According to the article, "Servicemembers from the tank brigade that found the crater have confirmed that background radiation levels at the site are normal", and "Background radiation levels in Chelyabinsk remain unchanged, the Emergency Ministry reported".
I am no physicist. But assuming that we can take these reports at face value, doesn't that rule out the possibility that the meteorite was intercepted by a nuclear device?
Depends on how good their equipment was. The small boosted plutonium warheads used in that kind of missiles are extremely clean (they are meant to be used over their own territory, after all...), and I think that after the kind of wide dispersion you get when the surface of the object ablates away as it falls there might not be much more than a small blib over the background left.
However, based on my very limited knowledge, I think that the Russians are supposed to only have operational Gazelles in a ring protecting Moscow, and those shouldn't have the range to hit anywhere near Chelyabinsk.
They experimented with it, publicly declared it a success, but said they weren't going to do it, and proceeded to use the tech on the far side of the country. Pechora-Kama I think was the original project. Maybe they did, maybe they didn't, but the locals I've met (Kazakhstan) insist that they did.
It wouldn't surprise me if the Russians were looking at the same thing, but it should leave some fairly telling clues behind. At the very least you can see plowshare craters littering Nevada on google maps (in a nice grid pattern in some areas, just search for "Sedan crater" and zoom out a little), I would expect similar to be somewhere in Russia if they were doing the same.
A 10kt yield at altitude wouldn't leave a crater, either...
Unless it was used to blow up a large chunk of rock which then proceeded to fall to the ground. In that case, you'd get a crater, but you'd also get the radioactive material.
I am no physicist. But assuming that we can take these reports at face value, doesn't that rule out the possibility that the meteorite was intercepted by a nuclear device?