Unmaking the bomb: Verifying limits on the stockpiles of nuclear weapons

Verifying limits on the stockpiles of nuclear weapons may require the ability for international in-spectors to account for individual warheads, even when non-deployed, and to confirm the authenticity of nuclear warheads prior to dismantlement. These are fundamentally new challenges for nuclear verification, and they have been known for some time; unfortunately, due to a lack of sense of urgency, research in this area has not made substantial progress over the past 20 years. This chapter explores the central outstanding issues and offers a number of possible paths forward. In the case of confirming numerical limits, these in-clude innovative tagging techniques and approaches solely based on declarations using modern crypto-graphic escrow schemes; with regard to warhead confirmation, there has recently been increasing interest in developing fundamentally new measurement approaches where, in one form or another, sensitive infor-mation is not acquired in the first place. Overall, new international R&D efforts...