Toroidal Field Model Coil geometry survey

The Toroidal Field Model Coil (TFMC) is a 36 tons "race-track" shaped coil about 4 m high and 3 m wide scaled with respect to the full-size ITER TF coils and including the key technical features and manufacturing approaches foreseen for the actual ITER TF coils. The objective of the TFMC Project is to develop and demonstrate the superconducting magnet technology to a level that will allow the ITER TF coils to be built with confidence. The TFMC has been installed in the TOSKA facility (Forschunszentrum Karlsruhe, Germany) after assembling the TFMC into a 27 tons stainless steel Intercoil Structure which interfaces the TFMC to the TOSKA facility. Due to the complexity of the assembly operations, and in order to avoid any trial-and-error assembly process with the associated loss of time and waste of resources, computer simulations have been extensively used. Additionally, starting from 3D CATIA models, a laser tracking technique has been utilized to retrieve as built geometry data of each sub assembly. The raw data have been analyzed and combined to verify the assembly procedure and to identify corrective actions before the real installation. The whole survey has been accomplished by ENEA during three different survey campaigns carried out at Alstom (Belfort, France) and at Forschungszentrum Karlsruhe (FZK, Karlsruhe, Germany) sites. The implementation of the data resulted in the TFMC being installed with no loss of time due to modifications to components previously measured and analyzed by the method reported here. This paper illustrates the geometry survey, the method and the instrumentation adopted and the results obtained. Moreover, it gives guidelines to the designer to be taken into account in the assembly planning of large and heavy components.