and his partners were, but maybe that's because I never handle fissile material. That's how it goes when you get too comfortable with something dangerous.
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Mar 10, 2021 21:06
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By popular demand posted:I still can't get over how dumb he and his partners were, but maybe that's because I never handle fissile material.
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Mar 10, 2021 21:16
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Cojawfee posted:That's how it goes when you get too comfortable with something dangerous. see: powered woodworking equipment
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Mar 10, 2021 21:36
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Didn't we have a nuclear/radiation thread on GBS a year or two ago? I love these kinds of discussions despite the fact I still do not understand anything about radiation. The most intriguing point I just read about acute radiation sickness is how there are immediate health effects upon exposure to events such as demon core. Immediate nausea, vomiting, diarrhea and headaches. Wild what is happening to your body in that split second.
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Mar 10, 2021 23:04
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The Real Amethyst posted:Didn't we have a nuclear/radiation thread on GBS a year or two ago? We do have the reactor thread: https://forums.somethingawful.com/showthread.php?threadid=3916500
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Mar 10, 2021 23:22
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CommieGIR posted:Its worth noting Prompt Criticality can happen in Reactors (as it did in SL-1) but its neither desired nor encouraged. Pulse operation in a TRIGA or similar reactor is intentional prompt criticality, no? https://www.youtube.com/watch?v=74NAzzy9d_4 though it's almost immediately arrested by the reactor's design so things don't go kablooey The Real Amethyst posted:Didn't we have a nuclear/radiation thread on GBS a year or two ago? The immediate vomiting is probably not directly a radiation effect but more your body going "holy gently caress something unexplainable but really bad just happened everywhere at once, I might be poisoned, get rid of food" as it does in a variety of situations. The really creepy part to me is that unless the radiation is so powerful it actually burns you to death, there aren't many acute symptoms of a lethal exposure. In fact for a few days to weeks after the incident you feel just fine. Except the radiation has killed all of your fast-dividing cells, such as those in your GI tract and bones and blood, so once the cells that are currently alive in your body start dying naturally with no replacements forthcoming, you just sort of...liquefy. grim Sagebrush fucked around with this message at 23:36 on Mar 10, 2021 |
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Mar 10, 2021 23:29
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https://i.imgur.com/YfNScyv.mp4
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Mar 11, 2021 00:21
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The Real Amethyst posted:Didn't we have a nuclear/radiation thread on GBS a year or two ago? There's my Nuclear thread in the Science forum! https://forums.somethingawful.com/showthread.php?threadid=3916500 Sagebrush posted:Pulse operation in a TRIGA or similar reactor is intentional prompt criticality, no? True, and its one of the few reactors capable of doing that without major damage, it also helps when you are not required to operate the reactor to generate power which means it can be kept cooler and deeper in water.
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Mar 11, 2021 00:28
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https://va.media.tumblr.com/tumblr_qprunoAmIJ1r0uzl6.mp4
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Mar 11, 2021 00:29
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Is this Valheim?
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Mar 11, 2021 00:32
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Atomic accidents, making of the atomic bomb, midnight in chernobyl, and command and control are some good books that'll learn you a lot about the subject. The plutonium processing plant fire in co is covered in atomic accidents and, just, holy poo poo. Also the prompt critical experiments in idaho where they just blew up reactors out in the open air. https://www.youtube.com/watch?v=mBb2oga4RWE jamal fucked around with this message at 00:42 on Mar 11, 2021 |
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Mar 11, 2021 00:34
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A fun nuclear bomb fact: In the first nanoseconds of a nuclear bomb, some plutonium atoms simply get flung out of the core at about 1% of the speed of light. Fast neutrons from the core sometimes catch up with these speeding plutonium nuclei and split them. It's not a significant part of the total energy released, but with the sheer number of nuclei splitting, some really improbable things happen. Hydrogen bombs work by using a nuke to set off hydrogen fusion, which releases fast neutrons so energetic that they can split uranium-238, and the whole assembly is surrounded with tonnes of uranium-238. Neutron bombs are simply a fusion bomb without the uranium shell, to produce a massive dose of fast neutron radiation.
