If it were tritium, the half-life would be an issue. Tritium's half-life is only 12.33 years, but U235's half-life is 704 M-years. I don't think contamination is much of a problem. U's pretty dense. Surface contamination would be cleaned off during the machining process.
CNN's now saying that it hasn't been determined to be weapons-grade yet...
I get the impression that the cylinder being shown is the 33 pound lump of uranium. Uranium's density is about 19 g/cc, so 15.7 kg would take up 826 cc. If the cylinder is 25 cm/10 in long then it would be about 6.5 cm/2.5 in in diameter. That seems about right to my uncalibrated eye.
The clearest picture of it I've seen is [link|http://www.msnbc.com/news/814321.asp?0si=-|here] on MSNBC. The orange stuff seems to be old celophane tape or something similar. On the right it seems to say something like "PRIMARILY TOURANUON" which makes no sense to me.
It'll be good if/when we have more information about this thing.
[edit](U235's half-life is 704 Myr, not 7.04 Myr as posted originally. Sorry.)
Cheers,
Scott.
(also, it's Deutschland. :-)