The probability of detection (POD), often calculated statistically from experimental data, represents the ability of an inspection to detect a given flaw. The object of this work is to simulate the POD of a reference flaw called "Flat-Bottom Hole" (FBH) present within a pipe wall during an ultrasonic inspection, which is a method commonly employed at Vallourec mills for controlling seamless steel pipes. The simulation is based on a simple concept: to detect the FBH, the ultrasonic wave must be reflected by it, which is only the case when the transducer and the FBH are in front of one another. This POD modelling is a function of the pulse repetition frequency of the electronics, the user-defined alarm filtering algorithm, as well as the dimensions, linear and rotational speed of the pipe. In addition, this model takes into account the intensity and shape of the emission field from the transducer as well as the ability of the FBH to reflect the ultrasounds to compute a theoretical signal amplitude as a function of the relative positions of the pipe and the transducer.
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