|
Olothreutes posted:He looks at the starting inventory, 20,000 kCi, and sees that the current inventory is now only 12,000 kCi. He's a money guy, not a nuclear guy, so he comes to the facility manager and very seriously asks him where the hell the other 8,000 kCi have gone. "How can you lose 8,000 of these things in just 4 years?" I'm not a scientist or a bean counter but I imagine sources of radiation are the kind of thing you do track kind of well to make sure they don't get stolen and used for bad purposes, so how exactly do you track this kind of thing on your inventory? I assume the half-life/rate of decay is just an "on average" kind of thing, but are there so many atoms that you actually see almost exactly the predicted rate of decay, or do things vary a bit? If I could get past the presumably tight controls on access to this stuff, could I shave a little bit off every now and then without anyone noticing? I suppose if I keep doing it, it's going to keep looking like it's decaying faster and faster than expected, so maybe I can only do it once per source? * This is all hypothetical and I really really don't want to be exposed to any radiation at all 
|
#
?
Nov 26, 2016 07:26
|
|
|
|
| # ? May 14, 2024 21:07 |
|
|
yeah, even with a radionuclide mass the size of a virus, the law of large numbers would have taken over long ago.
|
|
#
?
Nov 26, 2016 07:34
|
|
|
|
|
#
?
Nov 26, 2016 07:34
|
|
|
Three-Phase posted:Yeah doesn't ionizing radiation do weird things with crystal lattices, like messing up some of the bonds? I think it can make some materials harder but more brittle? The only time I ever had to wear a dosimetry badge, I saw some cool samples of artificially colored topaz at the RPI linac. The beam can create dislocations that affect the color of minerals. https://www.rpi.edu/dept/linac/public_html/Radiation_Applications.html They also do fun stuff that involves hitting a dense target with some kind of big cross-section with the beam, spalling off neutrons at a right angle that go down a tunnel/tube to a very well shielded test chamber in order to see what happens to various electronics/systems. They couldn't get into specifics, so I expect there were some national security implications. The main passage to the target chamber was protected by something like a 2 foot thick slab of concrete/steel. The power supply involves some really fat transformers loaded with PCBs, with little windows to check for water condensation. In general, it's a really neat facility. Also interesting was the 5x5x5 foot stack of very pure lead blocks sitting on one side of the beam chamber. Something like 0.99999% if I recall correctly. It was really fun, and if you can find yourself by Rochester, I'd suggest seeing if they'll give you a tour. Rochester also had a small reactor at a Kodak facility at one point, apparently. http://gizmodo.com/5909961/kodak-had-a-secret-weapons-grade-nuclear-reactor-hidden-in-a-basement Edit: Wasn't that also a problem with early fuel rod casings? Now the zirconia based stuff is just vulnerable to hydrogen infiltration or something like that, but I seem to recall reading about issues with refueling operations involving cracks or something. Effective-Disorder fucked around with this message at 08:24 on Nov 26, 2016 |
|
#
?
Nov 26, 2016 08:12
|
|
|
Buttcoin purse posted:I'm not a scientist or a bean counter but I imagine sources of radiation are the kind of thing you do track kind of well to make sure they don't get stolen and used for bad purposes, so how exactly do you track this kind of thing on your inventory? I assume the half-life/rate of decay is just an "on average" kind of thing, but are there so many atoms that you actually see almost exactly the predicted rate of decay, or do things vary a bit? If I could get past the presumably tight controls on access to this stuff, could I shave a little bit off every now and then without anyone noticing? I suppose if I keep doing it, it's going to keep looking like it's decaying faster and faster than expected, so maybe I can only do it once per source? Track the total mass.
|
|
#
?
Nov 26, 2016 08:55
|
|
Yes, it's like a lava lamp.
|
PittTheElder posted:Track the total mass. That doesn't work for alpha decay 
|
|
#
?
