Metal Fuel-Cladding Interaction

In the past few years, more work has been performed investigating FCCI. Some work has focused on characterizing previously-irradiated Experimental Breeder Reactor-II (EBR-II) or Fast Flux Test Facility (FFTF) fuel elements, which resulted in the generation of new data on how interaction zones develop at the fuel/cladding interface as a function of different irradiation conditions. Other work has been reported for out-of-pile diffusion couple experiments that were conducted to develop better understanding of how U-based alloys and fission products interact with cladding constituents. This included work that looked at ways to mitigate FCCI through use of alloying constituents to the fuel that could be added to influence the migration of fuel constituents to the fuel/cladding interface. The goal of the additions was to ‘tie up’ fission products in the fuel so that they would not participate in any interaction between the fuel and cladding. Since ultimately it is of interest to eliminate FCCI all together, there has been significant research looking at different materials that could be applied to the inner surface of the cladding to serve as a diffusion barrier. Computer modeling has also been focused on modeling FCCI behavior in irradiated metallic nuclear fuel. This goal of this book chapter is to discuss the FCCI research that has most recently been performed, including the major findings from this work.