Don't be foolish.
Functional nukes have to have non-stop maintenance. The old nukes of the Soviet Union are long-since useless, save for those that Russia has expended substantial efforts to maintain. The half-life of most nuclear triggers alone renders such devices inoperable after more than 4 months without maintenance, and every day that passes adds to the impurities in the fissionable core and shell materials (while simultaneously reducing the fissionable mass available).
And you don't just add a little "extra" uranium or plutonium to bring your device back up past the critical mass point. You've got to replace your core and reshape your shell, something that the entire might of NAZI Germany couldn't do in WW2 in the best labs in Europe.
These are *NOT* devices that can be maintained in caves by students who eeked by in their University classes.
Uranium and Plutonium are some of the most brittle metals on this planet. Shaping them is a technical feat beyond all but a dozen state governments in the very best labs under the very best conditions. These metals are also subject to corrosion/rust, and their radiation greatly impacts the electronic circuitry and conventional explosives used in such nukes.
Moreover, if they had them, they would have long ago tried to use them. We would have already seen a "fizzle" in one of our major cities by now.
What you need to spend your time thinking about is how we are going to handle the ensuing panic after the terrorists get a nuclear fizzle/dirty bomb. That much they can and very possibly will do. Repeating Hiroshima is still beyond them, however.
And whether or not there was "chatter" between isolated terrorist cells prior to 9/11 is beside my point. My point was that the terrorists didn't go out of their way posting public messages in on-line forums bragging about 9/11 prior to the attacks. Surely most adults around FR can discern the difference between "chatter" and public bragging.
Likewise, this Daleel chap is making another intellectual mistake by not only bragging about a nuclear attack prior to it happening, but also by claiming that it will come in the way of an old, long-since expired Soviet nuke. Anyone schooled in even the basics of physics understands that 1980's era nukes are nothing more than dirty bombs today unless they have had non-stop maintenance in the best of labs by the brightest of highly skilled people.
Moreover, the third intellectual mistake by Daleel is that of bring up nukes at all. The U.S. has some 13,000 nuclear warheads on hand right now, and it would be genetic suicide for an external foe to give us an excuse to blast a continent or two or three (the only way to be sure) with those nukes.
So throw us into that briar patch...