Preliminary Assessment of the Transmutation Potentialities for an ITER-like FW Sector Loaded with MA

Abstract

The fusion-fission hybrid reactor is a promising technology that is likely to assume an increasingly important role in the global energy scene in the coming years. This kind of reactor can use both the nuclear fusion and fission processes to produce energy: neutrons from fusion reactions are used to sustain the fission of a sub-critical system. This method allows to have an intrinsically safe facility, with higher efficiency than a fusion reactor itself and with a harder neutron energy spectrum than a fission reactor, which could be suitable for nuclear waste transmutation. This paper, in particular, analyzes a type of hybrid reactor for the transmutation of Minor Actinides (MA). Nuclear waste, in the oxide form, is inserted as an element of the First Wall (FW) of an ITER-like fusion reactor. The aim is to demonstrate the feasibility of the transmutation of the MA characterized by higher long term radiotoxicity into shorter lived nuclides. The neutron transport in a detailed 3D geometrical model of the ITER reactor (B-lite) was performed by MCNP6 code, while the transmutation of the MA loaded in a single element of the FW was performed by SERPENT2 code. A pulsed ITER-like irradiation scenario was used. The analysis, which must be considered as a preliminary feasibility study, lead to very promising results, which could be further improved with a longer DEMO-like irradiation scenario and a larger number of MA loaded (“fission waste”) elements loaded in the FW.