## Abstract

The conservatism of the RT

_{NDT}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 K_{Ia}data, it was established that inherently, the ASME K_{IR}-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 K_{Ia}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, TK_{Ia}, and RT_{NDT}is 38°C (TK_{Ia}=RT_{NDT}+38°C) and the experimental relation between TK_{Ia}and NDT is, TK_{Ia}=NDT+28°C. The K_{IR}-reference curve using NDT as reference temperature will be conservative with respect to the general 5% lower bound K_{Ia}(5%)-curve, with a 75% confidence. The use of RT_{NDT}, 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 K_{IR}-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 language | English |
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Pages (from-to) | 185-199 |

Number of pages | 15 |

Journal | Nuclear Engineering and Design |

Volume | 206 |

Issue number | 2-3 |

DOIs | |

Publication status | Published - 2001 |

MoE publication type | A1 Journal article-refereed |

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