Nov 26, 2016 09:28
|
|
|
Effective-Disorder posted:The only time I ever had to wear a dosimetry badge, I saw some cool samples of artificially colored topaz at the RPI linac. The beam can create dislocations that affect the color of minerals. I once got to go along as a helper monkey on a trip to an accelerator in Ohio, a trip whose purpose was running acrylic slabs under an electron beam for the purpose of turning them into Lichtenberg Figures. There was an endless loop of plastic carts that ran under the beam, over and over. The acrylic slabs only took up a few carts here and there, and the others were open for experiments. So I repeated an experiment that I'd heard about -- I put some ordinary table salt in a ziploc bag, and left it on a cart, to go under the beam dozens of times. The salt turned brown. It still tastes like salt. I still have most of it in my freezer, still in the original baggie. It's still brown. But if you heat it up over a flame, it turns white again. I can't seem to find a video of that, but it happens. Anyway, yeah, I have tasted salt that's gone under a 5MeV electron beam a few dozen times. It's brown. It's kind of cool to know scientists who work on big heavy extreme government equipment.
|
|
#
?
Nov 26, 2016 09:54
|
|
|
Sagebrush posted:That doesn't work for alpha decay Strictly speaking it doesn't work at all. Once the atom decays and de-excites to ground level it weighs less. Not by any measurable* amount, but it does happen. *You can actually measure this amount, but it requires some really bizarre equipment with super high sensitivity. Buttcoin purse posted:I'm not a scientist or a bean counter but I imagine sources of radiation are the kind of thing you do track kind of well to make sure they don't get stolen and used for bad purposes, so how exactly do you track this kind of thing on your inventory? I assume the half-life/rate of decay is just an "on average" kind of thing, but are there so many atoms that you actually see almost exactly the predicted rate of decay, or do things vary a bit? If I could get past the presumably tight controls on access to this stuff, could I shave a little bit off every now and then without anyone noticing? I suppose if I keep doing it, it's going to keep looking like it's decaying faster and faster than expected, so maybe I can only do it once per source? We do actually keep really close tabs on this sort of thing. In part because in the past sometimes very small sources get dropped and roll under a cabinet, slipped into a notebook between some pages, or buried in random junk in a drawer. Then you have some unlucky schmuck who ends up combing the entire lab with a portable detector looking for the missing thing. People are much better about this now than they were 40 years ago. As to the stuff in the GIF, it's not quite the same as a small check source. These are massive ingots of cobalt 60 that they store in huge water tanks below ground. When you want to use them they open the access port from the test chamber to the holding chamber and then raise the source out of the pool to irradiate something. If you went close to the source to attempt to take anything you'd just die. The water is a good shield, but you need many feet of it to really work, so being close enough to shave something off would also mean being close enough that I suspect you would have less than a minute to contemplate just how big a mistake you made. As other people have covered, the law of large numbers takes over very rapidly even for sources measured in microcuries, let alone thousands of kilocuries. The behavior of the group as an average is very well characterized. Powered Descent posted:I once got to go along as a helper monkey on a trip to an accelerator in Ohio, a trip whose purpose was running acrylic slabs under an electron beam for the purpose of turning them into Lichtenberg Figures. We've done this in our research reactor on campus, but with neutron radiation. Salt will act as a sort of thermoluminescent dosimeter medium, where the radiation excites electrons in the material, inducing the color change, but the electrons become trapped and won't de-excite to ground state without an added push, like some heat. If you heat it in the dark it will actually emit light as the electrons return to ground state. Three-Phase posted:Yeah doesn't ionizing radiation do weird things with crystal lattices, like messing up some of the bonds? I think it can make some materials harder but more brittle? Radiation hardening and embrittlement is a real thing, and a real problem in some instances. Basically anything with a regular structure can be dislodged by incoming radiation with enough energy. So you end up with spaces that had an atom and don't anymore (vacancy) or places where an atom has come to rest between others in the lattice (interstitial) pushing everything around it to make room in the lattice where there was none. You can then create big chains, loops, lines, voids, all sorts of things based on these movements, and how materials behave under these conditions is a robust field of study right now. There is a strong desire for us to build structural materials that can last longer, because that's one of the limiting factors for reactor operators right now. When the assemblies come out after 4.5-6 years in a reactor environment they are beat to poo poo. We would like to be able to push them further and to run longer but we can't do that without knowing how the materials will behave. And being able to prove how they behave to the NRC beyond a shadow of a doubt, which requires a load of data. Olothreutes fucked around with this message at 11:24 on Nov 26, 2016 |
|
#
?
