The used fuel discharged from nuclear power plants constitutes the main contribution to nuclear waste in countries which do not undertake reprocessing. As such, its disposal requires isolation from the biosphere in stable deep geological formations for long periods of time (some hundred thousand years) until its radioactivity decreases through the process of radioactive decay. Ways for significantly reducing the volumes and radiotoxicities of the waste and to shorten the very long times for which the waste must be stored safely are being investigated. This is the motivation behind the partitioning and transmutation (P&T) activities worldwide. This paper addresses the potential impact of P&T on the long-term disposal of nuclear waste. In particular, it evaluates how realistic P&T scenarios can lead to a reduction in the time required for the waste to be stored safely. The calculations have been done independently by three research groups: ITU and FZK in Germany, and by the CEA in France.

An advanced process has been developed on a laboratory scale at the Institute for Transuranium Elements (ITU) for the fabrication of transmutation fuels and targets. The process consists of the fabrication of highly porous beads using a sol-gel method, their infiltration by a nitrate solution of the relevant actinide, and calcination, compaction, and sintering to give the final product pellets. This work presents the results obtained in the qualification of this process whereby dense partially-yttria-stabilized zirconia pellets with high contents of cerium and plutonium have been fabricated.

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