ireckon

A 100 megaton A-bomb is a whopping big bomb. Nobody plans on doing that stuff these days. Most atomic explosives are at much smaller levels. US bombs are typically not larger than 100 kT for a lot of purposes. The biggest French bomb is 300 kT. The old screwball days of massive hydrogen bombs are largely gone ... military generals realized there is no point in destroying the whole Earth.

It's almost inconceivable that terrorists could smuggle a bomb yielding 20 kT - or at least the task would not be easy. It might be the kind of thing they could do in Pakistan, but it's a major challenge for them in a western country. Take a look at the physical dimensions of the Hiroshima bomb. That's the size of a crude weapon with that power. It's just too large for anyone to smuggle anywhere.

So yes ... there would be a problem with contamination and fallout. But overall, the problem is something that could be managed. That's my impression.

Pete2