There was a serious undercover US effort to prevent this. For example, half a ton of highly enriched, weapon-grade Uranium was transported from Kazakhstan [1][2

There was a serious undercover US effort to prevent this. For example, half a ton of highly enriched, weapon-grade Uranium was transported from Kazakhstan [1][2] in 199x; US also helped to prevent proliferation of weapon-grade Plutonium from the former test site [3]. There is also a non-confirmed suggestion that actual nuclear weapons become unusable if abandoned [4]. [1]: http://nsarchive.gwu.edu/NSAEBB/NSAEBB491/ http://nsarchive.gwu.edu/NSAEBB/NSAEBB491/ [2]: http://www.washingtonpost.com/wp-dyn/content/article/2009/09/20/AR2009092002881.html http://www.washingtonpost.com/wp-dyn/content/article/2009/09... [3]: http://belfercenter.ksg.harvard.edu/files/Plutonium%20Mountain-Web.pdf http://belfercenter.ksg.harvard.edu/files/Plutonium%20Mounta... [4]: https://www.reddit.com/r/askscience/comments/4hh0h7/does_modern_nuclear_weapons_really_demand_active/ https://www.reddit.com/r/askscience/comments/4hh0h7/does_mod... edit: formatting, one more link