Low temperature crack propagation of nickel-based weld metals in hydrogenated PWR primary water

Matias Ahonen, Ulla Ehrnstén, Hannu Hänninen

    Research output: Chapter in Book/Report/Conference proceedingConference article in proceedingsScientificpeer-review

    Abstract

    The effect of hydrogenated PWR primary water on the Low Temperature Crack Propagation (LTCP) susceptibility of nickel based weld metals Alloy 182, 82, 152 and 52 was studied performing J-R -tests at a slow displacement rate in simulated low temperature PWR primary water. When tested in an environment with high hydrogen content (100 cm3 H2/kg H2O), all the studied materials showed a remarkable decrease in the fracture toughness (JIC or JQ) values compared with the air test results. Alloy 182 showed the lowest average fracture toughness values in each test environment. The results obtained at a lower hydrogen content (~30 cm3 H2/kg H2O) suggest, that Alloy 182 is the most susceptible nickel based weld metal to LTCP, especially at low hydrogen contents. Intergranular cracking was predominant when the JIC value was low. Test results of pure weld metal Alloys 182 and 52 were also compared with the results of dissimilar metal weld (DMW) specimens of Alloy 182 and 52. The pure weld metals were substantially more susceptible to LTCP than the DMW specimens. Pre-exposure to high temperature hydrogenated water did not affect the fracture toughness of any of the test materials. The degradation in toughness is assumed to be caused by a hydrogen-induced intergranular cracking mechanism, where the precipitates in the weld metals acting as hydrogen trapping sites play an important role. The LTCP susceptibility of the studied alloys is discussed based on the present hydrogen embrittlement mechanisms.
    Original languageEnglish
    Title of host publicationFontevraud 7
    Subtitle of host publicationContribution of materials investigations to improve the safety and performance of LWRs, 26-30 September, 2010, Avignon, France
    Number of pages11
    Publication statusPublished - 2010
    MoE publication typeNot Eligible

    Fingerprint

    Crack propagation
    Welds
    Nickel
    Metals
    Hydrogen
    Water
    Dissimilar metals
    Fracture toughness
    Temperature
    Hydrogen embrittlement
    Toughness
    Precipitates
    Degradation
    Air

    Keywords

    • nuclear
    • LTCP
    • hydrogen
    • Ni-based weld metals

    Cite this

    Ahonen, M., Ehrnstén, U., & Hänninen, H. (2010). Low temperature crack propagation of nickel-based weld metals in hydrogenated PWR primary water. In Fontevraud 7: Contribution of materials investigations to improve the safety and performance of LWRs, 26-30 September, 2010, Avignon, France
    Ahonen, Matias ; Ehrnstén, Ulla ; Hänninen, Hannu. / Low temperature crack propagation of nickel-based weld metals in hydrogenated PWR primary water. Fontevraud 7: Contribution of materials investigations to improve the safety and performance of LWRs, 26-30 September, 2010, Avignon, France. 2010.
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    abstract = "The effect of hydrogenated PWR primary water on the Low Temperature Crack Propagation (LTCP) susceptibility of nickel based weld metals Alloy 182, 82, 152 and 52 was studied performing J-R -tests at a slow displacement rate in simulated low temperature PWR primary water. When tested in an environment with high hydrogen content (100 cm3 H2/kg H2O), all the studied materials showed a remarkable decrease in the fracture toughness (JIC or JQ) values compared with the air test results. Alloy 182 showed the lowest average fracture toughness values in each test environment. The results obtained at a lower hydrogen content (~30 cm3 H2/kg H2O) suggest, that Alloy 182 is the most susceptible nickel based weld metal to LTCP, especially at low hydrogen contents. Intergranular cracking was predominant when the JIC value was low. Test results of pure weld metal Alloys 182 and 52 were also compared with the results of dissimilar metal weld (DMW) specimens of Alloy 182 and 52. The pure weld metals were substantially more susceptible to LTCP than the DMW specimens. Pre-exposure to high temperature hydrogenated water did not affect the fracture toughness of any of the test materials. The degradation in toughness is assumed to be caused by a hydrogen-induced intergranular cracking mechanism, where the precipitates in the weld metals acting as hydrogen trapping sites play an important role. The LTCP susceptibility of the studied alloys is discussed based on the present hydrogen embrittlement mechanisms.",
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    author = "Matias Ahonen and Ulla Ehrnst{\'e}n and Hannu H{\"a}nninen",
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    Ahonen, M, Ehrnstén, U & Hänninen, H 2010, Low temperature crack propagation of nickel-based weld metals in hydrogenated PWR primary water. in Fontevraud 7: Contribution of materials investigations to improve the safety and performance of LWRs, 26-30 September, 2010, Avignon, France.

