Understanding and optimizing the performance of NbTi and Nb3Sb based Cable-In-Conduit Conductors for application in Magnets for Fusion

by Gabriella Rolando (University of Twente, The Netherlands)

Tuesday 19 Feb 2013, 14:00 → 15:00 Europe/Zurich

30/7-018 - Kjell Johnsen Auditorium (CERN)

Abstract: Making a high current Cable-In-Conduit Conductor (CICC) is much more than just intuitively packing several hundreds of strands in a jacket. The strand and cabling parameters must be carefully chosen since they can seriously affect the performance of the final magnet. In the framework of the ITER conductor development program extensive effort has been spent to understand and optimize the conductors. Given the high cost and time consumption of the test of conductor samples, simulation is an essential tool to predict cable performance. However, correct modeling of CICCs is complicated due to the nature of the conductor assembly, where up to more than 1000 coated strands are twisted and compacted in multiple cabling stages also incorporating cooling channels and sub-cable wraps. As a consequence, strands follow entangled trajectories inside the conductors, resulting in a complex network of contacts whose effective behavior is determined by the strand properties and cabling pitches. This largely affects the steady-state and ramped operations of the conductor in terms of current non-uniformity, coupling loss and temperature margin. The new numerical model JackPot-ACDC for the electro-magnetic simulation of CICCs is introduced. The model is applied to assess in particular the performance of various full-size conductors and joints envisaged for the International Thermonuclear Experimental Reactor (ITER) under both test and operating conditions. Examples of the output of such analysis and their relevance for the design of the ITER conductors are illustrated.

Slides CERN_19_02_2013_v3.pdf