Nuclear waste impact reduction using multiple fuel recycling strategies

The paper deals with the use of a symbiotic cycle in order to minimize the LWR waste radiotoxicity, improving, on the same line, previous work[1]. The obtained results could be considered rather positive. We will show what is possible to do in this field using new original symbiotic cycles, remarkably improving the previous results. To reach this goal, we investigated innovative fuel cycles by using the gas cooled reactors (both thermal and fast). Their very favourable neutronic economy, supported by an appropriated spectrum, allows to transmute/fission actinides, in particular transuranic ones. In this frame, we developed a strategy based on an original symbiotic fuel cycle. We assume to begin using, as normal, enriched uranium in LWRs. The second step deals with burning all the actinides recovered from LWRs spent fuel in HTRs. One of the major innovative results after this irradiation consists in the strong reduction of the neptunium which represents one of the greatest concerns in long term disposal. The last one consists in adding, as fuel in GCFRs, depleted uranium together with all the residual actinides of HTR spent fuel. As final result we obtain a reduction of the Level Of Mine Balancing Time (LOMBT) from 250000[11] (LWR once through) to about 200 years (proposed symbiotic cycle). This research has to be considered in progress and needs of further confirmation mainly from a technological point of view.