Plasma disruptions infusion reactors lead to high-energy deposition for short periods of time, causing melting of the first wall. A two-dimensional transient computer model has been developed that, by solving the equations of motion and energy, predicts the depths and the motion of the molten layers in small beam simulation experiments. It is demonstrated that convective flows caused by variations of surface tension—due to changes in material chemistry and surface temperature—play an important role in determining the depth and flow intensities of the molten layers. The calculated shapes and depths of the molten layers for Type 316 stainless steel have been compared with available experimental results and found to be in good agreement.