A study was made of the oxidation kinetics and oxygen diffusion coefficients of low-Sn Zircaloy-4 at 973 to 1123K, and at above 1373K. Two different cases were considered: dissolution of a pre-existing oxide layer at 973 to 1123K, and oxidation at >1373K. The oxygen diffusion coefficient in the αZr phase at 973 to 1123K could be expressed as:

D(cm2/s) = 6.798 x 100exp[-217.99(kJ/mol)/RT]

At 1373 to 1523K, the oxygen diffusion coefficients in αZr and βZr were determined by using the so-called inverse identification method. They could be expressed as:

Dα (cm2/s) = 1.543 x 100exp[-201.55(kJ/mol)/RT]

Dβ (cm2/s) = 6.8 x 10-3exp[-102.62(kJ/mol)/RT)

Finally the oxygen diffusion coefficient in αZr at 973 to 1523K was determined, by combining all of the results:

Dα (cm2/s) = 4.604 x 100exp[-214.44(kJ/mol)/RT]

X.Ma, C.Toffolon-Masclet, T.Guilbert, D.Hamon, J.C.Brachet: Journal of Nuclear Materials, 2008, 377[2], 359-69