The scaling parameterization of ITER superconducting Nb-Ti strands throughout worldwide production

The ITER superconducting magnet system will require approximately 650 tons of toroidal field and central solenoid Nb3Sn strands with different designs, and more than 250 tons of Nb-Ti strands. This called for a significant scale up of the worldwide production of Nb3Sn and Nb-Ti strands. Over the worldwide and mass productions, it is essential to accurately analyze and characterize the properties of ITER superconducting strands in terms of critical current (Ic) and ac loss, and thus determine the operational limits of the conductors, ultimately optimizing the operating scenarios of the Tokamak. In this paper, the proper scaling parametrization Ic(B, T) and n-value as a function of Ic (n(Ic)) are investigated for Nb-Ti strands throughout massive production. Despite the differences in ITER Nb-Ti strand's architecture and their composition, optimized Nb-Ti strand scaling parameterizations throughout production for each supplier have been reached with the minimal deviation (<;15%) for all the measured data in a wide B, T window and even <;5% in the operation condition region. This is to be applied for the analysis of the Nb-Ti conductors made from these stands and to assess possible evolution over production.