Status of LMR fuel development in the United States of America

Three fuel systems oxide, metal, and carbide are shown to be reliable to high burnup and a fourth system, nitride, is shown to have promise for LMR applications. The excellent steady state performance of the oxide and metal driver fuels for FFTF and EBR-II, respectively, supported by the experience base of tens of thousands of test pins is provided. Achieving 300 MWd/kg in the oxide fuel system through the use of low swelling cladding and duct materials and the Integral Fast Reactor (IFR) concept that utilizes metallic fuel are described. Arguments for economic viability are presented. Responses to operational transients and severe over-power events are shown to have large safety margins and run-beyond-claddingbreach (RBCB), is shown to be non-threatening to LMR reactor systems. Results from a joint U.S.-Swiss carbide test that operated successfully at high power and burnup in FFTF are also presented.