STP1125: Radiation-Induced Segregation in 20Cr/25Ni/Nb Stainless Steel

    Norris, DIR
    Nuclear Electric plc, Berkeley Nuclear Laboratories, Berkeley, Gloucestershire

    Baker, C
    Nuclear Electric plc, Berkeley Nuclear Laboratories, Berkeley, Gloucestershire

    Taylor, C
    AEA Technology, Northern Research Laboratories, Windscale, Cumbria

    Titchmarsh, JM
    AEA Technology, Harwell Laboratory, Oxfordshire

    Pages: 18    Published: Jan 1992


    Abstract

    Intergranular corrosion of irradiated austenitic steels has been attributed to compositional changes produced by radiation-induced segregation at grain boundaries, and the effect has been investigated for the 20Cr/25Ni/Nb stainless steel employed as fuel cladding in advanced gas-cooled reactors. Analytical electron microscopy has been used to determine compositional profiles at grain boundaries in irradiated samples.

    The observations are explained in terms of a model based on the inverse Kirkendall effect. At higher doses, interpretation is complicated by grain boundary migration, and compositional changes are found to persist after a boundary has moved away. The compositional profiles are compared with corrosion data for the same irradiated material. Results of Strauss corrosion tests are found to correlate with widths of chromium-depleted zones.

    Silicon segregation towards boundaries is a feature of the observations at the lower irradiation temperatures.

    Keywords:

    austenitic stainless steel, fuel cladding, grain boundaries, radiation-induced segregation, intergranular corrosion, analytical electron microscopy


    Paper ID: STP17898S

    Committee/Subcommittee: E10.08

    DOI: 10.1520/STP17898S


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