STP1354

    Corrosion of Electron-Irradiated Zr-2.5Nb and Zircaloy-2

    Published: Jan 2000


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    Abstract

    We used 10-MeV electrons to rapidly produce radiation damage in zirconium alloys, investigated whether electrons produced the same microstructural changes as neutrons, then performed post-irradiation corrosion tests to determine whether electron-irradiated materials displayed similar corrosion behavior to neutron-irradiated materials.

    Two irradiations were completed using 10-MeV electrons with the beam normal to thin disks of material of a diameter slightly larger than the beam. The beam distribution and disk cooling were designed to produce radial temperature and dose distributions having maxima at the disk center. A high-temperature irradiation was performed on annealed Zr-2.5Nb disks, achieving a central dose of 1.3 dpa and at a central temperature of ≈450°C. After irradiation, the samples contained needle-like β-Nb precipitates in the α-Zr matrix similar to those produced by neutrons. A low-temperature irradiation was performed on half-moon disks of Zr-2.5Nb and Zircaloy-2 pressure tube materials at 310°C central temperature and 1.3-dpa central dose. Dislocation loops were observed, again similar to those produced in neutron-irradiated materials.

    Some of the high-temperature electron-irradiated disks were exposed to 300°C moist air (saturated with D2O), and in separate tests, high- and low-temperature irradiated disks were corroded in 300°C D2O (11.0 pD at room temperature) in an autoclave. Measurements of oxide thickness by Fourier Transform Infrared Reflectance (FTIR) spectroscopy showed that electron irradiation reduced the corrosion rate of Zr-2.5Nb compared with that of unirradiated material, as observed for neutron irradiation. For exposures to moist air and to D2O, the theoretical deuterium uptakes for the electron-irradiated materials were, respectively, about 4 times and 1.5 to 2 times those for the unirradiated materials. This is also in good agreement with results for neutron-irradiated pressure tube materials. Thus, 10-MeV electrons produced the same corrosion behavior as fast neutrons in post-irradiation corrosion tests of Zr-2.5Nb pressure tube materials. For Zircaloy-2, the corrosion rates were the same for both electron-irradiated and unirradiated materials, similar to those observed for neutron-irradiated Zircaloy-4.

    Keywords:

    Zr-2.5Nb, Zircaloy-2, electron irradiation, neutron irradiation, microstructures, corrosion, deuterium uptake, intermetallic particles, dislocation loops


    Author Information:

    Woo, OT
    Scientists, AECL, Chalk River Laboratories, Chalk River, Ontario

    McDougall, GM
    Scientists, AECL, Chalk River Laboratories, Chalk River, Ontario

    Hutcheon, RM
    Scientists, AECL, Chalk River Laboratories, Chalk River, Ontario

    Urbanic, VF
    Manager, AECL, Chalk River Laboratories, Chalk River, Ontario

    Griffiths, M
    Scientists, AECL, Chalk River Laboratories, Chalk River, Ontario

    Coleman, CE
    Manager, AECL, Chalk River Laboratories, Chalk River, Ontario


    Paper ID: STP14324S

    Committee/Subcommittee: B10.02

    DOI: 10.1520/STP14324S


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