Abstract Scope |
To improve the safety and lifetime of boiling water-type nuclear fission reactors, new accident tolerant fuels are under development where a Cr-alloy coating is applied to the conventional Zr-alloy nuclear fuel cladding. However, an undesirable brittle intermetallic layer of ZrCr2 may form between the Cr-based coating and the Zr-based alloy, damaging the integrity of the fuel system. Furthermore, diffusion of chromium, zirconium, and other alloying elements occurs in each of the metallic layers, affecting the alloy properties. The thermodynamics of the various interfaces and layers formed are considered using first-principles calculations to predict atomic migration and intermetallic phase formation within the system. Based on this data, candidate alloying elements for the Cr-alloy or Zr-alloy are proposed that may reduce the formation of the ZrCr2 intermetallic phases, eliminate significant volume changes that may cause microcracking, or that may improve the properties of the cladding system as a whole. |