Neutronics assessment of a liquid metal lithium breeding blanket for the inertial confinement fusion reactor TARANIS

Sammanfattning

GenF, a French start-up company, is developing key technologies to enable the commercialization of the direct-drive inertial confinement fusion (ICF) reactor Taranis. One of the major engineering challenges in fusion power plant design is the breeding blanket which must enable tritium self-sufficiency, and host and remove nuclear heating. As no ICF specific neutronics study assess the performances of liquid metal natural lithium with no neutron multiplier as breeding medium, a parametric neutronics Taranis model was developed using the open-source Monte-Carlo code OpenMC. The model features a point isotropic polyenergetic source derived from TROLL simulations corresponding to a typical Taranis target: a 5 mg deuterium–tritium (DT) fuel capsule ignited with 600 TW of laser power. The simplified geometry is spherical and composed of a 5 m radius reaction chamber, followed by a 1 cm tungsten first-wall (FW), 3 cm 316L stainless-steel structural material and a 1m thick liquid metal natural lithium breeder. A successful cross-team/cross-code benchmark has been performedon the obtained radial profiles of neutronics key performance indicators (KPIs). The obtained tritium breeding ratio (TBR) is greater than 1.15, demonstrating that tritium self sufficiency is achievable using this baseline, while maintaining a nuclear heating of 4.11 GW and a fusion energy multiplication factor of 101%. However, the radiation damage estimated over one full power year (DPA/FPY) in the structural material reaches 82 DPA/FPY, which is superior to the life time DEMO radiation criterion, fixed at 20 DPA. Finally, the optimal Li-6 enrichment level to minimize blanket thickness has been determined at 43.4 at%. This work concludes that liquid metal natural lithium appears as a promising baseline for future ICF reactor development.