A transient concrete ablation/decomposition model was derived based on an integral analysis technique for conduction into and decomposition and ablation of the concrete. The resultant model predictions were then compared to concrete erosion data from well-defined “separate effect” tests and found to be in good agreement, when the assumed polynomial temperature profile was assumed to be quadratic. The model does not properly account for the details of the in-depth evaporable water saturation zone, since it only models the phenomena in an integral sense. This model is simple enough so that it can be incorporated into the larger molten-core/concrete interaction codes to predict concrete erosion rates.