I have often heard—and had it reinforced by watching The Sum of All Fears—that the fissionable material in nuclear weapons has a kind of “fingerprint.” That, because of the differing levels of different isotopes resulting from different generation/processing facilities, you could tell where each warhead’s plutonium or uranium came from. To the degree of accuracy that you could sometimes even tell which reactor in a particular nuke plant produced the material, and in which month of which year—and that you do so just by analyzing the fallout/residue from a nuclear blast.
Is any of this true?
Can you, in fact, distinguish nuclear materials in such a way?
Can you do so just from the fallout/debris of an exploded nuke?
Is there some huge database (at the IAEA?) where every country and facility’s nuclear “fingerprints” are kept?
If all this is true, how difficult is it to analyze/match these fingerprints?
How long does it take?
What sort of equipment (gas chromatograph? mass spectrometer? something the size of a refrigerator? something the size of a breadbox?) do you need?
What sort of site samples do you need from the blast zone to make such an analysis?