STP1046V2

    Experimental Assessments of Gundremmingen RPV Archival Material for Fluence Rate Effects Studies

    Published: Jan 1990


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    Abstract

    The 250-MW, boiling-water Gundremmingen reactor KRB-A in the Federal Republic of Germany (FRG) has been decommissioned. A joint USA/FRG/UK study, conceived by the U.S. Nuclear Regulatory Commission (NRC), is underway to evaluate material removed from the vessel for a critical assessment of power reactor versus test reactor environment effects. The vessel operated at ∼288°C; the inner-wall fluence estimate at decommissioning was about 1×1019n/cm2, E>1MeV.

    This report describes test reactor irradiation assessments of a forging segment believed to be archive material from the KRB-A vessel fabrication. Charpy-V (Cv), compact tension (CT), and tension test specimens were evaluated in five as-irradiated conditions and two postirradiation annealed conditions. With 288°C irradiations, the elevation in 100 MPa · m1/2 temperature was found to match the elevation in 41-J temperature within 12°C. The latter elevation was predicted well by NRC's Regulatory Guide 1.99.

    The L-C orientation data for the archive material versus the vessel trepans suggest a fluence-rate effect. However, the C-L orientation data do not. A test orientation dependence of radiation embrittlement sensitivity, described by the trepan material, but not the archive material, is responsible and is anomalous.

    Keywords:

    Gundremmingen KRB-A reactor, pressure vessels, radiation embrittlement, notch ductility, fracture toughness, neutron dosimetry, 20NiMoCr26 steel, A336 steel, test reactor, Charpy-V test, compact tension test, postirradiation annealing, J-R curve, fluence rate effects


    Author Information:

    Hawthorne, J. Russell
    Senior metallurgist, Materials Engineering Associates, Inc., Lanham, MD

    Hiser, Allen L.
    Engineer, Materials Engineering Associates, Inc., Lanham, MD


    Paper ID: STP49444S

    Committee/Subcommittee: E10.07

    DOI: 10.1520/STP49444S


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