The occurrence of porosity during alloy solidification is a significant factor in evaluating the quality of metal castings. In general, porosity forms when there is solidification shrinkage, failure of interdendritic feeding or exsolution of dissolved gas from the melt. The existence of porosity in castings is known to negatively effect mechanical properties, such as tensile strength, and fatigue life [1–4]. Foundry process computer simulations that help determine the location, size, shape and extent of porosity can be used by the casting designer to evaluate the probability of detecting porosity by NDE techniques.