Minimally Intrusive Verification of Deep Nuclear Warhead Reductions: A Fresh Look at the Buddy-Tag Concept

Next-generation nuclear disarmament treaties may place limits on the total number of nuclear weapons in some arsenals. Verifying such agreements would require the ability for inspectors to count individual warheads. Attaching unique identifiers directly to nuclear warheads could be problematic due to a range of concerns by the host related to safety, security, and intrusiveness. To resolve this dilemma, we revisit the so-called “Buddy Tag” concept first proposed by Sandia National Laboratories in the early 1990s. Buddy Tags are tokens that must accompany each treaty-accountable item and be produced with- out delay. In an arms-control context, each treaty partner would receive a number of Buddy Tags, one for each accountable item. Verification would rely on short notice inspections. Sensors on the Buddy Tag would show that it had not been moved to the inspected site af- ter the inspection was declared (e.g., within the last 24–48 hours). If the inspector counted more (or fewer) TAIs than Buddy Tags at the inspected site, a treaty violation could be as- serted. Using a number of single-site inspections, an inspecting party can hold the host at risk for discovery of violating the treaty at an enterprise level by possessing more TAIs than the treaty allows. This paper summarizes the performance requirements for an ad- vanced Buddy Tag that is being developed as part of this project, reviews the proposed conduct of operations, and discusses initial results obtained for a first prototype.