Neutronic design analyses for a dual-coolant blanket concept: Optimization for a fusion reactor DEMO

Neutronic design studies of a conceptual DCLL fusion reactor for a DEMO and a commercial power plant

“…The results in terms of power density in the TF coil provided by these modifications are presented in figures 10(a) (outboard) and (b) (inboard). The first modification (model 2) has implied the use of 2 cm of tungsten (W) before the inner wall of the vacuum vessel (VV) as it was done in some of our previous simplified versions of the DCLL design [1]. Furthermore, the port wall has been enlarged (from 10 to 30 cm) in order to be comparable at least with the VV walls thickness.…”

“…Realistic 3D models are required for accurate calculations, particularly in order to avoid the overestimation of tritium breeding ratio [17] and nuclear heating values in in the first wall and front zone of the blanket, as well as the underestimation of the radiation damage and nuclear heating at the back [18], when 1D models are used. The model considered in this work is the detailed 3D version of a previously simplified DCLL [1]. Thus, the TF-coils, the divertor, the BB helium channels, the SiC flow channel inserts, the 'banana-shape' breeder modules, the vacuum vessel and the upper port are now realistically modelled in order to determine the influence of accurate 3D modelling on the neutronic performance.…”

“…In the previously published work [1], although the shielding optimization was not completely achieved, it was noted that an enlargement of the Eurofer first wall thickness could improve the global shielding performance of the design with no invalidating impact on the tritium breeding performance of the blanket. In fact, by adding 2 cm of Eurofer to the initial 1 cm of Eurofer thickness (total 3 cm of Eurofer) it was reduced the radiation at the TF coil, keeping the tritium breeding ratio (TBR) higher (being 1.18) than the threshold (1.1) needed for the reactor fuel self-sufficiency [25].…”

“…The comparison between the two detailed options (with 2 cm and 5 cm of Eurofer FW) and the similar old simplified version [1] is shown in the table 4 in which the basic responses tritium breeding ratio (TBR), peak nuclear heating (PNH) and energy multiplication (M E ) factor are stated. The comparison, also concerning two different Li enrichments (50% and 90% in Li-6) and a pure versus a realistic industrial LiPb composition [21], shows that 5 cm for the FW disables reaching the tritium breeding threshold (1.1).…”

“…Starting from the radial build obtained in a previous work [1] on a simplified version of a dual coolant lithium lead (DCLL) DEMO reactor in which the structures were substitute by homogenized toroidal concentric layers, a new analysis has been performed on a more detailed one, focusing the design developments on the maintenance and improvement of the shielding efficiency and the tritium breeding capability.…”