Real-time fluid flow model for control of solidification

The Atomic Vapor Laser Isotope Separation (AVLIS) process is an advanced uranium enrichment technology being developed by the Lawrence Livermore National Laboratory. This process is designed to increase the concentration of /sup 235/U in uranium from 0.7%, as found in nature, to approximately 3%, as required for light water nuclear reactor fuel. Separation is accomplished by vaporizing Uranium, selectively ionizing /sup 235/U atoms and electromagnetically collecting these ions. The electromagnetic collector system uses resistance heaters to maintain a temperature range defined by the melting point of the metal product and tails collected and the materials compatibility limits between the liquid metal and the structure. If temperatures are not within these bounds, metal freezing or structural damage, both of which disrupt the process, may occur. Additionally, inappropriate heater usage could result in heater burn-out or overheating. The authors have developed a real-time decision support model for control of the heaters and to predict mass flow and accumulation of product