Bi-Doped Zirconium Alloys with Enhanced Water Oxidation Resistance

Abstract

Zirconium (Zr) based cladding materials are widely used in commercial nuclear reactors, and it is essential to protect them from water oxidation to avoid serious safety issues in nuclear power plants such as those which occurred during the Fukushima nuclear accident. To provide guidelines to design novel Zr alloys with enhanced water oxidation resistance, we performed a first-principles high-throughput screening (HTS) search that is based on the water dissociation mechanism over the Zr basal plane. We apply this HTS approach to 53 metal dopants, including transition and nontransition metals, to single out the promising dopants in Zr−X binary alloys with significantly improved resistance of water oxidation. First, the adsorption and dissociation properties of water molecule on zirconium basal (0001) surface are determined using the density functional theory (DFT) calculations. Then the water dissociation barrier is used as a descriptor for the HTS screening. Next, the neutron cross-section is considered as the second criterion for the engineering applications of Zr−X alloys in nuclear reactions. Finally, the stability is checked for the possibility of processing these binary Zr−X alloys experimentally. According to this study, eight elements Al, Zn, Ge, As, Sn, Sb, Pb, and Bi are screened out as promising dopants to enhance the water oxidation resistance of Zr based cladding materials. Particularly, the Bi-doped Zr alloys exhibit excellent water oxidation by improving the reaction barrier to ∼215% compared to pure Zr.