What sp writes is accurate, Larry. The facilities were not "purposely" designed to shield against a large aircraft collision. They were designed to fend off an errant smaller craft, and then some. It just so happens that the "and then some" would be very effective against larger aircraft as well.

Nothing in the civilian world is really designed against large craft impact without prior knowledge that a large craft would, could, and likely will be used as a suicide missile. The facility designs for reactors is for the containment, the control, and the avoidance of accidents, not purposeful attack.

This is mind, how many reactors could stand up to, say, 3 Boeing 707s, one after the other?

I would think not very many...

Of course it would be a real trick just getting 3 707s today. You would probably need certified pilots with scheduled maintenance flights.

Doable, but very complicated.

Another approach (for the small plane scenario and the 10 mile no-fly zone) would be gassing the facility from the air for a ground invasion (Auric Goldfinger style). Of course this only works with highly concentrated chemicals. It would have to be incredibly dirty to complete the task in a timely manner, thus allowing the facility to be penetrated before authorities could arrive on the scene.

Again, doable, but very complicated.

Dan