Nov 26, 2016 10:34
|
|
|
verbal enema posted:I looked through several pages anyone have the gif or whatever of the kid doing a flip out a cargo net and just disappearing into the abyss Was it posted in this thread, because then I can go through my post history. Edit: Nope, must have been posted in the Schadenfreude thread. Edit2: Yup. Mierenneuker fucked around with this message at 11:22 on Nov 26, 2016 |
|
#
?
Nov 26, 2016 11:16
|
|
|
Effective-Disorder posted:
That Gizmodo article is one of the shittiest articles I've ever read. It made me want to slap the writer.
|
|
#
?
Nov 26, 2016 14:24
|
|
|
Now I can't get the image out if my head of some lab tech thinking he's going to make a buck sneaking up to a 20,000 ci source to scrape a bit off and then just falling over dead before he gets close. Anyway, this wiki is always an interesting reads. A good mix of lovely situations, incompetence, and blatant stupidity. From the Goiânia accident: quote:The day before the sale to the second scrapyard, on September 24, Ivo, Devair's brother, successfully scraped some additional dust out of the source and took it to his house a short distance away. There he spread some of it on the concrete floor. His six-year-old daughter, Leide das Neves Ferreira, later ate a sandwich while sitting on this floor. She was also fascinated by the blue glow of the powder, applying it to her body and showing it off to her mother. Dust from the powder fell on the sandwich she was consuming; she eventually absorbed 1.0 GBq and received a total dose of 6.0 Gy, more than a fatal dose even with treatment. Don't feed the baby caesium-137.
|
|
#
?
Nov 26, 2016 15:28
|
|
|
Reminds me of the time my grade-school got in the news because kids had found multiple mason jars full of mercury hidden near a creek and played with it for hours before anyone knew what was up. Some had put it in their mouths to see if it would make their teeth silver.  I don't know if they ever found out who had put the mercury there or why. It was close to a hospital and a bunch of medical offices; I wonder if it could have been waste.
|
|
#
?
Nov 26, 2016 15:47
|
|
|
I don't understand how any human ever can break into a hospital, find something that glows, and assume that it obviously must be a special type of gunpowder.
|
|
#
?
Nov 26, 2016 15:50
|
|
|
Mierenneuker posted:Was it posted in this thread, because then I can go through my post history.
|
|
#
?
Nov 26, 2016 15:51
|
|
|
|
|
#
?
Nov 26, 2016 16:38
|
|
|
Doc Hawkins posted:Reminds me of the time my grade-school got in the news because kids had found multiple mason jars full of mercury hidden near a creek and played with it for hours before anyone knew what was up. Some had put it in their mouths to see if it would make their teeth silver. Mercury is fairly safe, as long as you don't inhale it in vapor form. You could probably drink a good amount of it and it's going to pass right through you without doing any damage. Not that I'd recommend it. I was going to ask if the incident you remembered was one I recalled from the news, but turns out "mercury found under house" is not quite the unique news story I thought it was. Found this though: http://www.newsweek.com/liquid-mercury-found-mexican-pyramid-could-hold-secrets-teotihuacan-325450
|
|
#
?
Nov 26, 2016 17:26
|
|
|
Rust Martialis posted:That Gizmodo article is one of the shittiest articles I've ever read. It made me want to slap the writer. Sorry about that. After re-reading it is fairly crap after all. Either way it wasn't a reactor, but a californium neutron flux multiplier. My bad.
|
|
#
?
Nov 26, 2016 18:07
|
|
|
I guess this might be interesting to someone. I work for an engineering firm that does mostly military flight controls, and we have to think about Single Event Upsets (SEUs) sometimes. That's when a bit in a memory device is interacted with by cosmic rays or alpha particles or whatever, causing the bit value to flip. It can happen on the ground, but when you're up in the air p high it becomes much more likely. It's also possible to have a bit permanently stuck (Single Event Latchup: SEL,) but I'm not as familiar with that. This is more likely to affect faster memories (I've only seen it in cache memories) where the voltages and the charge across the device are lower, therefore easier to disturb. I guess it would also be more likely to affect overclocked devices. You can "harden" the memory, but that either slows it down or means adding size to the device. The more common way to "fix" it would be Error Correcting Code (ECC) memory, which is able to detect and repair single bit errors in values when read. I know it's possible to send devices for radiation exposure testing, and I know we've done it before, but I've never been part of it. I guess that's probably what they're looking for mostly, though. I also imagine space work requires this as a standard. Real e: I mean they're looking for that when testing electronics, I'm sure radiation can affect things like seals and such having read everyone's responses.
|
|
#
?
