Political disarmament is very possible but a practical and verifiable agreement for the elimination of nuclear weapons is, in my opinion, a fleeting illusion. You cannot undo the discoveries of an entire area of science nor can you really stop nations who are determined to acquire these weapons.....Iran for example. The promise of "power" a nuclear weapon can bring to a nation, both real and imagined, is simply unequaled and therefore the quest for this "power" by some in all consuming. These nations are not thinking peace as they move to acquire these weapons....they are thinking Power!
I believe there is only one example of a nation divesting itself of nuclear weapons......Canada gave up it's nuclear weapons in the early 80's and turned their arsenal over to the Americans.
While this is a great example of a nation standing for their principles most people are totally unaware that this even occurred.
Your question is very interesting and thought provoking. I look forward to reading other responses. Thanks