Design Framework for Multiphysics Integration of DTT Divertor

The design and verification of in-vessel components for fusion devices require the coordinated handling of complex geometric constraints, multiphysics loads, structural integrity criteria, and assembly requirements. Among these components, the divertor plays a critical role, being subjected to severe thermal, electromagnetic, and mechanical loads while operating under stringent spatial and remote handling constraints. Ensuring the structural reliability of such systems demands a consistent and traceable integration of design and analysis activities across multiple disciplines. This PhD thesis investigates the application of an integrated design and structural verification workflow to the Divertor Tokamak Test (DTT) divertor. The work follows the complete design path, from parametric geometry definition to multiphysics load assessment and detailed finite element structural analyses, within an iterative and coherent process. Particular attention is devoted to the role of interfaces, load paths, constraints, and assembly-related effects in determining the mechanical response of the divertor system. Starting from a parametric geometric description, the workflow enables the management of strong couplings between geometric constraints, cooling system requirements, remote handling interfaces, and structural performance. This approach supports controlled design iterations and ensures consistency between evolving design solutions and the associated multiphysics loading conditions.A significant part of the work is dedicated to the assessment of electromagnetic loads induced by plasma disruption events. A broad set of disruption scenarios was analyzed with specific reference to their structural impact on the divertor cassette, leading to the identification of the most critical loading condition. The resulting electromagnetic force distributions were benchmarked against JOREK simulations, providing confidence in their use for structural verification purposes. The structural behavior of the divertor cassette was investigated using advanced finite element models, including detailed representations of contact interactions, preload application procedures, and load sequencing. Within this context, two alternative outboard fixation concepts—the knuckle and wedges systems—were developed and assessed. Numerical analyses were complemented by a dedicated experimental campaign, involving the design and realization of a representative test rig to characterize the mechanical response of the fixation systems.