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Mar 11, 2021 00:41
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I highly recommend LANL's "A Review Of Criticality Accidents" which covers a lot of ground. Most of it is from Russia, a couple in Japan, and a bunch at US facilities. Going back to the picture Plutonium rods being placed too closely to one another - there was an accident with a Plutonium solution at LANL in 1958 that blasted a worker with an estimated 13,000 REM. Too much solution was put into a tank and when the worker peeked through a porthole-style window in the tank and started the stirrer, it flashed blue. Ooops.
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Mar 11, 2021 00:42
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TotalLossBrain posted:Going back to the picture Plutonium rods being placed too closely to one another - there was an accident with a Plutonium solution at LANL in 1958 that blasted a worker with an estimated 13,000 REM. Too much solution was put into a tank and when the worker peeked through a porthole-style window in the tank and started the stirrer, it flashed blue. Ooops. The Forbidden Blue.
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Mar 11, 2021 00:51
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he got real close to nailing his foot to the roof a few times ... which might actually put him in a safer position, really
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Mar 11, 2021 00:59
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Those look like semi truck tires and they weigh about 100lbs apiece. Dude had a poo poo day for sure.
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Mar 11, 2021 01:00
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TotalLossBrain posted:
Note that they never figured out *why* there was so much plutonium in that tank.
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Mar 11, 2021 01:00
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Narrated by Winnie The Pooh.
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Mar 11, 2021 01:01
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ugh, you know some rear end in a top hat manager looking at this going "jeeze why don't they all work that hard," knowing full well they don't provide insurance.
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Mar 11, 2021 01:01
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CRUSTY MINGE posted:Those look like semi truck tires and they weigh about 100lbs apiece. Dude had a poo poo day for sure. I'm definitely glad they showed him moving after he took the hit.
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Mar 11, 2021 01:03
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CRUSTY MINGE posted:Those look like semi truck tires and they weigh about 100lbs apiece. Dude had a poo poo day for sure. I have no idea what he was trying to do. His poo poo eating grin makes me think he was just being an rear end in a top hat and planned to make someone restack his mess before the back stack gave him some instant karma.
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Mar 11, 2021 01:07
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Probably just needed tires to fill an order. You don't pick those tires up unless you have to, swinging them to the top of the pile is the really backbreaking part, but that's how you take more than one, just knock them over.ultrafilter posted:I'm definitely glad they showed him moving after he took the hit. Me too. About 20 years ago I worked in truck stops, changing tires, doing services, taking deep breaths of diesel exhaust and burnt gear oil. Tire tower missed me by a foot or so once, but my luck was bound for the bottom of a service pit. Stepped over a pit one night, foot slipped on the rail and I ate metal grate in the bottom of it, hosed up my knee temporarily, then got fired for it because safety. Two weeks later another truck stop owned by the same company hired me. It was way more redneck a shop and a lot more fun.
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Mar 11, 2021 01:11
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"Why's his safety line anchored below him?" *realizes it's an air hose* 
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Mar 11, 2021 01:14
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It looks like it's all roof to the ground like an A-frame, he can just slide down. Camera goes level-ish towards the end. Better be a mattress or something down there though.
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Mar 11, 2021 01:22
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Sagebrush posted:Pulse operation in a TRIGA or similar reactor is intentional prompt criticality, no? IIRC a higher dose can cause less short-term symptoms because the cells are dead dead dead rather than critically damaged and freaking out.
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Mar 11, 2021 01:30
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CRUSTY MINGE posted:It looks like it's all roof to the ground like an A-frame, he can just slide down. Camera goes level-ish towards the end. "Sliding" shirtless down a couple stories of oriented strand board doesn't sound much better tbh
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Mar 11, 2021 01:55
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CRUSTY MINGE posted:Those look like semi truck tires and they weigh about 100lbs apiece. Dude had a poo poo day for sure. gently caress that tubby kid.
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Mar 11, 2021 02:14
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