Early design workflow and progress of Tokamak Energy’s high-field spherical tokamak fusion pilot plant for the US DOE Milestone-Based Fusion Development Program

This submission overviews Tokamak Energy’s (TE) contribution to the US Milestone-Based Fusion Development Program. Collaborating with US partners, TE will deliver a pre-conceptual design for a fusion pilot plant (FPP) based on a high-field spherical tokamak with high-temperature superconducting magnets. The focus of this contribution is on the early-stage design workflow and the current state of the project. It discusses TE’s emphasis on integration across all sub-systems and its influence on the overall design and proceeds to show the state of both engineering and physics work.

TE’s iterative workflow allows for early and rapid experimentation with machine design points. The starting point is PyTOK, an in-house whole plant systems code, which finds optimal design points across a range of parameters, whilst enforcing engineering self-consistency. A favourable design is taken into a rapid engineering and physics workflow, where the team assesses it more in-depth for up to two weeks. The assessments include neutronics for nuclear heating and tritium breeding ratio, initial plasma scenario and operating point analyses, magnet cage optimisation and plasma exhaust checks. By involving the entire team at this early stage, and not fully relying on an integrated code to analyse the design points, we ensure that an integrated and coherent device is carried forward to the next level of fidelity.