Comparison of Artificial flaws in Austenitic Steel Welds with NDE Methods

Ari Koskinen, Esa Leskelä

    Research output: Chapter in Book/Report/Conference proceedingConference article in proceedingsScientific

    Abstract

    Qualification of non-destructive examination (NDE) procedures for in-service inspections (ISI) of nuclear power plant (NPP) components is performed using different types of artificial flaws. The assessment of the reliability of a procedure requires representative flaws compared to the real service-induced flaws. Fatigue cracks can nowadays be produced artificially as thermal fatigue or mechanical fatigue cracks. Thermal fatigue crack production is very well controlled in matter of size and opening. That kind of cracks are very realistic option compared to the real service-induced cracks. Mechanical fatigue crack production is well known and widely used method and can produce very realistic cracks as well. The aim of the study is to get a wider perspective to the differences in similar type of flaws from different manufacturers. Ultrasonic indications are highly dependent on defect characteristics like roughness, crack opening, tilt and branching. This work studies the influence of different reflector properties on flaw indications. Two kinds of artificially produced cracks from different manufactures and one EDM (electric discharge machining) reference notch were made in welded austenitic stainless steel test blocks. Flaws were examined using conventional ultrasonic testing (UT), phased array ultrasonic testing (PAUT) and computed tomography (CT). The flaws were sized with different techniques and those results are compared to the true state flaw dimensions as determined by destructive analysis. This study was made as a part of Finnish national research program on NPP safety 2010-2014 (SAFIR2014), Monitoring of the structural integrity of materials and components in reactor circuit, MAKOMON project.
    Original languageEnglish
    Title of host publicationProceedings of the 11th international conference on NDE in relation to structural integrity for nuclear and pressurized components
    PublisherEuropean Union
    ISBN (Print)978-92-79-57266-1
    DOIs
    Publication statusPublished - 2015
    MoE publication typeB3 Non-refereed article in conference proceedings
    Event11th International Conference on NDE in Relation to Structural Integrity for Nuclear and Pressurized Components - Jeju Island, Korea, Democratic People's Republic of
    Duration: 19 May 201521 May 2015
    Conference number: 11

    Conference

    Conference11th International Conference on NDE in Relation to Structural Integrity for Nuclear and Pressurized Components
    CountryKorea, Democratic People's Republic of
    CityJeju Island
    Period19/05/1521/05/15

    Keywords

    • ultrasonic testing (UT)
    • phased array
    • computed tomography
    • mechanical fatigue crack
    • thermal fatigue crack
    • indication
    • flaw
    • flaw sizing
    • Scanning Electron Microscope (SEM)
    • destructive testing

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