The MA content and composition (i. e. the mix of individual MA isotopes and elements) in the fuel are strongly dependent on P&T mode and objective; they are also key criteria for setting up priorities in terms of R&D programs and associated research facilities. Beyond the need of specific facilities for handling highly radioactive and high thermal load fuel, technological breakthroughs will be needed in areas such as fuel handling systems, discharge storage and transport systems prior to industrial upscaling.

The MA content can vary in terms of MA/Pu ratio from ~0.05 or less in the case of homogeneous recycling in FRs with CR ~1 (e. g. the scenario of Fig. 17.4), to MA/Pu —0.1 in the case of TRU minimization as unloaded from LWRs (e. g. the scenario of Fig. 17.6), up to MA/Pu —1 in the case of MA minimization in dedicated reactors (both ADSs or low CR FRs as in the scenario of Fig. 17.5). In the case of heterogeneous recycling where the MAs are placed in the target, the ratio MA/(Pu+MA) —0.2 is envisaged.

Separation of MAs into the constituents is another possibility that needs to be investigated; this could entail separation of one element or more, e. g. Am only or Am+Cm. These selective approaches, in particular the separation of Cm from Am could allow Cm to be sent for decay storage, given that its main isotope, Cm-244, has a half-life of only 18 years. However, the problem of the final recovery and management of the resulting Pu-240 should also be tackled.