The breeding potential of ‘flinabe’ and comparison to ‘flibe’ in ‘CLiFF’ high power density concept

Because of its low melting temperature (240 °C) and low vapor pressure, the molten salt LiF–NaF–BeF2 (Flinabe) with ratio 1:1:1 has been suggested as the front flowing liquid layer, FFLL (2-cm thick) in the Convective Liquid Flow First Wall (CLiFF) high power density concept (7 MW/m2 average neutron wall load, 10 MW/m2 max.). However, because of its lower Li concentration relative to LiF–BeF2 (Flibe, with ratio 2:1), its deployment as a breeder has been a concern. In this paper, we compare the local tritium breeding ratio (TBR) of Flinabe to Flibe in two arrangements: (1) as a FFLL and breeder in the blanket; and (2) as only the FFLL with LiPb/SiC conventional blanket following the FW. The impact of the choice of ferritic steel (FS) and SiC as the structural material on TBR was also examined. In addition, the paper discusses what constitutes a reasonable value for local TBR if all sources of uncertainties in the achievable and the required TBR are considered (e.g. modeling, nuclear data, burn up rate in the plasma, etc.)