Actinide-Bearing Fuels and Transmutation Targets

Materials for Sustainable Nuclear Energy: A European Strategic Research and Innovation Agenda for All Reactor Generations

“…Spent fuel long-term toxicity can be greatly reduced by adopting advanced nuclear fuel cycles that foresee the extraction of minor actinides (MA), namely Am, Np and Cm, later introducing them in fresh fuel for their transmutation in fast reactors [28]. This can be achieved in homogeneous mode, by diluting a low content (a few % of heavy atoms) of MA in conventional fast-reactor fuel, exploiting the structural similarity of the various actinide oxides and their reciprocal solubility [28]. This has minimal impact on reactor safety parameters and facilitates qualification [28,124], but implies that all fuel elements will contain some MA.…”

“…This can be achieved in homogeneous mode, by diluting a low content (a few % of heavy atoms) of MA in conventional fast-reactor fuel, exploiting the structural similarity of the various actinide oxides and their reciprocal solubility [28]. This has minimal impact on reactor safety parameters and facilitates qualification [28,124], but implies that all fuel elements will contain some MA. Heavy shielding and remote handling will therefore be necessary for fuel fabrication and assembly production, because MA exhibit high neutron emission, thermal power and toxicity.…”

“…Another virtue of these systems is that, since Pu is eventually removed from the fuel for reuse, they enable the long term radiotoxic impact of waste to be abated. This is especially true when minor actinides (heavy elements present in low quantity, but significantly contributing to long term radiotoxicity and heat production) are transmuted in the reactor itself into shorter lived fission products, after sufficiently high burnup [28], or using dedicated devices such as accelerator driven systems [28,29]. These practices can reduce the volume of remaining radioactive waste and the emitted heat flux by one order of magnitude, and the radiotoxicity timespan to a few hundred years [28], thereby significantly relieving the requirements of anyway necessary geological disposals.…”

“…This is especially true when minor actinides (heavy elements present in low quantity, but significantly contributing to long term radiotoxicity and heat production) are transmuted in the reactor itself into shorter lived fission products, after sufficiently high burnup [28], or using dedicated devices such as accelerator driven systems [28,29]. These practices can reduce the volume of remaining radioactive waste and the emitted heat flux by one order of magnitude, and the radiotoxicity timespan to a few hundred years [28], thereby significantly relieving the requirements of anyway necessary geological disposals. Moreover, GenIV reactors will feature high safety standards because the use of liquid metals (generally either sodium or lead alloys) or molten salts as coolants enables operation at atmospheric pressure and facilitates the design of passive systems [30].…”

Preliminary Multi-Physics Performance Analysis and Design Evaluation of UO2 Fuel for LBE-Cooled Subcritical Reactor of China Initiative Accelerator Driven System

“…Furthermore, fuels to be used in ADS systems dedicated to MAs transmutation can be described as highly innovative in comparison with those used in critical cores (Maschek et al, 2008). Irrespective of the recycling method considered, MAs are transmuted preferably in their dioxide form of cubic fluorite structure (Delage et al, 2020;Carbol et al, 2012), which, based on the lengthy experience available on MOX fuel, is known to provide good stability under irradiation (Pelletier and Guérin 2020). Because of the historical experience and knowledge gained on oxide fuels for LWR and FR, MA oxide fuel forms have been preferentially investigated in Europe and emerged as the primary option (Delage et al, 2011), which was also considered as a primary option for the Chinese ADS fuels research and development (R&D).…”