Analysis of the Belgian surveillance fracture toughness database using conventional and advanced master curve approaches

Enrico Lucon, Marc Scibetta, Robert Gérard

    Research outputpeer-review

    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 (T-RTT0) provides the best rationalization of the available information and the most effective representation of the experimental scatter.

    Original languageEnglish
    Title of host publicationEffects of Radiation on Nuclear Materials and the Nuclear Fuel Cycle
    Subtitle of host publication24th Volume
    PublisherASTM International
    Pages26-39
    Number of pages14
    ISBN (Print)9780803134256
    DOIs
    StatePublished - 2010
    Event24th ASTM Symposium on Effects of Radiation on Nuclear Materials and the Nuclear Fuel Cycle - ASTM, Denver, Colorado
    Duration: 24 Jun 200826 Jun 2008

    Publication series

    NameASTM Special Technical Publication
    Volume1513 STP
    ISSN (Print)0066-0558

    Conference

    Conference24th ASTM Symposium on Effects of Radiation on Nuclear Materials and the Nuclear Fuel Cycle
    Country/TerritoryUnited States
    CityDenver, Colorado
    Period2008-06-242008-06-26

    ASJC Scopus subject areas

    • General Materials Science

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