Nov 26, 2016 18:09
|
|
|
Sirotan posted:Mercury is fairly safe, as long as you don't inhale it in vapor form. Qin dynasty court physician parachute account spotted.
|
|
#
?
Nov 26, 2016 18:17
|
|
|
JoelJoel posted:Qin dynasty court physician parachute account spotted. Yes but was he wearing a Hard Hat while operating his Time Machine?
|
|
#
?
Nov 26, 2016 19:15
|
|
|
So the mechanism of action and results of radiation embrittlement is the same as work hardening basically? I want an atomic shot peening rig.
|
|
#
?
Nov 26, 2016 19:32
|
|
|
DiHK posted:Yes but was he wearing a Hard Hat while operating his Time Machine? No time machine needed. He kept the real immortality pills and poisoned that dumb gently caress emperor.
|
|
#
?
Nov 26, 2016 19:33
|
|
|
Our money lost is more accurate.
|
|
#
?
Nov 26, 2016 20:16
|
|
|
Doc Hawkins posted:I don't know if they ever found out who had put the mercury there or why. It was close to a hospital and a bunch of medical offices; I wonder if it could have been waste. Was it in a gold area? It is/was used to collect and concentrate flower gold.
|
|
#
?
Nov 26, 2016 21:17
|
|
|
JoelJoel posted:No time machine needed. He kept the real immortality pills and poisoned that dumb gently caress emperor. Ahhhh, the ol' ancient oriental secret!
|
|
#
?
Nov 26, 2016 22:57
|
|
|
BattleMaster posted:I don't understand how any human ever can break into a hospital, find something that glows, and assume that it obviously must be a special type of gunpowder. Lack of education? You live in a Brazilian favela, you have a grade-school education at best, and you think of a hospital as a place where people go to get healthy, not a place full of dangerous poisons that will kill you before you even feel it. You have no concept of radiotherapy or gamma emitters or cobalt-60 or cerenkov radiation. The glowing blue powder is just glowing blue powder, and the closest analog you have for "powder with some kind of energy in it" is gunpowder, which is harmless unless you set it on fire. What's the big deal? Olothreutes posted:We do actually keep really close tabs on this sort of thing. In part because in the past sometimes very small sources get dropped and roll under a cabinet, slipped into a notebook between some pages, or buried in random junk in a drawer. Then you have some unlucky schmuck who ends up combing the entire lab with a portable detector looking for the missing thing. People are much better about this now than they were 40 years ago. I have an OSHA story about that. The house I grew up in had been previously owned by a physics professor at the local university. He died and left no children, leaving everything to the university, and my parents ended up buying the house in the sale of his estate. A few months after we moved in, when I was about 6 years old, some grad students and staff from the university came by with a geiger counter. I remember them walking around the house with my parents for an hour poking at various things, then eventually leaving, seemingly satisfied. Years later, my parents told me the story. Apparently the university had been cleaning out this professor's office (he had died fairly suddenly, of a stroke or something) and they had found a dozen or so different radioactive sources ranging from ore samples to actual refined test emitters sitting in his desk drawers and filing cabinets. Some labeled, some not, including one they described as "particularly strong" (not sure what it was, sorry) on a shelf that was six inches away from a drinking fountain on the other side of the wall. With no kids and a reputation as an absent-minded professor, they were understandably concerned that he might have taken some of his work home with him, and were terrified that they might have sold a radioactive house to a family with two young kids. Fortunately they didn't find anything of note and I grew up just fine. I grew up just fine. I grew up just fine. I grew up just fine Sagebrush fucked around with this message at 23:20 on Nov 26, 2016 |
|
#
?
