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SAFT and TOFD—A Comparative Study of Two Defect Sizing Techniques on a Reactor Pressure Vessel Mock-up

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Abstract

Defect sizing is required for a quantitative assessment of the quality and reliability of safety relevant components and materials using ultrasonic non-destructive testing. The SAFT (Synthetic Aperture Focussing Technique) and the TOFD technique (Time Of Flight Diffraction) are such promising sizing candidates, extracting more information from the raw ultrasound echo data and the corresponding crack tip response. In this work the phased array technique is used to inspect a clad mock-up model of a pressure vessel section. The full scale model contains artificial test reflectors which are located in the weld and in the cladding region as well. The defects—representing typical flaws at a very early stage—are analysed with different frequencies, beam angles and directions of incidence.

For the reconstruction of reflector indications a SAFT algorithm is applied to the phased array measurement results. Additionally the reflectors are analysed by means of the TOFD technique, using different beam angles at the same time. Both analysis methods are performed using different directions of incidence considering the complex cladding structure underneath the inner surface of the mock-up model. A direct comparison of the SAFT and TOFD techniques shows that, besides the clarity of the results, the detection and sizing capabilities of SAFT are far better.

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Acknowledgements

The author wish to thank D. Szabo, K. Kuti and G. Paczolay from Paks Nuclear Power Plant for making this investigation possible and for their support during our stay in Hungary.

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Authors and Affiliations

  1. Division 8.4, BAM Federal Institute for Materials Research and Testing, Unter den Eichen 87, 12205, Berlin, Germany

    Jens Prager, Jessica Kitze, Cécile Acheroy, Daniel Brackrock, Gerhard Brekow & Marc Kreutzbruck

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  1. Jens Prager
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  2. Jessica Kitze
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  3. Cécile Acheroy
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  4. Daniel Brackrock
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  5. Gerhard Brekow
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  6. Marc Kreutzbruck
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Correspondence to Jens Prager.

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Prager, J., Kitze, J., Acheroy, C. et al. SAFT and TOFD—A Comparative Study of Two Defect Sizing Techniques on a Reactor Pressure Vessel Mock-up. J Nondestruct Eval 32, 1–13 (2013). https://doi.org/10.1007/s10921-012-0153-9

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  • DOI: https://doi.org/10.1007/s10921-012-0153-9

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