Experimental and Analytical Approaches on JT—60SA TF Strand and TF Conductor Quality Control During Qualification and Production Manufacture Stages

Abstract

In the framework of the JT-60SA project, aiming at upgrading the present JT-60U tokamak, Europe as part of its in-kind contribution within the Broader Approach agreement, will provide the full Toroidal Field (TF) magnet system. For this purpose, Fusion for Energy is committed to procure about 27 km of TF conductor. The TF conductor is cable-in-conduit type and includes 486 strands (2/3 NbTi-1/3 copper) wrapped with a thin stainless steel foil and embedded into a rectangular stainless steel jacket. The procurement is split into two main contracts: one for strand manufacturing and the other for cabling and jacketing. After having successfully passed the qualification stage, strand and conductor are now in mass production stage. In the present paper, we emphasize on the scientific and quality control approaches of both TF strand and TF conductor productions. For the NbTi strand, the focus is on design and measurement of performance critical aspects (CuNi barrier design optimization, AC losses, TCS performance, etc.). For Cu strand the main issue is RRR. For the TF conductor, the topics presented cover hydraulic correlation validation measurements (pressure drop tests), geometrical advanced controls, and electromagnetic behavior (hotspot checks and mainly the experimental results of the TF conductor full-size samples tested in SULTAN facility). The article presents comparisons of numerical simulation and experimental results used to confirm the design and the manufacturing processes.