Nov 26, 2016 23:14
|
|
|
Sagebrush posted:Fortunately they didn't find anything of note and I grew up just fine. I grew up just fine. I grew up just fine. I grew up just fine Don't worry, we can all guess how hard it must be to keep those three hands with 7-8 fingers each coordinated. fake-edit: Everything I know about long-term exposure to radiation comes from the meticulously researched documentary "The Simpsons".
|
|
#
?
Nov 26, 2016 23:31
|
|
|
Hollow Talk posted:fake-edit: Everything I know about long-term exposure to radiation comes from the meticulously researched documentary "The Simpsons". 
|
|
#
?
Nov 26, 2016 23:42
|
|
|
Phanatic posted:For historical reference, the Georgia Nuclear Aircraft Lab right outside Atlanta used a completely unshielded megawatt nuclear reactor to do that kind of thing back when they were thinking of making a nuclear-powered B-36. Reactor was on an elevator, normally kept in a pit in the ground, and you'd raise the elevator to irradiate your test samples and the surrounding area. They found that, among other things, it would turn the rubber in the tires brittle and hard and turn hydraulic fluid cloudy and thick. Among other things. The Georgia Nuclear Aircraft Laboratory was a cold war era facility that quote:was the site of Lockheed's lab for investigating the feasibility of nuclear aircraft. The site was used for irradiating military equipment, as well as the forest to determine the effect of nuclear war, and its effects on wildlife. The area was closed in 1971 and acquired by the city of Atlanta for a second airport, but its topography was determined to be ill-suited for an airport. Documents explaining what went on at the site remain highly classified, and the entrance to the underground portion of the facility has been buried. The only objects left above ground were the concrete foundations on which the buildings and reactors were placed. The heart of the GNAL was a 10MW unshielded reactor that was normally stored submerged in a cooling pond, but was hoisted up into the air to irradiate materials during experiments. Before construction, the intent had been to irradiate aircraft systems to see how well they held up to radiation with the end-goal of developing a nuclear-powered bomber that could remain in flight for weeks to months at a time. By the time the facility was finished, this had been all but dismissed as ridiculously impractical and the facility took on a new purpose: to study the effects of radiation levels that would be present in the aftermath of nuclear war. A typical test would consist of several steps: The material to be irradiated would be brought into the reactor building on rail cars. Next, everyone on site inside of the "lethal fence," the area in which humans could receive fatal doses of radiation (look for the circle in the woods on this map) would get into the underground safety bunkers. Once the site was clear, the reactor would be brought up to its operating power of 10 megawatts and hoisted out of the pit into the air for the duration of the test, then lowered back into the pit. Once the all-clear was sounded, the rail cars would be moved to an outdoor cool-down area (one of the fenced-off areas still off-limits to this day because of contamination) where they would sit for days or weeks until they were safe to bring into the hot cell and be manipulated, repaired, etc. by robotic tools because they were still too radioactive for people to get near them. Sometimes, early on, they tested aircraft parts. Other times, they tested various materials, including pine wood that was dubbed "Lockwood" (Lockheed was running the site) which became quite hard and durable, and was used in various applications including flooring at the IAEA headquarters. There were also "biological materials" tested, which is a nice way of saying they exposed live animals and the surrounding forest. Doses of radiation were measured in rads; Wikipedia sources say that a whole body dose of 400 rads will kill the average person, and off the top of my head I think 1000 will kill most animals. Several ten hour tests were conducted, with rodents and birds exposed to a mean whole-body dose of 6000-8000 rads and a peak measured dose of nearly 30,000. Nearby trees lost all of their foliage within a week of the first test. Then came the big one, a test to simulate the aftermath of a nuclear attack. The reactor was raised and left in the elevated position for a full three weeks. Trees 1000 feet from the reactor absorbed as much as 100,000 rads. Levels at the lethal fence perimeter 3000 feet away were between 500 and 1000 rads, enough to kill a person. The site was shut down in spring of 1971 and cleanup took just over a year. Most buildings were razed and only the concrete pads left behind, but there are a few still standing. The hot cell and several surrounding structures are still dangerously radioactive due to high levels of cobalt-60 and cesium-137 and won't be safe for demolition for another 30-50 years. The pump house building that supplied cooling water for the reactor is still standing, just a small concrete shack. Some explorers with a very poor sense of self-preservation have cut the double fence and entered the Hot Cell building with a Geiger counter confirming the official story that it's not safe to be there. Trees inside the hot cell area still show signs of radiation damage and mutations. The underground bunkers were gutted but left intact and the entrances buried. Every few years, the exploration bug bites someone and they dig it out. The lower levels are flooded, but there's apparently plenty to see.
|
|
#
?
