Numerical assessment of thermal performance of W/Cu monoblock during steady-state operation and plasma vertical displacement events under ITER-like conditions

This paper employs a two-dimensional conduction model to assess the spatiotemporally thermal performance of ITER W/Cu monoblock under ITER-like conditions. The model considers the heat conduction processes including the evaporation, radiation and melting of both W armor and Cu heat sink materials under a heat load either during steady-state discharge or during plasma vertical displacement event (VDE). Moreover, the model employs coupling cooling water condition instead of the fixed cooling temperature at bottom in authors' previous work. For the steady-state case, the heat flux distribution on the target tile, the input data to the model, was specifically evaluated by a particle-in-cell code to take into account its geometrical effect. For the VDE case, the heat flux distribution was simply assumed to be uniform on the tile surface. The simulated results obtained from the heat conduction model indicate that cooling water conditions have important influence on the thermal performance of W/Cu monoblock, especially for Cu heat sink materials during steady state. In the case of VDE, the baffle tile surface would undergo intense vaporization and melting, while whether Cu heat sink materials melted was determined by the combination of the exposed heat load and its duration. Based on typical VDE heat loads, detailed analysis is presented herein. PACS: 52.55.Fa, 52.55.Rk, 52.40.Hf, 52.65.-y