Electromagnetic modeling for JT-60SA divertor HHF OVT C target

Abstract

The JT-60SA tokamak is being developed with the aim of supporting the activities for the ITER project, as well as towards the realisation of DEMO. In this framework, a joint study between Fusion for Energy (F4E) and CEA has been established via EUROfusion to assess the behaviour of the High Heat Flux actively cooled Carbon target of the JT-60SA divertor. Specifically, this paper is dedicated to present the methods and results of electromagnetic (EM) and relative Transient Structural (TS) analyses for determining the loads due to Eddy Currents in case of representative plasma disruptions.As first EM calculations for this component, and with a small analysed target, the type of carried out calculation is a 3D transient, local EM analysis by means of Ansys Maxwell code. The used local EM analysis technique allows to analyse the behaviour of isolated components subjected to a uniform magnetic field. This method has been benchmarked and it has already been successfully used in other applications for Fusion community. It is a simplified method, not suitable to calculate net forces, but still presents some undeniable advantages. Moreover, the obtained results have been compared to the ones of a global model.As far as the analysis inputs are concerned, the magnetic data during the disruption have been provided by F4E for two different scenarios (a downward Major Disruption and a Vertical Displacement Event). The input is a space-uniform, time-varying magnetic field from the EM analysis of the JT-60SA sector.After running the Maxwell calculations, the obtained results have been provided as input to the corresponding TS calculations (carried out using Ansys Workbench) to assess acceptability of the loads. These last analyses have demonstrated that EM loads are not design driving loads for the component and that the simplified method provides conservative results.