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

Enrico Lucon, Marc Scibetta, Robert Gérard

    Research outputpeer-review


    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.
    Original languageEnglish
    Pages (from-to)1-8
    JournalJournal of ASTM International
    Issue number3
    StatePublished - Mar 2009
    Event24th ASTM Symposium on Effects of Radiation on Nuclear Materials and the Nuclear Fuel Cycle - ASTM, Denver, Colorado
    Duration: 24 Jun 200826 Jun 2008

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