Studies on the effect of flaw detection probability assumptions on risk reduction at non-destructive inspection

Kaisa Simola, Otso Cronvall, Ilkka Männistö, Jens Gunnars, Lars Alverlind, Peter Dillström, Luca Gandossi

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

    1 Citation (Scopus)


    Reliability estimates of piping (and other structural components) are needed e.g. in probabilistic safety assessment (PSA) studies, risk-informed ISI applications, and other structural reliability assessments. The reliability of piping components is affected by ISI, since inspection results increase the knowledge of the state of the inspected components. Probabilistic fracture mechanics (PFM) models can account for the ISI effectiveness and interval, and allow sensitivity studies. A detailed modelling of ISI effectiveness is difficult, since it depends on several factors, and it would be very expensive to produce statistical data to estimate the probability of detection (POD) for various flaws. On the other hand, one could question the need of very detailed POD estimates in RI-ISI applications. If sufficient risk reduction can be shown by using simplified (conservative) POD estimates, more complex PODs are not needed. The paper summarises the results of a study of the effect of piping inspection reliability assumptions on failure probability using structural reliability models. The main interest was to investigate whether it is justifiable to use a simplified probability of detection (POD) curve. Further, the study compared various structural reliability calculation approaches for a set of cases. The results indicate that the use of a simplified POD could be justifiable in RI-ISI applications.
    Original languageEnglish
    Title of host publicationReliability, Risk and Safety
    Subtitle of host publicationBack to the Future
    EditorsBen Ale, Ioannis Papazoglou, Enrico Zio
    Place of PublicationLondon
    PublisherTaylor & Francis
    ISBN (Print)978-0-415-60427-7
    Publication statusPublished - 2010
    MoE publication typeA4 Article in a conference publication
    EventEuropean Safety and Reliability Conference, ESREL 2010 - Rhodes, Greece
    Duration: 5 Sept 20109 Sept 2010


    ConferenceEuropean Safety and Reliability Conference, ESREL 2010
    Abbreviated titleESREL 2010


    • In-service inspection
    • probability of detection
    • probabilistic fracture mechanics


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