The need to qualify non-destructive testing systems (NDT systems) for pre- and in-service inspection has been recognised to a greater or lesser extent for many years in many countries engaged in nuclear power generation. However, NDT in general and qualification of NDT systems in particular are multidisciplinary and complex tasks. Development of NDT systems and demonstration of their effectiveness by qualifications require good knowledge in the NDT methods and techniques that are to be used as well as the influence from component geometry, material structure, defect morphologies, NDT operator (personnel) performance in different situations.
The representativeness of defects in the qualification test blocks is a key point in any practical assessment of NDT systems. The response of the defects used, with respect to the actual NDT system, must therefore adequately represent the response of the expected or observed real defects.
In 1994, SKI therefore initiated a work to characterize a number of morphology parameters for common crack mechanisms. The analysis was structured in a certain way to obtain consistency in future reporting as well as make further statistical evaluations and comparisons possible.
In 2005, this project was initiated to follow up the first project and to obtain even better statistical data.