I think you're all missing the significance of not observing an increase in radiation levels. That would absolutely cause a detectable rise in radiation if the site were active recently.
The obvious scenario would be enriched uranium getting blown up and scattered. But even if they removed the enriched stuff, doesn't everything else get blown to smithereens?
What about the U238? What about the uranium hexaflouride gas? What about contamination or contaminated parts from the equipment?