SUMMARY The Time-of-Flight Diffraction (TOFD) technique has been used to monitor the heights of defects in welds of a vessel that has been in operation for 25 years. Regular monitoring of defect height provides a check that the defects are stable. Satisfactory results mean that the vessel can be kept in operation for a further period. The TOFD technique has been selected for its high sizing accuracy, as this allows a high level of reproducibility to be achieved. This presentation will describe the approach to this monitoring problem, as well as the preparations and the formulation of the criteria used to judge future results on the presence of growth.

S. Terpstra

Papers

Monitoring heights of defects in welds using the ultrasonic time-of-flight diffraction technique