Update on CIRCE Mechanical Toolbox for Fusion Magnet System Analysis

Future fusion devices rely on the use of high-field magnetic systems built with high-temperature superconductors (HTS). The interaction between intense magnetic fields and large operating currents induces significant mechanical stresses, which limit the deployment of HTS in fusion magnets. Efficient and reliable analysis tools are therefore essential to evaluate mechanical integrity during the early stages of design. CIRCE (Cast3M Investigation and Research for Coils mechanical Evaluation) is a mechanical toolbox developed to provide fast and parametric assessments of coil systems. It combines simplified electromagnetic and mechanical formulations within a fully parametric framework, enabling magnet designers to identify critical stress regions and determine optimal coil shapes for a given plasma configuration. This paper presents recent updates to CIRCE. A new regularized Biot-Savart formulation enables Lorentz force computation for arbitrary coil geometries. The mechanical beam model has been enhanced and extended to support non-planar coils. Additionally, a local 2D axisymmetric model has been implemented to evaluate transverse stresses at the conductor level. These improvements have been applied to the DEMO-LAR Tokamak and HELIAS 5-B baselines.