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Cosmic Rays To Reveal the Melted Nuclear Fuel In Fukushima's Reactors
the_newsbeagle writes: Muons, produced when cosmic rays collide with molecules in the atmosphere, are streaming through your body as you read this. The particles pass through most matter unimpeded, however they can interact with heavy elements like uranium and plutonium. That's why engineers at Japan's Fukushima Daiichi power plant are using muon detectors to look for the melted nuclear fuel inside the plant's three melted-down reactors. By determining where muons are being diverted from their paths, the detectors create images of the blobs of fuel. That's necessary because nobody knows exactly where the radioactive gloop ended up during the meltdowns.
Gloop is an element. TFS didn't say exactly which isotopic form of Gl they are looking for.
Have gnu, will travel.
Muon shadowgraphs of the Moon, a signature of the Moon's cosmic ray shadow on the upper atmosphere, are a common way of testing neutrino detectors buried under a km or more of rock. (Muons from the atmosphere tend to be the major source of confusion for such detectors; that's why they frequently do best looking down, as muons can't go through 12,000 km of rock.)
Oh, and archeologists have used muons to look through the Great Pyramid.
We've been using muon detectors for over 40 years to detect nuclear-related activities in various countries, including reactor installation, stockpiling, bomb-building, and so on. One of the reasons for the ability to move MX missiles around underground was so that long term muon detector observation by the Soviets could not pinpoint the location of the missiles.
I wonder if we can get some good images of the elephant feet that are all over that building...
Yes it's an anecdote! Were you expecting original research in a Slashdot comment?
The industry term for the mixed, melted contents of a reactor core is "corium". It's a mix of fuel rod assemblies ( fuel and fission products, additives, moderators, salts, and cladding), fuel rods (zirconium), and containment vessel (stainless steel), all compounded with reactor water and whatever additives were in it. In a theoretical worst case, you get to add in some concrete from the floor of the reactor building, too.
In short, about half the periodic table.
Whenever talk turns to Fukushima, I'm always surprised at how little is known of the dark side of America's nuclear history.
Did you know the first meltdown in the U.S. was in Los Angeles? And the reactor had no containment.
https://www.youtube.com/watch?v=-_FCvbc0cNE
https://www.youtube.com/watch?v=DPk9kEaSyAY
Did you know about the Santa Susana Field Laboratory and it's ten reactors? Four of which had nuclear accidents.
http://en.wikipedia.org/wiki/Santa_Susana_Field_Laboratory
And this is only a very small part of the story. Be glad you are not raising a family in Canoga Park.
In short, about half the periodic table.
Not the best part, though.
Slashdot, fix the reply notifications... You won't get away with it...
Gloop?
Actually "gloop" has almost all letters of the word "google". That was a hint as how to find out...
Slashdot, fix the reply notifications... You won't get away with it...
You've got to remember that these are just simple sub-atomic particles.
They are unstable. Common clay of the elements.
You know... Muons
Gloop is an industry term.
Gloop isn't fair.
Gloop is tough on stains.
Gloop doesn't know right from wrong.
Gloop tastes like gravy.
Gloop almost made the periodic table.
Gloop can't or won't.
Gloop has a secret.
Gloop speaks four languages.
Gloop is low in fat.
Gloop is a lover, not a fighter.
Gloop wants to talk to you.
Gloop stays the course.
Gloop cares about the environment.
Gloop is everywhere.
Unlike porn, which yada yada rimshot hey-ooh!
nope. Absolutely the worst, most vile, toxic and unpleasant half.
The rest is made up of unicorn farts, smurf cum and angel titty.
Political debates have me rolling my eyes so much I think I got optical whiplash. I should sue. - Foamy The Squirrel
I thought the term of art was Corium
Not really.
In reality, under a complete loss of coolant scenario, the fast erosion phase of the concrete basement lasts for about an hour and progresses into about one meter depth, then slows to several centimeters per hour, and stops completely when the corium melt cools below the decomposition temperature of concrete (about 1100 C). Complete melt-through can occur in several days, even through several meters of concrete; the corium then penetrates several meters into the underlying soil, spreads around, cools, and solidifies.
I saw some documentary on TV not too long ago, that talked about using muon detectors to look for fissionable materials being smuggled for terrorist purposes hidden in transport containers.
In theory, theory and practice are the same; in practice they're different. (Yogi Berra & A. Einstein)
Radon's transform is really useful here
Underground mobile transport was to permit the usage of dummy silos, straining Soviet targeting and soaking up warheads.
That is an actual use, of CMT, unlike the fantasy of detecting deviations in muon flux through thousands of kilometers of dense, proton-rich material.
