High-temperature oxidation kinetics of sponge-based E110 cladding alloy

• Published in: Journal of nuclear materials Vol. 499; no. C; pp. 595 - 612
• Main Authors: Yan, Yong, Garrison, Benton E., Howell, Mike, Bell, Gary L.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.02.2018; Elsevier BV; Elsevier
• Subjects: Cladding; Correlation analysis; High temperature; Hydrogen; Kinetics; MATERIALS SCIENCE; Mathematical analysis; Mathematical models; Oxidation; Oxidation rate; Oxygen; Rate constants; Reaction kinetics; Steam; Studies; Thickness measurement; Weight gain measurement; Zircaloys (trademark); Zirconium base alloys
• ISSN: 0022-3115; 1873-4820
• DOI: 10.1016/j.jnucmat.2017.10.067

Two-sided oxidation experiments were recently conducted at 900°C–1200 °C in flowing steam with samples of sponge-based Zr-1Nb alloy E110. Although the old electrolytic E110 tubing exhibited a high degree of susceptibility to nodular corrosion and experienced breakaway oxidation rates in a relatively short time, the new sponge-based E110 demonstrated steam oxidation behavior comparable to Zircaloy-4. Sample weight gain and oxide layer thickness measurements were performed on oxidized E110 specimens and compared to oxygen pickup and oxide layer thickness calculations using the Cathcart-Pawel correlation. Our study shows that the sponge-based E110 follows the parabolic law at temperatures above 1015 °C. At or below 1015 °C, the oxidation rate was very low when compared to Zircaloy-4 and can be represented by a cubic expression. No breakaway oxidation was observed at 1000 °C for oxidation times up to 10,000 s. Arrhenius expressions are given to describe the parabolic rate constants at temperatures above 1015 °C and cubic rate constants are provided for temperatures below 1015 °C. The weight gains calculated by our equations are in excellent agreement with the measured sample weight gains at all test temperatures. In addition to the as-fabricated E110 cladding sample, prehydrided E110 cladding with hydrogen concentrations in the 100–150 wppm range was also investigated. The effect of hydrogen content on sponge-based E110 oxidation kinetics was minimal. No significant difference was found between as-fabricated and hydrided samples with regard to oxygen pickup and oxide layer thickness for hydrogen contents below 150 wppm.