Bi-Doped Zirconium Alloys with Enhanced Water Oxidation Resistance

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.