1P.Testoni, 1F.Cau, 1A. Fanni, 1M. Di Mauro, 2A. Portone, 2E.Salpietro, 3P.Sonato

1
Engineering design of the European
Superconducting Dipole
1P.Testoni, 1F.Cau, 1A. Fanni, 1M. Di Mauro, 2A.
Portone, 2E.Salpietro, 3P.Sonato
1DIEE, University of Cagliari, 2 EFDA, Garching,
3 Consorzio RFX
Introduction

• The design of a high-field superconducting dipole
  magnet is in progress in order to make available
  a new facility to perform tests of large
  superconducting conductors in high magnetic
  fields (B12.5 T)
• The main use of the facility shall be to test
  the ITER conductors during the manufacturing of
  the ITER magnets in order to implement the
  quality control program
• 2D and 3D Finite Element Models of the dipole
  have been built and several electromagnetic and
  thermo-mechanical analyses have been performed
  with the ANSYS code in order to study, optimize
  and verify the requirements of the system

Fig.1 Dipole section
Model description

• The dipole magnet consists of a pair of identical
  saddle-shaped coils having a rectangular cross
  section
• The coils are layer wound using a Cable in
  Conduit Conductor (CICC) made of Nb3Sn strands
  jacketed inside a high strength, austenitic steel
  conduit
• A circular shaped iron yoke is used to improve
  the field quality and intensity over the bore
  cross-section
• An outer steel cylinder made of austenitic steel
  encloses the entire dipole assembly and provides
  pre-compression at cryogenic temperature due to
  the differential thermal contraction
• Each coil is made of a High Field (HF) section
  and a Low Field (LF) section. In each coil, the
  HF section is made of two double layers and the
  LF section is made of five double layers
• Due to symmetry, only a quarter of the dipole
  section has been considered in the 2D model
• Only an eight of the dipole and winding pack
  smeared properties considered in the 3D model

Fig.2 3D Model
Fig.4 2D Model of the winding pack
Fig.3 2D Model
Fig.5 2D Detail of a conductor

• Electromagnetic Analysis
• 17kA in each turn to have a B field of 12.5 T in
  the bore
• Edge, MVP and MSP formulations compared
• Stored magnetic energy, field distribution
  computed

• Thermo-Mechanical Analysis
• EM and structural models share the same mesh, in
  order to transfer the loads without approximation
  and/or interpolation
• Loads Lorentz forces, Magnetic forces in
  ferromagnetic
• materials, thermal gradient form
  433 K to 4 K
• Contact elements between components
• Comparison between 2D generalized plain strain,
  plain
• stress and plain strain formulations
• Quadratic elements used in 3D analysis

Fig.7 Magnetic field in the 3D analysis
Fig.6 Magnetic field in the 2D analysis
Conclusions
Fig.8 Stress intensity in the jacket
Fig.9 Stress intensity in the iron
Results obtained have shown the feasibility and
reliability of the system favouring its
optimisation respect to the electromagnetic and
mechanical criteria