International Congress on Advanced Nuclear Power Plants in Hollywood, Florida, June 9-13, 2002 Design and Analysis for Melt Casting Metallic Fuel Pins Xiaolong Wu, Randy Clarksean, and Yitung Chen Department of Mechanical Engineering University of Nevada, Las Vegas and Mitchell K. Meyer Nuclear Technology Division Argonne National Laboratory, Idaho Falls, ID Abstract A concept for the casting of metallic fuels pins containing low vapor pressure materials is presented and discussed. The important physics of this concept include the mass transport of americium from the melt, the induction heating and stirring of the melt, plus the casting of long slender fuel rods. This paper discusses and presents preliminary modeling results for the casting of long, slender fuel rods. The model considers the flow of the melt into the molds, heat transfer into the molds, and the impact of process parameters on the formation of the fuel rod. Background The United States is embarking on a national program to develop accelerator transmutation of high-level radioactive waste (ATW) as part of the Advanced Accelerator Applications (AAA) project at its national laboratories. Through the AAA Program, the U.S. joins international efforts to evaluate the potential of partitioning and transmutation along with advanced nuclear fuel cycles. Transmutation means nuclear transformation that changes the contents of the nucleus (protons and/or neutrons). The research and development efforts will consider a coupled accelerator and sub- critical multiplying assembly, explore the transmutation of waste from used nuclear fuel, testing of advanced nuclear fuels, and the production of isotopes that may be required for national security and commercial applications. The AAA program has listed several critical issues in fuel requirements: cladding integrity, fission product retention, and dimensional, chemical, and metallurgical stability during irradiation under both normal and off-normal conditions. One of the potential fuel types is a metallic fuel, which is being developed by Argonne National Laboratory. An important aspect of this program is the development of a casting process by which volatile actinide elements (i.e., americium) can be easily incorporated into metallic fuel pins. The process relies on a traditional casting process using induction heating and quartz glass rods as molds. This process works well for the fabrication of metal fuel pins traditionally composed of alloys of uranium and plutonium, but does not work well when highly volatile actinides are included in the melt. Previous experience with this process indicates that there is the potential for large losses of americium. The present process relies on a vacuum casting procedure that is briefly overviewed here. The process relies on the use of quartz glass molds: straw-like tubes with one end closed. Quartz glass is used because it will not soften or distort when filled with molten metallic fuel. The feed-stock, which