Preliminary design of the self-cooled lithium-lead SCYLLA blanket for a spherical tokamak

The future deployment of commercial fusion energy depends on several critical factors, among which the development of a feasible, safe, and integrated breeding blanket (BB) plays a prominent role. Since the company was founded in 2019, Kyoto Fusioneering (KF) has been developing its capability in advanced blanket design and technology development, focusing efforts on the advancement of its own innovative concept known as SCYLLA (Self-Cooled Yuryo Lithium-Lead Advanced), a self-cooled lithium-lead type blanket using silicon carbide composite (SiC f /SiC) as a structural material. Efforts to develop the SCYLLA design have employed a holistic approach focused on component modelling, identification of system interfaces between components and systems, and safety evaluation. In this paper, progress towards an application of the SCYLLA breeding blanket configuration, using a spherical Tokamak reactor as a reference, is reported. The description of the current architecture is provided, focusing on the main modifications to evolve the design from a pre-conceptual configuration to a more robust layout. From the point of view of interfaces and experimental R&D, a lithium-lead loop has also been developed by KF as part of its UNITY-1 facility, based in Kumiyama (Kyoto, Japan). This system includes comprehensive design and modelling of the tritium extraction unit. The chosen modelling strategy and the obtained results are reported in the paper and critically discussed.