SEM characterization of two advanced fuel alloys: U-10Zr-4.3Sn and U-10Zr-4.3Sn-4.7Ln

Tin is being investigated as a potential additive to metallic fuel to control fuel-cladding chemical interaction (FCCI). A primary cause of FCCI is the lanthanide fission products moving to the fuel periphery and interacting with the cladding. This interaction will lead to wastage of the cladding and eventually to a cladding breach. The current study is a scanning electron microscopy (SEM) characterization of as-cast and annealed U-10Zr-4.3Sn and U-10Zr-4.3Sn-4.7Ln, where Ln = 53Nd-25Ce-16Pr-6La. The present study shows that tin preferentially binds the lanthanides, which will prevent lanthanide migration and interaction with the cladding.