Forgive me. Its a long thread.
Where have you said how people will be prevented from access to nuclear materials and centrifuges?
You can't because it's already been done. It's impossible to be perfect. You can be induced and influenced to not want something. You can never prevent it, unless the laws of physics says it's not possible, and even then I wouldn't hold my breath.
But there are these things called probabilities, you see.
If we can REDUCE (not prevent) the possibility of a terrorist getting his hands on a nuke from 1:100 to 1:1,000,000,000... that's a worthwhile change.
The fact that something isn't PERFECT is not reason to discard it, because NOTHING is perfect.
Obviously this whole deal requires an ability to see in colors other than black and white, as well an ability to understand cost/benefit analysis - things most folks on this forum do not possess.