Conservatism of ASME KIR-reference curve with respect to crack arrest

Kim Wallin (Corresponding Author), Rauno Rintamaa, G. Nagel

    Research output: Contribution to journalArticleScientificpeer-review

    12 Citations (Scopus)

    Abstract

    The conservatism of the RTNDT temperature indexing parameter and the ASME KIR-reference curve with respect to crack arrest toughness, has been evaluated. Based on an analysis of the original ASME KIa data, it was established that inherently, the ASME KIR-reference curve corresponds to an overall 5% lower bound curve with respect to crack arrest. It was shown that the scatter of crack arrest toughness is essentially material independent and has a standard deviation (S.D.) of 18% and the temperature dependence of KIa has the same form as predicted by the master curve for crack initiation toughness. The ‘built in’ offset between the mean 100 MPa√m crack arrest temperature, TKIa, and RTNDT is 38°C (TKIa=RTNDT+38°C) and the experimental relation between TKIa and NDT is, TKIa=NDT+28°C. The KIR-reference curve using NDT as reference temperature will be conservative with respect to the general 5% lower bound KIa(5%)-curve, with a 75% confidence. The use of RTNDT, instead of NDT, will generally increase the degree of conservatism, both for non-irradiated as well as irradiated materials, close to a 95% confidence level. This trend is pronounced for materials with Charpy-V upper shelf energies below 100 J. It is shown that the KIR-curve effectively constitutes a deterministic lower bound curve for crack arrest The findings are valid both for nuclear pressure vessel plates, forgings and welds.
    Original languageEnglish
    Pages (from-to)185-199
    Number of pages15
    JournalNuclear Engineering and Design
    Volume206
    Issue number2-3
    DOIs
    Publication statusPublished - 2001
    MoE publication typeA1 Journal article-refereed

    Fingerprint

    crack arrest
    crack
    Nondestructive examination
    Cracks
    Toughness
    curves
    toughness
    temperature
    Forgings
    Temperature
    confidence
    Pressure vessels
    Crack initiation
    Welds
    pressure vessels
    forging
    crack initiation
    vessel
    shelves
    standard deviation

    Cite this

    Wallin, Kim ; Rintamaa, Rauno ; Nagel, G. / Conservatism of ASME KIR-reference curve with respect to crack arrest. In: Nuclear Engineering and Design. 2001 ; Vol. 206, No. 2-3. pp. 185-199.
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    abstract = "The conservatism of the RTNDT temperature indexing parameter and the ASME KIR-reference curve with respect to crack arrest toughness, has been evaluated. Based on an analysis of the original ASME KIa data, it was established that inherently, the ASME KIR-reference curve corresponds to an overall 5{\%} lower bound curve with respect to crack arrest. It was shown that the scatter of crack arrest toughness is essentially material independent and has a standard deviation (S.D.) of 18{\%} and the temperature dependence of KIa has the same form as predicted by the master curve for crack initiation toughness. The ‘built in’ offset between the mean 100 MPa√m crack arrest temperature, TKIa, and RTNDT is 38°C (TKIa=RTNDT+38°C) and the experimental relation between TKIa and NDT is, TKIa=NDT+28°C. The KIR-reference curve using NDT as reference temperature will be conservative with respect to the general 5{\%} lower bound KIa(5{\%})-curve, with a 75{\%} confidence. The use of RTNDT, instead of NDT, will generally increase the degree of conservatism, both for non-irradiated as well as irradiated materials, close to a 95{\%} confidence level. This trend is pronounced for materials with Charpy-V upper shelf energies below 100 J. It is shown that the KIR-curve effectively constitutes a deterministic lower bound curve for crack arrest The findings are valid both for nuclear pressure vessel plates, forgings and welds.",
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    Conservatism of ASME KIR-reference curve with respect to crack arrest. / Wallin, Kim (Corresponding Author); Rintamaa, Rauno; Nagel, G.

    In: Nuclear Engineering and Design, Vol. 206, No. 2-3, 2001, p. 185-199.

    Research output: Contribution to journalArticleScientificpeer-review

    TY - JOUR

    T1 - Conservatism of ASME KIR-reference curve with respect to crack arrest

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    AU - Rintamaa, Rauno

    AU - Nagel, G.

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    N2 - The conservatism of the RTNDT temperature indexing parameter and the ASME KIR-reference curve with respect to crack arrest toughness, has been evaluated. Based on an analysis of the original ASME KIa data, it was established that inherently, the ASME KIR-reference curve corresponds to an overall 5% lower bound curve with respect to crack arrest. It was shown that the scatter of crack arrest toughness is essentially material independent and has a standard deviation (S.D.) of 18% and the temperature dependence of KIa has the same form as predicted by the master curve for crack initiation toughness. The ‘built in’ offset between the mean 100 MPa√m crack arrest temperature, TKIa, and RTNDT is 38°C (TKIa=RTNDT+38°C) and the experimental relation between TKIa and NDT is, TKIa=NDT+28°C. The KIR-reference curve using NDT as reference temperature will be conservative with respect to the general 5% lower bound KIa(5%)-curve, with a 75% confidence. The use of RTNDT, instead of NDT, will generally increase the degree of conservatism, both for non-irradiated as well as irradiated materials, close to a 95% confidence level. This trend is pronounced for materials with Charpy-V upper shelf energies below 100 J. It is shown that the KIR-curve effectively constitutes a deterministic lower bound curve for crack arrest The findings are valid both for nuclear pressure vessel plates, forgings and welds.

    AB - The conservatism of the RTNDT temperature indexing parameter and the ASME KIR-reference curve with respect to crack arrest toughness, has been evaluated. Based on an analysis of the original ASME KIa data, it was established that inherently, the ASME KIR-reference curve corresponds to an overall 5% lower bound curve with respect to crack arrest. It was shown that the scatter of crack arrest toughness is essentially material independent and has a standard deviation (S.D.) of 18% and the temperature dependence of KIa has the same form as predicted by the master curve for crack initiation toughness. The ‘built in’ offset between the mean 100 MPa√m crack arrest temperature, TKIa, and RTNDT is 38°C (TKIa=RTNDT+38°C) and the experimental relation between TKIa and NDT is, TKIa=NDT+28°C. The KIR-reference curve using NDT as reference temperature will be conservative with respect to the general 5% lower bound KIa(5%)-curve, with a 75% confidence. The use of RTNDT, instead of NDT, will generally increase the degree of conservatism, both for non-irradiated as well as irradiated materials, close to a 95% confidence level. This trend is pronounced for materials with Charpy-V upper shelf energies below 100 J. It is shown that the KIR-curve effectively constitutes a deterministic lower bound curve for crack arrest The findings are valid both for nuclear pressure vessel plates, forgings and welds.

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