Articles techniques et présentations

In recent years, the optimization of high-temperature superconductors (HTS) has shown promising potential for developing advanced cable layouts aimed at the realization of practical fusion reactors. Despite their excellent performance in terms of electromagnetic and mechanical stability, reduced AC losses, and current-sharing characteristics, HTS cables are not immune to performance degradation because of the harsh environment present in a fusion reactor (i.e., neutron irradiation damage, irradiation-induced heating cycling mechanical loads, …). To overcome the huge efforts and costs and the great amount of time required to experimentally reproduce their response to a fusion reactor environment, Finite Element Method (FEM) has been proven to be a valuable option in the design of highly performant and space-saving cable systems. In this work, the COMSOL Multiphysics® software has been employed for analyzing the working condition of a fusion-like superconducting cable during a stationary D-T plasma operation. The model is built up via an electromagnetic-thermal coupling composed of four main blocks; the first section defines the Curvilinear Coordinate (cc) system, for considering the twisted geometry and its anisotropic physical (both thermal and electrical) properties. The second section is based on the Magnetic Fields (mf) interface and it is used for solving the magnetic flux density distribution, B=∇×A; the third section is a customized PDE, which solves the current density distribution through its vector potential, J=∇×T. These two blocks are fully coupled and contemplate the electromagnetic part. The fourth block is based on the Heat Transfer Module and concerns the superconducting performance degradation due to the neutrons and the secondary particles' interaction with the cable itself, which provides – as well as structural damage – a potentially harmful heat source. The present study trains the possibility of evaluating different layouts, operating and boundary conditions, paving the way for a more and more realistic design approach.