Analysis of the Belgian Surveillance Fracture Toughness Database Using Conventional and Advanced Master Curve Approaches

    Volume 6, Issue 3 (March 2009)

    ISSN: 1546-962X

    CODEN: JAIOAD

    Published Online: 23 February 2009

    Page Count: 8


    Lucon, Enrico
    SCK⋅CEN, Institute for Nuclear Material Science, Mol,

    Scibetta, Marc
    SCK⋅CEN, Institute for Nuclear Material Science, Mol,

    Gérard, Robert
    Tractebel Engineering-Suez, Brussel,

    (Received 20 May 2008; accepted 17 January 2009)

    Abstract

    The “classical” regulatory approach to the analysis of surveillance capsules in nuclear power plants entails an indirect estimate of the fracture toughness of the beltline materials, by inferring rather than measuring their toughness properties. Indeed, the irradiation-induced shift of the fracture toughness curve is assumed to be equal to the shift of the Charpy absorbed energy transition curve at a predefined level (41 J). An alternative surveillance approach, primarily based on direct fracture toughness measurements in the ductile-to-brittle transition region using the Master Curve procedure, has been applied to surveillance materials from several Belgian nuclear power plants in the past 15 years. This has led to the establishment of a significant database, consisting of 292 fracture toughness data points for 23 material conditions (unirradiated materials and surveillance capsules). In this study, different temperature normalization approaches are applied to the available data. The analyses show that data clearly follow the Master Curve formalism. Moreover, it is confirmed that both the static (KIc) and the dynamic (KIR) curves of the ASME Code Section XI provide an effective lower bound to the measured results, although more conservatism is evident when using RTNDT as the normalization parameter. Both the conventional (ASTM E1921-08, ‘‘Standard Test Method for Determination of Reference Temperature, T0, for Ferritic Steels in the Transition Range’’) and advanced (Multi-Modal) Master Curve analyses of the database clearly demonstrate that normalizing data by (TRTT0) provides the best rationalization of the available information and the most effective representation of the experimental scatter.


    Paper ID: JAI101897

    DOI: 10.1520/JAI101897

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    Author
    Title Analysis of the Belgian Surveillance Fracture Toughness Database Using Conventional and Advanced Master Curve Approaches
    Symposium Presented at the ASTM 24th Symposium on Effects of Radiation on Nuclear Materials and the Nuclear Fuel Cycle, 2008-06-26
    Committee E10