Most IAEA safeguards concepts and technologies, therefore, were developed during the early 1970s when complete nuclear fuel cycles only existed in the nuclear-weapon States. In particular, uranium-235 enrichment technologies were only available in these States and the transfer of these technologies to non-nuclear-weapon States was carefully avoided. Reprocessing of spent fuel at that time was not considered to be sensitive - but in practice there was very little fuel fabrication from uranium-plutonium mixed oxide (MOX) and the use of plutonium in non-nuclear-weapon States concentrated on research devices for fast-breeder reactors (FBRs), such as fast critical assemblies. The situation has changed since. Several non-nuclear-weapon States have mastered the light-water reactor (LWR) fuel cycle. They developed their own enrichment capabilities based on ultracentrifuge technology and on other gas-dynamic processes (UCOR and nozzle technology), and gained considerable experience in spent-fuel reprocessing (e.g. EUROCHEMIC, WAK, Tokai Mura, and Tarapur). FBRs were also developed in several non-nuclear-weapon States and heavy-water production plants have been built there. This article analyses some foreseeable developments and their impact on IAEA safeguards. However, other - non-technical - developments that will significantly affect the future of IAEA safeguards must not be forgotten, the most challenging of which might be the full implementation of IAEA safeguards on all nuclear material in all peaceful nuclear activities in nuclear-weapon States
