International safeguards inspections by the International Atomic Energy Agency (IAEA) ensure the peaceful use of nuclear materials and technology. IAEA safeguards inspectors perform inspections at facilities to verify independently the declarations of a state about the use of its nuclear materials. The IAEA has three key objectives for states with comprehensive safeguards agreements: detection of any diversion of declared nuclear material; detection of any misuse of declared facilities for undeclared nuclear material production or processing; and detection of any undeclared nuclear materials and activities. The means of attainment of these goals has evolved over time. This chapter describes the concepts of safeguards inspections, and what a generic safeguards inspection regime at a generic example light-water reactor might look like.

International Safeguards Inspections

Ever since there has been spent fuel (SF), researchers have made nondestructive assay (NDA) measurements of that fuel to learn about its content. In general these measurements have focused on the simplest signatures (passive photon and total neutron emission) and the analysis has often focused on diversion detection and on determining properties such as burnup (BU) and cooling time (CT). Because of shortcomings in current analysis methods, inspectorates and policy makers are interested in improving the state-of-the-art in SF NDA. For this reason the U.S. Department of Energy, through the Next Generation Safeguards Initiative (NGSI), targeted the determination of elemental Pu mass in SF as a technical goal. As part of this research effort, 14 nondestructive assay techniques were studied . This wide range of techniques was selected to allow flexibility for the various needs of the safeguards inspectorates and to prepare for the likely integration of one or more techniques having complementary features. In the course of researching this broad range of NDA techniques, several cross-cutting issues were. This paper will describe some common issues and insights. In particular we will describe the following: (1) the role of neutron absorbers with emphasis on how these absorbers vary in SFmore » as a function of initial enrichment, BU and CT; (2) the need to partition the measured signal among different isotopic sources; and (3) the importance of the “first generation” concept which indicates the spatial location from which the signal originates as well as the isotopic origins.« less

S. J. Tobin

Papers

Technical Cross-cutting Issues for the Next Genera