Current Centre Line Control, Results and Comparison After the Manufacturing of the ITER Toroidal Field Coils

In 2021, seven Toroidal Field Coil (TF) are already built by European industries and delivered to the ITER Organization (IO). The TF are composed mainly by a superconducting Winding Pack (WP), and the enclosing Coil Cases (TFCC). One of the main parameters characterizing the TFCs is the Current Centre Line, defined as the barycentre of the WP conductors. The CCL has been initially calculated for all the TFCs, and Fusion for Energy (F4E) developed a methodology to monitor and control the CCL during the subsequent manufacturing processes, including WP insertion, TFCC welding, preparation for machining and final measurements. The method is based on detailed laser measurements, CAE models and data processing, and it provides one of the main inputs to be considered when defining the final machining of the component. The final CCL position after machining can be further used as input parameter during the machine assembly and it is useful to understand important aspects for the operation of ITER reactor such as the Error Field. This paper presents the results of the abovementioned strategy for the coils completed so far, during the different manufacturing phases, and the intermediate results of the remaining coils under construction. It focuses on the similarities and differences obtained comparing the TFs, and it assesses the correspondence of the CCL data with other parameters related to the magnet.