STP1447

    Determination of the Lower Temperature Limit of Void Swelling of Stainless Steels at PWR-Relevant Displacement Rates

    Published: Jan 2004


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    Abstract

    Recent studies associated with light water reactors (LWR) in both the USA and Russia have raised the question of void swelling in austenitic components of core internals. One question of particular interest is the range of temperatures over which voids can develop, especially the lowest temperature. To address this question a flow restrictor component manufactured from annealed X18H9T was removed from the reflector region of the BN-350 fast reactor, located in Kazakhstan. During operation this component spanned temperatures and dpa rates of direct interest to pressurized water reactors (PWRs) in the West and VVERs in Russia. This steel is analogous to AISI 321 and is used in Russian reactors for applications where AISI 304 would be used in the West and in Japan.

    This component was sectioned on a very fine scale to determine in what range of conditions voids existed. Microstructural data were obtained for 157 separate locations, with 111 specimens showing voids over the relevant range of temperatures and displacement rates, allowing construction of a parametric map of swelling with temperature, dpa and dpa rate. These data show that swelling at doses as high as ∼50 dpa persists down to ∼306°C for dose rates in the range 0.11 × 10-7 to 1.6 × 10-7dpa/sec. Since the helium generation rate is rather low in the spectral environment of the flow restrictor, the early onset of swelling is attributed primarily to the lower displacement rate, a conclusion supported by a number of other experimental studies.

    Keywords:

    austenitic steels, voids, swelling, lower temperature limit, microstructural data, neutron irradiation, displacement rate


    Author Information:

    Porollo, SI
    Head of Laboratory, Principal Research Scientist, Head of Group, and Engineer, State Scientific Center of Russian Federation, Institute of Physics and Power Engineering (IPPE), Obninsk, Kaluga Region

    Konobeev, YV
    Head of Laboratory, Principal Research Scientist, Head of Group, and Engineer, State Scientific Center of Russian Federation, Institute of Physics and Power Engineering (IPPE), Obninsk, Kaluga Region

    Dvoriashin, AM
    Head of Laboratory, Principal Research Scientist, Head of Group, and Engineer, State Scientific Center of Russian Federation, Institute of Physics and Power Engineering (IPPE), Obninsk, Kaluga Region

    Krigan, VM
    Head of Laboratory, Principal Research Scientist, Head of Group, and Engineer, State Scientific Center of Russian Federation, Institute of Physics and Power Engineering (IPPE), Obninsk, Kaluga Region

    Garner, FA
    Laboratory Fellow, Pacific Northwest National Laboratory, Richtend, WA


    Paper ID: STP11246S

    Committee/Subcommittee: E10.02

    DOI: 10.1520/STP11246S


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