[VOA]

I'd never say OBL won't be able to set off a real nuke inside the USA.
But as for the Russian suitcases, I think likelihood is low as many
professionals have talked about how these things are limited lifetime
in terms of usefulness.

I really do think theft modest amounts of really hot (short half-life)
redioisotopes from quite a few medical facilities...then aggregated and
set off as a dirty bomb in the worst-possible place is much more likely.

[DBrow]

VOA, the Manhattan Project, the Nazi nuke researchers, and the Japanese nuke team all rejected the dirty bomb concept as not being practical.

If I sprinkle Co60 on an acre of land so that you'd get a lethal dose in one year standing in the middle of it, you'd get a lethal dose in 12 minutes if you had it all scraped up in a shoebox with a stick of dynamite under it. That would be hard to deploy.

If you upped the amount of cobalt so that you'd get a lethal dose in an hour standing in your acre, then the initial package would be lethal in 5 seconds. You have a difficult design for transport and dispersal, especially now that lots of cops have rad detectors in the car or on their belt. Unshielded, that much Co will be detectable for blocks.

And it would take about 100 hospital's worth of Co60 to do that. I suspect that someone would finger you round about hospital #12.

That's considering a real threat. A media howling panic, though, is more likely. In that case, chopping up an old Coleman mantle and sprinkling it on a sidewalk (more than enough to give a Geiger counter the chuckles) would lead a prepared-in-advance media to panic half the nation. Like ABC and their 20 bags of fertilizer. Katie in the studio, and the standout reporter in a bright orange suit with a chattering counter- "It's reading 12, Katie, and that is terribly serious for the residents of Redondo Beach. President Hillary is ordering an evacuation of the southwestern United States, and President Obrador says that he'll commit troops to help..."