Stability analysis of ITER Poloidal Field Coils conductors

The stability analysis [1] of the Poloidal Field Coils of the ITER Project, specially the PF5, PF3 and PF2 coils for scenario #2, normal mode has been performed using the Gandalf [2] code. The conductor stability is assessed in the most severe operating conditions, at the minimal temperature margin time of the 4th pulse. It consists in determining the maximal deposited energy (perturbation in mJ/cm3 of superconducting strands) which can be absorbed without runaway. This study is performed for three initial different designs: Cu–nonCu ratio of 2.3, 1.6 and 4.4 for PF5, and Cu–nonCu ratio of 2.3, 1.6 and 6.9 for PF3 and PF2. The results are presented as well as a discussion about the phenomena, important parameters and uncertainties. For each type of perturbation, the calculated stability limits are quite similar from one design to another. The low Cu–nonCu ratios do not show significant stability degradation compared to the original ITER design with high ratios.