Post-Irradiation Tensile Behavior and Residual Activity of Several Ferritic/Martensitic and Austenitic Steels Irradiated in Osiris Reactor at 325°C up to 9 dpa

    Volume 2, Issue 8 (September 2005)

    ISSN: 1546-962X

    CODEN: JAIOAD

    Published Online: 22 June 2005

    Page Count: 19


    de Carlan, Y
    Commissariat à l'Energie Atomique, CEA-Saclay, Gif-Sur-Yvette,

    Averty, X
    Commissariat à l'Energie Atomique, CEA-Saclay, Gif-Sur-Yvette,

    Brachet, J-C
    Commissariat à l'Energie Atomique, CEA-Saclay, Gif-Sur-Yvette,

    Bertin, J-L
    Commissariat à l'Energie Atomique, CEA-Saclay, Gif-Sur-Yvette,

    Rozenblum, F
    Commissariat à l'Energie Atomique, CEA-Saclay, gif-Sur-Yvette,

    Rabouille, O
    Commissariat à l'Energie Atomique, CEA-Saclay, Gif-Sur-Yvette,

    Bougault, A
    Commissariat à l'Energie Atomique, CEA-Saclay, Gif-Sur-Yvette,

    (Received 15 April 2004; accepted 6 March 2005)

    Abstract

    An experimental irradiation, named “Alexandre,” has been carried out in the Osiris experimental reactor to perform a generic study on the mechanical behavior after irradiation at 325°C of different kinds of steels suitable for use as irradiated components in a nuclear reactor [1]. The irradiated steels were austenitic stainless, martensitic (conventional and reduced activation), and ferritic-martensitic Oxide Dispersion Strengthened steels in various initial metallurgical conditions. The final dose was 9 dpa, which represents nearly a “saturation” dose for the hardening/embrittlement of both austenitic and martensitic steels. At this dose, the Yield Strength and the Ultimate Tensile Strengths are almost equal, and strong localization of the plastic deformation is often observed.

    After irradiation, as-quenched martensitic steels exhibit very large tensile strengths, and some of them show ductility parameters comparable with those of the tempered martensitic steels. At 9 dpa, the behavior of cold-worked steels tends to be similar to that of tempered steels with a more pronounced localization of the deformation. This indicates that the recovery of the cold-worked microstructure is not achieved at 9 dpa. Certain martensitic steels (MANET II and HT9) show tendencies to brittle behavior and exhibit a considerable degradation of their ductility parameters after irradiation. The behavior of the most chromium-rich ferritic steel (ODS-MA957) is quite surprising. It exhibits moderate hardening and good post-irradiation ductility parameters.

    Measurements of the dose rate have been performed after several cooling-times, of up to 53 months after unloading, to study the radioactive decay of the steels. Experimental data show that the reduced activation steels exhibit the lowest residual activity and the highest rate of relative activity decrease (90 %) during the cooling period.


    Paper ID: JAI12354

    DOI: 10.1520/JAI12354

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    Author
    Title Post-Irradiation Tensile Behavior and Residual Activity of Several Ferritic/Martensitic and Austenitic Steels Irradiated in Osiris Reactor at 325°C up to 9 dpa
    Symposium Effects of Radiation on Materials: 22nd International Symposium, 2004-06-10
    Committee E10