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Robot Saves the Day at Radiation Lab
An anonymous reader writes "Nature.com is reporting that records released this week by the US defense department read almost like a bad movie plot. Back in October a high-security radiation lab had a cylinder filled with radiation get trapped in its delivery tube network. Fortunately a specially designed bomb-disposal robot was able to retrieve the canister before the radiation was able to eat its way free.
chown -R us ~you/base
The cobalt was stuck for three weeks. The warning sirens are a government regulation, something to do with informing workers of radiation source. The robot was brought in, but it took a while for the team (from Albuquerque) to get ready to go to White Sands with their robot.
This slashdot article is dupe. See sandia.gov for more poorly written details.
No, they wouldn't be fired; they work at a national lab :-P Seriously though, electronics that can handle intense radiation are expensive.
The article that I read several days ago said that they use the cobalt-60 to test radiation resistance... they want to see the effects that high radiation levels will have on various pieces of military and civilian hardware. They set up their test gear, shuttle in the cobalt via pneumatic tube, let the gear cook in the extremely intense radiation, and then shuttle the cobalt back into a 'safe' area. I believe the original article claimed that cobalt is good for this, because it doesn't make the whole area permanently radioactive, though I'm not familiar with the reason why. (gamma radiation, maybe???)
... radiates. And it was ALREADY free, that's why the needed the darn robot. That whole testing area was absolutely lethal to human beings, even in heavy protective gear. Even the robot couldn't survive it very long... they thought 50 minutes. In actual practice, it lasted longer... but the movement system did fail, so they had to drag it out with a rope.
The writeup on the article is misleading. Radiation doesn't 'eat its way free'... fer chrissake, people! Acids eat things. Radiation just
To the person asking about building a Faraday cage around it.... as far as I know, a Faraday cage isn't an absolute barrier, it's just a very strong one. It attenuates a signal by a very great deal, making signals interception very difficult. But in this case, the 'signal' (the cobalt) is so incredibly powerful that a Faraday cage would just take the edge off, as it were. If my limited understanding of radiation is correct, it'd be just about as effective as sunglasses in front of a supernova. (and I'm not sure that Faraday cages even *work* at these frequencies... the radiation might just punch right through the shield material.)
It isn't the shape of the Faraday cages that's special. It's the size of the mesh. The mesh has to be significantly smaller then the wavelength of the radiation you are trying to keep out. Microwaves have a wavelength of 1-300mm. The wave-length of gamma rays is less then 0.00000000001mm. That's much smaller then the distance between atoms in a typical solid, so the idea of a mesh becomes kind of absurd.
I doubt that the problem with shielding is communications. After all you could put the shielding on the side facing the radiation, and leave the side towards the crew open. Gamma radiation doesn't go around corners. Or, as others have suggested, you could just run a cable to the robot. I think the actual problem is weight. Lead is heavy. You might be able to pile a ton of lead around the cpus and memroy, and just crank up the horsepower of the motors. However, by their very purpose you can't put the sensors behind lead sheilds, since all they would see then would be the lead shield. Not very helpful.
Mayak, where the Soviet Union pumped out tens of tons of plutonium for nuclear weapons. Some info on how the Soviets fixed the 'it got stuck' problems - no fancy robots for them. http://www.thebulletin.org/article.php?art_ofn=so9 9larin
"A complete repair would have taken at least 12 months..."
""That meant that the irradiated uranium fuel had to be pulled up by hand into the central hall of the reactor and placed in a special storage area. Then, when the repair was finished, the elements had to be loaded back into the reactor. Over time, we unloaded and reloaded 39,000 fuel elements. All of the plant's personnel took part in this work and they received huge doses of radiation. The repairs were finished in two months."
"several hundred kilograms of freshly irradiated nuclear fuel got stuck--men from everywhere in the plant were called out, and one after another they used long steel rods to push the elements into the apparatus. The only protection they had was cotton overalls and gloves."
Domestic spying is now "Benign Information Gathering"
Actually Cobalt 60 is a Gamma emitter. Gamma is EM but very high frequency. The majority of the radiation from it is not particle radiation unless you count photons are particle radiation.
The holes in the shielding on a microwave have to be smaller than the wavelength of the microwaves. Gamma has a wavelength smaller than visible light so the holes would have to be too small for even light to pass through. It is also a lot more energetic so the thin metal shielding used in a microwave wouldn't be of much use. So a faraday cage "could" work if it was thick enough and had small enough crystal structure the be effective the only problem is I don't know of any material that meets those requirements off the top of my head. A high density shield of say, lead would be far simpler.
See my blog http://ilovecookes.blogspot.com/ for light hearted technical information.
Gamma radiation is very high energy (and short wavelength) EM radiation. Neutrons are...neutrons. Alpha particles are Helium nuclei, and Beta radiation is positron radiation. That's about it for the types of radioactive decay radiation [sic].
A sheet of paper is sufficient to block alpha particles. A thin sheet of wood will effectively block beta radiation. Lead works well for neutrons, and a LOT of lead is required for gamma radiation.
Read back on the experiments with that B-36 that had a nuclear reactor on it. The crew area at the front was protected from the otherwise unshielded reactor core by something like 20 *tons* of lead...