This is a Phase III deliverable from the Concepts Working Group.
The concept of “irreversibility” is central to any credible and sustainable effort to achieve and maintain a world free of nuclear weapons. In the case of nuclear weapons, this concept applies both at the micro- and the macro-levels. At the micro-level, irreversibility focuses on dismantling a single nuclear weapon and ensuring its components can never be reassembled to form another nuclear weapon. At the macro-level, irreversibility refers to a state permanently dismantling its nuclear weapons enterprise and then maintaining that status. In turn, analyzing irreversibility at the micro- and macro-levels makes clear that no one final, conclusive end-state of irreversibility exists but a spectrum of increasingly comprehensive levels of irreversibility that will accompany the process of nuclear disarmament. This is referred to as phased irreversibility.
