Engineering design and analysis of first wall on the high-magnetic-field-side for HL-2M tokamak

Abstract

The first wall is one of the key in-vessel components, which would be employed for protecting the vacuum vessel and other in-vessel components (e.g. diagnostic components, gas injection system, resonant magnetic perturbation coils). The first wall is facing the high temperature plasma, and the graphite is adopted as plasma facing material for HL-2M tokamak due to its many excellent properties including high thermal conductivity, good thermal shock, thermal fatigue resistance and good compatibility with plasma. The first wall on the high-magnetic-field-side is consisted of the graphite tile, the back plate, supports and the adjustment plate, and no active cooling structure is considered except for the residual neutral beam power region. All of the first wall parts are assembled with different bolts, and they are easy to install and maintain during their running life. All of the analysis results based on the finite element method show that the structural design of the first wall on the high-magnetic-field-side has good heat transfer performance, satisfying the thermal design requirements during the plasma operation stage (the average value of heat load in the residual neutral beam power 1.0 MW/m2, thermal load in other region 0.3 MW/m2, pulse time 5 s) for HL-2M device. The first wall can also withstand the impact of the electromagnetic load caused by 1.8 MA plasma disruption, including the major disruption and the vertical displacement events.