In summary, from the point of view of the physics, most options seem to be viable, but the consequences on the fuel cycle (cost, feasibility, doses to workers, etc.) seem to be more crucial. For example, apart from an increase of costs due to the need to over-enrich the core fuel of a LWR and some limitation in the amount that may be loaded to avoid a deterioration of the reactivity coefficients, the recycling of grouped TRUs in this type of reactor is practically excluded due to the huge increase of neutron doses at fuel fabrication.

Similarly, in the case of FRs, the constraint on grouped TRU recycling due to neutronics and core safety is in principle manageable. However, even if much less dramatic, the consequences for the fuel cycle (e. g. at fuel fabrication) of the TRU loading in the fuel can be significant with dedicated TRU-burning FRs (critical or sub-critical, heterogeneous or homogeneous) being the most affected.

The development of appropriate fuels, loaded with more or less TRUs, has proven to be a very severe task; this is especially the case for viable U-free fuels (also known as fertile-free fuels or inert matrix fuels). In any event and whatever the strategy, MA-loaded fuel development is a very significant challenge that needs R&D and the availability of appropriate irradiation facilities.

Finally, the transmutation of LLFPs does not seem to be realistic in view of the limited transmutation rates and the burden, in terms of reactivity loss during the cycle, on core performance.