Micro structure and oxidation behavior of Zr-Nb alloy for fuel cladding material of nuclear power plant

Synthesis of zirconium alloy Zr-Nb was performed to develop the zirconium alloy as a candidate of ATF (Accident Tolerant Fuel) cladding material. The synthesis was carried out with composition of Zr-3Nb and Zr-6Nb (wt%) by the casting method using an arc melting furnace covered by argon gas. Microstructure characterization was performed by evaluate the morphology and identified the elemental composition completed with phase identification using the SEM-EDX and XRD test. The oxidation test was carried out by the thermo gravimetric test using the Magnetic Suspension Balance (MSB) equipment. Analysis of micro structure showed relatively the mix of lancette and equiaxed fine grain type with mainly consists of α-Zr phase and β-Zr phase. The oxidation test of Zr-3Nb and Zr-6Nb (wt%) alloys showed that the oxidation rate followed a parabolic type curve. Composition of Nb in the alloy affected significantly to the oxidation behavior through the oxide layer type formation.