A Combined Electromagnetic and Mechanical Approach for EU-DEMO Toroidal Field Coils

Lorenzo Giannini,Daniela P Boso,Valentina Corato

doi:10.3390/app12062766

Abstract

The roadmap to fusion electricity of the European scientific program aims at the realization of the future DEMOnstration (DEMO) fusion power plant. In 2020, the pre-concept design phase of DEMO was completed, defining the concept and characteristics of the main magnets and structures of the machine. Sixteen toroidal D-shaped magnets, six poloidal annular coils and a central solenoid constitute the functioning system core. The reactor is subjected to huge mechanical loads, mainly due to the Lorentz force produced by the combination of the high magnetic fields and operative currents. As a consequence, the loading conditions are extremely demanding for the structural components, and it is crucial to complete a comprehensive static and fatigue assessment before proceeding with the next design iteration. This work focuses on the electromagnetic and structural analyses performed on the toroidal field coil system and its support structures to present the methodological approach developed. Exploiting the finite element method, a three-dimensional model has been defined to obtain the electromagnetic loads on the main time points of the reference plasma scenario and then transfer them to a related 3D structural model, corresponding to the discretization of the electromagnetic one. The structural model was used to obtain the displacement and stress fields at the various time points to perform the mechanical evaluation as well as the fatigue assessment.

Highlights

The Roadmap to the Realization of Fusion Energy of the European scientific program [1,2] includes driving experiments that aim to support the accomplishment of ITER and prepare the route for the future demonstration fusion power plant DEMO
The plasma is harnessed on torus-helical field lines generated by eighteen or sixteen Toroidal Field (TF) D-shaped magnets, arranged around the machine central axis; six Poloidal Field (PF) annular coils, which surround the TF coils, and a central transformer named Central Solenoid (CS), placed inside the machine bore
This paper focuses on the main studies and calculations completed at the end of the pre-concept design phase of the DEMO system [3,4]

Summary

Introduction

The Roadmap to the Realization of Fusion Energy of the European scientific program [1,2] includes driving experiments that aim to support the accomplishment of ITER and prepare the route for the future demonstration fusion power plant DEMO. Both ITER and DEMO are tokamak type reactors. As detailed in the following, the assessment has been performed implementing the Finite Element method by defining a parametrical electromagnetic model and a related structural model of the machine, which consist of the three main magnetic systems (TF, PF and CS), the structures, the auxiliary components and the bolted joint connections

DEMO: The Design and the Rationale Behind

The Electro-Magneto-Mechanical Framework