The Development and Evolution of Nondestructive Assay (NDA) for International Safeguards

The verification of nuclear material inventories has been a key element of the Nonproliferation Treaty (NPT) for the past four decades. International safeguards inspection and verification implementation has made extensive use of nondestructive assay (NDA) measurements for the verification of the nuclear material inventory in the facilities in countries that are signature to the NPT as well as partial verification in the non-signature countries. This paper will describe the development and evolution of NDA capability for international safeguards during the past four decades. The measurement activities have evolved from primarily handheld and portable measurement equipment to installed systems with remote operation and continuous data collection. The focus of the paper will be on the experience and observations of the author rather than a review of the field.