Optimized eddy current detection of small cracks in steam generator tubing

A complete, computer based design methodology is described, aiming to develop an eddy current sensor with increased sensitivity to flaws, and reduced sensitivity to probe lift-off. The first part of the paper contains an analysis performed in order to establish detailed criteria for an effective design. Numerical investigations have been carried out and their results are discussed, regarding various problems of detectability and lift-off noise level. Based on these results, in the second part two probe arrangements are proposed, and it is shown how their performance parameters could be further improved.