Phase II


Working Group 4 focused on how to verify a declaration of the total number of nuclear weapons in a state, including both how to confirm the number present at declared sites and how to confirm the absence of weapons in other locations.  By analyzing and applying previous treaty verification regimes, Working Group 4 identified key criteria that would have to be considered to develop any future nuclear weapon accounting scheme, as well as potential frameworks that could be applied to undertake the verification of such a scheme. While the details of any verification regime would depend on the specific treaty requirements and the individual states involved, Working Group 4 has shown that a number of similarities exist across the many different verification regimes.