Operational Capability Evaluation Of EAST Tungsten-Copper Divertors Under EM Loads In VDEs

As the first full superconducting tokamak device, EAST has achieved IMA plasma current, long pulse discharge of 400 seconds for the first time, stable and repeatable high constraint patterns plasma discharge of more than 30 seconds, which makes it very important to researching high temperature plasma and the operation of ITER. Because of complicated electromagnetic field and thermal environment, invessel components will not only suffer high thermal loads from plasma, but also suffer huge and complicated thermal stress and electromagnetic loads. Currently, all kinds of failure patterns including fracture, ablation, exfoliation, flabby, plastic deformation have been observed in graphite tiles, heatsinks, cooling water pipes and support components of EAST, and the divcrtor is the most vulnerable due to its working condition. The inner plates and outer plates of EAST upper divertor module have chosen the mono-block structure as cooling structures, and because of the gap between tungsten blocks, eddy current induced in CQ and VDEs is greatly reduced. The maximum halo current can reach 50 percent of plasma current, which will cause huge EM impact on divertor components. Aiming at researching the effect of EM impact on divertor components, the following three aspects of work has been done in this paper. Firstly, dynamical experiments on W, TZM and CuZrCr employed in EAST tungsten divertors were performed using a Kolsky bar system. And constitutive equations involving five material constants were built by using Johnson-Cook model to describe the dynamical properties of these three materials. Secondly, according to three halo configurations of vertical displacement events on 1TER, halo current distributions on EAST divertor module were calculated. By importing the current results, the electromagnetic loads and statics analysis were calculated. According to the results of static structural analysis, the strength of the divertor components was evaluated. Finally, by using the calculation of electromagnetic load and its variation law with time, dynamical analysis on mono-block structure of the inner plates was performed, and strength analysis and life prediction were done to evaluate effects on divertors under EM impact.