The concrete shield thrown up to block radiation escaping the Chernobyl nuclear power station after it exploded in 1986 is collapsing and needs urgent reinforcement, Russia's atomic energy minister said April 22, 2003. A radiation level check is shown being taken outside the concrete sarcophagus housing the nuclear power plant's fourth reactor, April 21, 2001. (Gleb Garanich / Reuters)
There are birds nesting _inside the sarcophagus_. It doesn't stop any radiation getting out (not even Alpha particles), it mainly keeps a little rain off of it.
Cites: google, from an original Washington Post article
Ah yes; another shining example of the competence of the Soviet industrial machine. IIRC this would be the second or third time it's had to be shored up, it had damage requiring repair back in 1988.
<lj user="mozgovaya"> did a bit of nuclear tourism on an assignment from her paper. The text is in Russian, but you might like the pictures.
http://www.livejournal.com/users/mozgovaya/117695.html#cutid1
http://www.livejournal.com/users/mozgovaya/116865.html#cutid1
http://www.livejournal.com/users/mozgovaya/116433.html#cutid1
http://www.livejournal.com/users/mozgovaya/116134.html#cutid1
http://www.livejournal.com/users/mozgovaya/115733.html#cutid1
http://www.livejournal.com/users/mozgovaya/115516.html#cutid1
http://www.livejournal.com/users/mozgovaya/115300.html#cutid1
It's ok. Even if the thing collapses and sends up a billowing cloud of radioactive dust, the
SovieRussians can just seed the clouds and cause all the radioactive particles to fall as rain on Belarus. You know, just like they did when the thing first exploded. Yeah.