Primer from LANL:
http://www.lanl.gov/quarterly/q_spring03/muon_text.shtml
Muons are deflected by heavy materials like nuclear waste. The object your looking for does not need to be between the detector and the atmosphere (implied to be underneath the object). The object can and that would work in the sense that you would have a blank spot in the detector corresponding to where the waste is. Instead they're relying on the muons being deflected by the waste where detectors on the surface can pick up those muons and use the array of collects and deflected muons to triangulate where the waste is located.
"Lack of speed can be overcome. In the worst case by patience." --Znork
Think "anomalously long backscatter times"/"anamalous diffusion of backscatter" for energetic cosmic rays. You can refine the specificity for the location utilizing synthetic aperture techniques, but you end up with very thin stripes for each pass over the scanned region. I *did* say "long term observation"...
Note that the Fukushima detectors are a pretty long ways away from the reactor itself, as well as the containment vessel, compared to straight tomographic techniques used to examine cargo containers, say in Oakland.
NB: These days, it's pretty obsolete as a technique, and we use neutrino tomography instead, but there are enough "dark spots" that it's not possible to cover everywhere with the technique. Interestingly, Vernor Vinge "outed" the neutrino tomography technique in his novel "The Peace War", although his details are a bit hand-wavy and wrong.
Generally we don't have to worry about being shot down when we fly a constellation of high altitude aircraft over North Korea without their permissions in order to create a synthetic aperture large enough to be meaningful, so it's OK for filling in the dark spots there. You wouldn't want to run the same flights over Russia, even at 90,000 feet these days.
PS: In case you missed it, there was a story the other day bemoaning the lack of noble gas detectors to detect by-products of fission plant operation, but they also wanted some better generalized climatological models (read: give us lots of money for supercomputer hardware to play with) in order to determine the origin, should noble gasses be detected with their new detectors.
Yes, you can triangulate locations of dense material when you can move the detector all around a potential target, exactly as was said in the comment you replied to in regard to scattering based tomography. You don't need to cover all 4 pi steradians around it, but do need a lot of different angles and collection time, and it works better when you can get right behind it, because by far the most scattering is low angle scattering.
But the parent comment about moving missiles around is complete BS. Scattering based muon tomography was not around 40 years ago. And even if so, you would not be able to distinguish a weapon sized lump of dense material without being practically in the same room. It is not something the Soviets could do from orbit or from their own soil when looking at American weapons.
I don't know, it could be worse.... There could have been sizeable amounts of elemental fluorine and chlorine too..... And other very nasty things...
Think "anomalously long backscatter times"/"anamalous diffusion of backscatter" for energetic cosmic rays.
First off, the mean lifetime of relativistic muons seen in the atmosphere means they only travel an average distance of 600 m before decaying. Backscatter will shorten that even due to energy transferred to what it hit. Backscatter is already a lot weaker than small angle scattering. That greatly limits you signal you'll get at a plane or higher, by orders of magnitude compared to tomography done on the ground.
Second, you'll get backscatter from a lot of other things, and will need extremely high resolution to distinguish something that small, at a large distance. If you had that type of resolution, astronomers would want to talk to you.
You can refine the specificity for the location utilizing synthetic aperture techniques,
Synthetic aperture is useless if you don't have timing and/or phase information. There is no way to get phase information with a muon, and you're not going to squeeze a muon source into a satellite or plane, so everything is illuminated by a constant influx of muons with no control of the source.
neutrino tomography instead
I'm actually quite close friends with people on a couple different neutrino detector experiments, and unless the government has some huge hidden and classified detector, this is BS. You can't locate antineutrinoes from large reactors now using the largest, most resolved detectors we have now. They can't even manage to do tomorgraphy of the Earth's core yet, and are working on building more detectors to start to get that kind of resolution. You're not going to get anything like that into a plane or satellite, so synthetic aperture is of no help (not that it would help any without timing information).
It may show up in some fictional novel, but that is still what it is, fiction for some time. Sorry if this is just a case of you mis-remembering something you saw or read once, but despite using a lot of the right words, the picture you paint is just sci-fi, and it makes it look like either you, or the person you got the info from, are just cranks or knowledgeable trolls.
A 'China Syndrome' event is not possible in Japan.
The gloop would come out somewhere around South America.
Have gnu, will travel.
Fluorine and chlorine are trivial to handle compared to high level radioactive isotopes.
There are few things more unsettling than a substance where a dust sized speck can fry you within a few hours (if inhaled or otherwise ingested) or days (stuck on your exterior).
chlorine and fluorine are chemically active and highly corrosive. They will burn mucous membranes on contact as they react with water to form hydrochloric and hydrofluoric acids. Plutonium is very dense and a cumulative poison with similar bioreactivity to lead. Its radioactivity is a relatively minor issue unless ingested or inhaled, at which point it can cause damage to genetic material - any of which that survives can become malignant.
Political debates have me rolling my eyes so much I think I got optical whiplash. I should sue. - Foamy The Squirrel