Nov 26, 2016 23:42
|
|
|
That is very cool. What is the circle in the forest, exactly? Where was the reactor, and where are these contaminated rail yard areas and hot cells you're talking about? e: here's everything annotated, but the circle is still a mystery. If it's where the reactor used to be, why is the grass still mowed around it? What's the tree-covered area in the center? https://www.google.com/maps/d/u/0/viewer?msa=0&mid=1co9EDyiFusWYhzB5wmfQ6B8_Dvk&ll=34.36093617403195%2C-84.15849995095698&z=15
|
|
#
?
Nov 26, 2016 23:49
|
|
|
Jump to 3:54 if the link doesn't take you there https://www.youtube.com/watch?v=aqoHJD58M54&t=234s
|
|
#
?
Nov 27, 2016 01:43
|
|
|
`Nemesis posted:Jump to 3:54 if the link doesn't take you there Man, Sidorovich is gonna be thrilled when the rookies bring home the artifacts resulting from that hot mess.
|
|
#
?
Nov 27, 2016 01:48
|
|
|
|
|
#
?
Nov 27, 2016 02:07
|
|
|
quote:In four milliseconds, the heat generated by the resulting enormous power surge caused water surrounding the core to begin to explosively vaporize. The water vapor caused a pressure wave to strike the top of the reactor vessel, causing water and steam to spray from the top of the vessel. This extreme form of water hammer propelled control rods, shield plugs, and the entire reactor vessel upwards. A later investigation concluded that the 12,000-kilogram (26,000 lb) vessel had jumped 2.77 metres (9.1 ft) and the upper control rod drive mechanisms had struck the ceiling of the reactor building prior to settling back into its original location. The spray of water and steam knocked two operators onto the floor, killing one and severely injuring another. One of the shield plugs on top of the reactor vessel impaled the third man through his groin and exited his shoulder, pinning him to the ceiling. woof.
|
|
#
?
Nov 27, 2016 02:21
|
|
|
Look, it loving fits doesn't it.
|
|
#
?
Nov 27, 2016 02:27
|
|
|
JoelJoel posted:Anyway, this wiki is always an interesting reads. A good mix of lovely situations, incompetence, and blatant stupidity. Thanks, I think I've read and freaked out about all the nuclear accidents but I hadn't read this page before. I expect that I'll have a nightmare where I see the sign but I can't run  
|
|
#
?
Nov 27, 2016 04:07
|
|
|
That looks like a guy caught in a triangular room going for the spear so he can kill the menacing skull, while dodging arrows on bungee-cords being dropped from a ceiling fan.
|
|
#
?
Nov 27, 2016 05:03
|
|
|
flosofl posted:That looks like a guy caught in a triangular room going for the spear so he can kill the menacing skull, while dodging arrows on bungee-cords being dropped from a ceiling fan. the man is in a pyramid tomb and snakes are pouring out of a fan-shaped hole in the wall. he must grab the spear to defend himself, or he will end up like the previous intruder.
|
|
#
?
Nov 27, 2016 05:16
|
|
|
flosofl posted:That looks like a guy caught in a triangular room going for the spear so he can kill the menacing skull, while dodging arrows on bungee-cords being dropped from a ceiling fan. Must be treasure in there
|
|
#
?
Nov 27, 2016 05:26
|
|
|
|
| # ? May 14, 2024 21:07 |
|
|
Due to risk of static electricity, do not enter vehicle during fueling operations linked cause of  http://i.imgur.com/snGeDER.gif
|
|
#
?
Nov 27, 2016 05:32
|
|