New concepts of Fast Breeder reprocessing

The Fast Breeder Reactor (FBR) is unique with regard to fuel efficiency. While the Light-Water Reactor (LWR) consumes roughly 200 tons of natural uranium per gigawatt-year of electricity produced, the FBR has a demand of only 1.5 tons uranium per GWa. An improvement of fuel efficiency by a factor of more than 100 has never before been realized in the development of a technical system. Resources of uranium are limited and would be exhausted within two human generations if consumed by LWRs. In contrast, if burnt in FBRs they will provide a reliable source of energy for many human generations. Chemical reprocessing of the nuclear fuel, and recycle of the energy carrier materials plutonium and uranium, is the key to achieve this outstanding efficiency. Based on the PUREX process which has proven successful in thermal fuel reprocessing, procedures and equipment have been developed to adapt this process of FBR fuel conditions, and to improve both its economy and environmental compatibility. This paper concentrates on the chemical aspects of these concepts; it discusses in particular the minimization of medium-active aqueous wastes by application of a 'salt-free' PUREX scheme in conjunction with electro-redox procedures, splitting and recycling of raffinate streams, improvements in fuel dissolution and off-gas purification, and the development of specialized construction materials. In addition, some guidelines to future R and D will be discussed. (orig.)