STP824: High-Fluence Irradiation Growth of Zirconium Alloys at 644 to 725 K

    Tucker, RP
    Principal engineer and manager, Core Materials Testing and Analysis, General Electric Co., Vallecitos Nuclear Center, Pleasanton, Calif.

    Fidleris, V
    Senior research officer, Atomic Energy of Canada Ltd., Research Co., Chalk River Nuclear Laboratories, Chalk River, Ont.

    Adamson, RB
    Principal engineer and manager, Core Materials Testing and Analysis, General Electric Co., Vallecitos Nuclear Center, Pleasanton, Calif.

    Pages: 23    Published: Jan 1984


    Abstract

    Irradiation growth behavior of zirconium, Zircaloy-2 and Zircaloy-4,Zr-2.5Nb, and Zr-3.5Sn-0.8Mo-0.8Nb (EXCEL) was studied on specimens irradiated in the Experimental Breeder Reactor II (EBR-II) to fluences of 1.2 to 16.9 × 1025 neutrons (n)·m−2 (E > 1 MeV) in the temperature range 644 to 725 K. In Zircaloy, growth and growth rate were observed to increase continuously with fluence up to 16.9 × 1025 n·m−2 with no indication of saturation in either recrystallized or cold-worked materials. Positive growth strains of 1.5% and negative strains of approximately 2% to 2.5% were observed in both recrystallized and cold-worked Zircaloy. The formation of both a-type loops and c component dislocations is recrystallized Zircaloy under irradiation appears to be the basis in this material for growth strains similar in magnitude to those in cold-worked Zircaloy. Alloy additions to zirconium can increase growth by as much as an order of magnitude for a given texture at the higher irradiation temperatures and fluences. A sharp change to increasing growth rate with temperature occurs in Zircaloy at ∼670 K, with a similar trend indicated for the other alloys. Although growth in all these alloys is a strong function of crystallographic texture, an exact (1–3f) type of dependence is not always apparent. In Zr-2.5Nb the dependence of growth on texture appears to be masked by the precipitation of betaniobium, with a transition to a well-defined texture dependence being a function of fluence and temperature. Significant differences in growth behavior were observed in nominally similar Zircaloys, apparently due to minor microstructural or chemical differences.

    Keywords:

    zirconium, zirconium alloys, nuclear industry, irradiation growth, recrystallized, cold-worked, neutron irradiation, temperature, fluence, texture, microstructure, dislocations, volume change


    Paper ID: STP34484S

    Committee/Subcommittee: B10.02

    DOI: 10.1520/STP34484S


    CrossRef ASTM International is a member of CrossRef.