    Low temperature crack propagation of nickel-based weld metals in hydrogenated PWR primary water. / Ahonen, Matias; Ehrnstén, Ulla; Hänninen, Hannu.

    Fontevraud 7: Contribution of materials investigations to improve the safety and performance of LWRs, 26-30 September, 2010, Avignon, France. 2010.

    Research output: Chapter in Book/Report/Conference proceedingConference article in proceedingsScientificpeer-review

    TY - GEN

    T1 - Low temperature crack propagation of nickel-based weld metals in hydrogenated PWR primary water

    AU - Ahonen, Matias

    AU - Ehrnstén, Ulla

    AU - Hänninen, Hannu

    N1 - Project code: 41755 Proc. on a CD-ROM, ISBN N/A

    PY - 2010

    Y1 - 2010

    N2 - The effect of hydrogenated PWR primary water on the Low Temperature Crack Propagation (LTCP) susceptibility of nickel based weld metals Alloy 182, 82, 152 and 52 was studied performing J-R -tests at a slow displacement rate in simulated low temperature PWR primary water. When tested in an environment with high hydrogen content (100 cm3 H2/kg H2O), all the studied materials showed a remarkable decrease in the fracture toughness (JIC or JQ) values compared with the air test results. Alloy 182 showed the lowest average fracture toughness values in each test environment. The results obtained at a lower hydrogen content (~30 cm3 H2/kg H2O) suggest, that Alloy 182 is the most susceptible nickel based weld metal to LTCP, especially at low hydrogen contents. Intergranular cracking was predominant when the JIC value was low. Test results of pure weld metal Alloys 182 and 52 were also compared with the results of dissimilar metal weld (DMW) specimens of Alloy 182 and 52. The pure weld metals were substantially more susceptible to LTCP than the DMW specimens. Pre-exposure to high temperature hydrogenated water did not affect the fracture toughness of any of the test materials. The degradation in toughness is assumed to be caused by a hydrogen-induced intergranular cracking mechanism, where the precipitates in the weld metals acting as hydrogen trapping sites play an important role. The LTCP susceptibility of the studied alloys is discussed based on the present hydrogen embrittlement mechanisms.

    AB - The effect of hydrogenated PWR primary water on the Low Temperature Crack Propagation (LTCP) susceptibility of nickel based weld metals Alloy 182, 82, 152 and 52 was studied performing J-R -tests at a slow displacement rate in simulated low temperature PWR primary water. When tested in an environment with high hydrogen content (100 cm3 H2/kg H2O), all the studied materials showed a remarkable decrease in the fracture toughness (JIC or JQ) values compared with the air test results. Alloy 182 showed the lowest average fracture toughness values in each test environment. The results obtained at a lower hydrogen content (~30 cm3 H2/kg H2O) suggest, that Alloy 182 is the most susceptible nickel based weld metal to LTCP, especially at low hydrogen contents. Intergranular cracking was predominant when the JIC value was low. Test results of pure weld metal Alloys 182 and 52 were also compared with the results of dissimilar metal weld (DMW) specimens of Alloy 182 and 52. The pure weld metals were substantially more susceptible to LTCP than the DMW specimens. Pre-exposure to high temperature hydrogenated water did not affect the fracture toughness of any of the test materials. The degradation in toughness is assumed to be caused by a hydrogen-induced intergranular cracking mechanism, where the precipitates in the weld metals acting as hydrogen trapping sites play an important role. The LTCP susceptibility of the studied alloys is discussed based on the present hydrogen embrittlement mechanisms.

    KW - nuclear

    KW - LTCP

    KW - hydrogen

    KW - Ni-based weld metals

    M3 - Conference article in proceedings

    BT - Fontevraud 7

    ER -

    Ahonen M, Ehrnstén U, Hänninen H. Low temperature crack propagation of nickel-based weld metals in hydrogenated PWR primary water. In Fontevraud 7: Contribution of materials investigations to improve the safety and performance of LWRs, 26-30 September, 2010, Avignon, France. 2010