I hate to be doom and gloom here, but banning weapons doesn't work.
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I applaud the sentiment behind banning nuclear weapons, I really do. It is a wonderful dream - but I suggest tilting at windmills you have a chance of hitting.
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Some history is in order here. Throughout recent history (say since the repeating rifle) there have been efforts to "limit" or ban weapons of a certain type.
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Particularly after World War 1, (the Great War at the time), there was a huge push to ban mechanical weapons that devastated people and land - think Gatling guns, machine guns, tanks, and other efforts to limit these weapons and navies.
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It failed because anyone who "cheated" would gain a huge tactical advantage (this is one of the ways Hitler's German was able to run over Poland and the Sudetenland of Czech part of Czechoslovakia).
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Now amplify that advantage for nuclear weapons. Would any of us trust that North Korea, Pakistan or China would destroy their weapons - or would we hold some back in reserve in case they didn't? Would any reasonable country believe the US would destroy our weapons?
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So the advantages of non-compliance would force rational state actors to cheat.
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And then there is the deterrent effect of nuclear weapons. It has helped mitigate some potential war zones. In an asymmetrical world, Nuc's keep Israel from being overrun. They also allow countries (aside from the US) to spend a LOT less on defense than they would otherwise. If Russia had to have a standing army to defend all it's borders, it would be massively expensive - moving funds away from development. The same with India or North Korea. If nuclear weapons miraculously disappeared tomorrow - military spending would go way up.
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Also war would be a lot more palatable. I mean the US sent armies into Iraq, Afghanistan, Somalia, Lebanon, and Grenada in the past few decades. If we weren't threatened with Nuclear War we might have easily attacked Russia or China. Or China might have invaded Taiwan without the threat of US Nuclear Response. So I think "banning" nuclear weapons might have the unintended effect of increasing traditional wars (if it could be worked out).
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In short, it is an impossible dream and I am not sure it is smart.
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Finally, the real threat is from non-traditional actors (terrorists or stateless entities) that the ban will not effect.