Effect of Zr Thin Film on Zr Foil as a FCCI Barrier Between Lanthanide (La-Ce) and Clad Material

Abstract

Zirconium (Zr), a potential candidate for preventing Fuel-Cladding Chemical Interaction, shows stable interdiffusion behavior between cladding and fuel materials. However, a 25 mu m-thick Zr foil allows local inter-diffusion, due to defects generated during manufacturing. In this study, we investigate the use of a Zr thin film deposited on Zr foil for preventing local inter-diffusion. The diffusion behavior of the Zr thin film on Zr foil was investigated using misch metal (Ce: 75% and La: 25%) as fuel fission product, in order to effectively simulate nuclear fuel. While without the Zr barrier substantial inter-diffusion occurred at the interface between the ferritic/martensitic HT9 cladding material and misch metal, the Zr thin film on Zr foil exhibited excellent resistance to interdiffusion. The enhancement of the barrier ability of the Zr thin film on Zr foil was attributed to a lower amount of defects induced by the Zr thin film layer.