IAEA safeguards on plutonium and HEU

During the first 30 years of existence of IAEA safeguards, no highly enriched uranium or plutonium has been routinely used in the electronuclear fuel cycle. HEU was used in research reactors and in THTR or other prototypes, and plutonium was used in critical assemblies and prototypes for the future development of fast breeders. Electronuclear use of HEU seems, nowadays, more remote than it seemed 20 years ago, whereas plutonium is entering the fuel cycle economy, not through breeders, but through the use of MOX in LWRs. The paper will be devoted to the analysis of the influence of these industrial facts on the present and future evolution of international safeguards. Plutonium and HEU are the two 'direct use materials' in IAEA terminology. Although it is generally recognized that uranium between 20% and 60% or more, or plutonium with 20% or more of Pu 240 are not desirable for weapons manufacture, it was simpler for the Agency not to try to establish a threshold between 'weapons-grade' and non-weapons-grade materials, and to consider all of them as 'direct-use'. The paper will analyze the way in which such materials are safeguarded at present. The development of the use of plutonium in the electronuclear fuel cycle is not the only factor which leads to reconsider this situation. The prospect of weapons-grade plutonium being eventually consumed in electronuclear reactors, is another reason for doing so. Moreover, the sensitivity of plutonium contained in OLR fuels, increases with cooling time. The paper will analyze how IAEA's 93+2 program nearing completion could and should provide an opportunity for developing new safeguards approaches, best adapted to the industrial realities of the next century. (authors)