Preliminary Design of DC Magnet for Super-X Test Facility

The engineering design of the China Fusion Engineering Test Reactor (CFETR) has been completed in 2020. A largescale RD project for CFETR named the comprehensive research facility for fusion technology (CRAFT) was initiated in Sep. 2019. As a sub-task of the CRAFT, a superconducting experiment testing platform (Super-X for short) is planned to be constructed for evaluating the future superconducting parts performance. Its main technical parameter includes: the background field of 15 T, the dimensions of testing space of 100 × 160 × 550 mm, the field homogeneity of testing space ≥ 95%, and the maximum testing current of 100 kA. For now, the preliminary design for Super-X has been accomplished. The DC magnet provides the background magnetic field for Super-X. It is a kind of split coil that includes two symmetrical coils assemblies. The innermost diameter is about 644 mm, the outermost diameter is 2874 mm. Each coil assembly is composed of three concentric Nb3Sn coils. The peak field is 15.7 T and the field homogeneity reach to 98.2%. The high field coil (HFC) and medium field coil (MFC) is typically dominated by high-Jc Nb3Sn cable-in-conduit conductor (CICC), and the low field coil (LFC) by ITER grade Nb3Sn CICC. This paper presents the preliminary design of the background DC magnet system (BM).