抄録
Oxidation behavior of the stainless steel for a fast breeder reactor fuel cladding was studied in the temperature range of 8731, 073 K. The oxygen pressure in the fuel-cladding gap was simulated by the Mo/MoO2 or the NbO2/Nb2O5 oxygen buffer. The oxidation kinetics was found to obey the parabolic rate law. The temperature dependence of the parabolic rate constants is given by the following equations : Under the oxygen pressure controlled by the NbO2/Nb2O5 oxygen buffer (po2=1.6×10-25 Pa),
kp(T)=6.50×10-8exp(-99.0×103/RT).
Under the oxygen pressure controlled by the Mo/MoO2 oxygen buffer (po2=1.9×10-21Pa),
kp(T)=4.75×10-7exp(-99.6×103/RT).
where kp and the activation energy are expressed in terms of kg2/m4•s and J/mol, respectively. The oxidation mechanism was discussed on the basis of the metallographical information and the value of activation energy of the parabolic rate constant.
