Position-based sampling for eddy current inspection of steam generator tubes

An inspection system usable to perform an inspection of a steam generator that comprises a plurality of tubes, the inspection system comprising:

• an eddy current probe comprising an eddy current sensor that is structured to output an eddy current signal;
• a drive mechanism that is cooperable with the eddy current probe to move the eddy current sensor with respect to a tube of the plurality of tubes, the drive mechanism comprising an encoder that is structured to generate a series of outputs, each output of the series of outputs being representative of a successive movement of a predetermined distance of the eddy current sensor with respect to the tube;
• a computer that is structured to detect the series of outputs and to record the eddy current signal, the computer comprising a processor apparatus that comprises a processor and a storage, the storage having stored therein a number of routines which, when executed on the processor, cause the inspection system to perform operations comprising:
• operating the drive mechanism to move the eddy current sensor with respect to the tube;
• outputting from the encoder the series of outputs;
• employing the computer to detect the series of outputs;
• and
• responsive to each of at least some of the outputs of the series of outputs, triggering the computer to store the eddy current signal;
• wherein the tube has a first straight portion, a second straight portion, and a bend situated between the first and second straight portions, and wherein the operations further comprise:
• accelerating the eddy current sensor to be moving at a first velocity within the first straight portion in a direction toward the bend;
• and
• decelerating the eddy current sensor to be moving at a second velocity less that the first velocity within the first straight portion in a direction toward the bend as the eddy current sensor reaches the bend.