I just watched this excellent video called Always-Never: The Quest for Nuclear Safety, Control, and Survivability, which was produced in 2010 by the Sandia National Laboratories, the agency charged with ensuring that the US nuclear weapons stockpile remains safe and secure. (approximately 140 minutes)

Always/Never: The Quest for Safety, Control, and Survivability - Part 1

Note: If you need to disable a nuclear weapon, shoot it with a gun.