Hydrogen ingress into oxidized Zr-2.5Nb

• Published in: Journal of nuclear materials 1994-03, Vol.209 (1), p.52-61
• Main Authors: Laursen, T., Palmer, G.R., Haysom, J.E., Nolan, J., Tapping, R.L.
• Format: Article
• Language: English
• Subjects: Applied sciences; Energy; Energy. Thermal use of fuels; Exact sciences and technology; Fission nuclear power plants; Installations for energy generation and conversion: thermal and electrical energy
• ISSN: 0022-3115; 1873-4820
• DOI: 10.1016/0022-3115(94)90247-X

Deuterium (D) distributions in D 2O-corroded Zr-2.5 wt% Nb samples have been measured for three different corrosion temperatures: 763, 673 and 573 K. The oxide thickness and details in the D profile for 763 K show considerable variation due to changes in surface preparation. Nevertheless, the D concentration in the central part of the oxide is within 0.002−0.005 D Zr atomic ratio. At lower temperatures − 673 K and below — the D concentration is somewhat higher: ∼ 0.01 D Zr . These concentrations are less than the 2–5% level observed with Zircaloy-2 after corrosion at 763 K. D distributions in O 2-oxidized Zr-2.5 wt% Nb have been measured following a subsequent exposure to either D 2 or D 2O exposure at 573 K. D ingress into the metal is enhanced with D 2 compared to D 2O, supporting the expectation that reducing conditions (D 2) may lead to a degradation of the protective oxide. Evidence is presented that two different diffusing species are responsible for the different D distributions measured in the oxide for the two types of exposure.