5. CONCLUSIONS • Civil reprocessing of spent fuel utilizing the PUREX process has been successfully practiced on a commercial scale for over 40 years without occurrences of diversion of special nuclear materials. These operations have been both for the purpose of spent fuel management and for the recovery of uranium and plutonium for recycle as UOX and MOX fuel for light water and fast reactors. Such a combination of spent fuel reprocessing and recycling is leading to benefits in ultimate waste disposal. • Measures to improve the environmental protection performance of commercial reprocessing plants over the past 20-30 years have greatly reduced emissions and waste volumes. • Growth in global nuclear electric generating capacity through this century will result in the production of increasing quantities of spent fuel that must be dealt with by reprocessing and recycling in order to minimize the stress on uranium resources and mitigate waste disposal issues and concerns with increasing inventories of plutonium and other fissile materials. • The deployment of multi-national fuel cycle centres, operating under an international framework and most effectively implemented in those countries with a sufficiently large civil nuclear energy infrastructure, can serve to ensure a sustained supply of nuclear fuel and related services under conditions in which the risk of proliferation of technologies related to the production of nuclear weapons is minimized. Reprocessing of spent fuel will be an important function of these centres. • A number of options exist for the recycling of spent fuel. Some, including those that avoid separation of a pure plutonium stream, are at an advanced level of technological maturity. These could be deployed in the next generation of industrial-scale reprocessing plants, while others (such as dry methods) are at a pilot scale, laboratory scale or conceptual stage of development. • Next-generation spent fuel reprocessing plants are likely to be based on aqueous extraction processes that can be designed to a country specific set of spent fuel partitioning criteria for recycling of fissile materials to advanced light water reactors and/or fast spectrum reactors. The physical design of these plants must incorporate effective means for materials accountancy, safeguards and physical protection. • Innovative reprocessing methods must be developed for the reprocessing of fuel types that may be utilized in the future; these fuels may differ substantially from the UO2 or MOX ceramics used in current light water reactors. Continued research and development on these methods must continue in view of the expected evolution in fuel and reactor types. • The design of advanced reprocessing methods must deal in a comprehensive manner with (1) safety, (2) the control and minimization of plant effluents, (3) minimization of the waste generation, (4) the production of stable and durable waste forms, and (5) economic competitiveness. International collaboration on the development of advanced reprocessing methods, considering the magnitude of the challenges, is essential to facilitate the future deployment of these technologies. • A detailed mass balance analysis of fuel cycle scenarios is required for the deployment of advanced spent fuel reprocessing methods, taking into account waste production, safeguards, and the impact of partitioning on downstream operations such as the fabrication of fuel for the recycle of recovered actinides.