The IGNITOR Load Assembly Structural Analysis and Toroidal Field Coil
The structural analysis of the IGNITOR machine load assembly has been performed taking into account the friction coefficients at the interfaces between the significant components. The finite element ANSYS model was used to analyze the nonlinear mechanical behavior of the structure. The calculation shows stresses within the allowable limits at the operating temperature. Interlaminar shear stresses values on TFC insulation have been validated by the results of test performed by Ansaldo. Two full size of Ignitor TFC turns have been manufactured by Kabel Metal to qualify the fabrication process and the hardening of the material OFHC. Several samples of the cooling channel were machined to validate the Electron Beam (EB) welding process
Optimization of the IGNITOR operating scenario at 11 MA
Abstract Several endeavours have been made, in the frame of the IGNITOR design, in order to minimize technological problems, reducing electromagnetic loads, power supply requirements while avoiding the use of not completely proven materials. The present design modifications comprise both the operating scenario for the poloidal field (PF) currents and the PF coils geometry. The new scenario and a relevant simulation of a related typical fast vertical disruption, in the most dangerous plasma conditions in IGNITOR, have been simulated with the MAXFEA code. In order to reduce the EM loads on plasma chamber and the related stresses due to plasma disruptions, a new approach has been investigated based on the possibility of mitigating these loads by using copper toroidal layers added to the plasma chamber in proper positions. We found that this expedient could be quite effective not only in increasing the time constant of the plasma displacement but even in reducing the vertical force and its combined effect with hoop force on the vessel during a vertical displacement event (VDE).
Ignitor plasma chamber structural design with dynamic loads due to plasma disruption event
Abstract During a plasma disruption in Ignitor [B. Coppi, IGNITOR Project Group, Engineering Design Description, Ignitor Programme, RLE Report no. PTP 96/03, December 1996], the electromagnetic (EM) loads are so large to require a dynamic elastic–plastic structural analysis of the plasma chamber (PC). A 30° sector of PC has been modeled. Static, dynamic and low cycle fatigue analyses under eddy and halo currents have been performed. It is shown that a PC wall thickness optimization limits the displacements within the clearance with toroidal coil. The fatigue lifetime is longer than the number of disruption events at the maximum performance.