Laboratory techniques verified on customer mock-ups were used to phase out use of radiography. Further requirements to
satisfy the customer's concerns involved site trials. Therefore, several hundred welds tested by mechanised UT were
compared with radiography. It was seen that all significant defects found using radiography were also detected using
mechanised UT. It was concluded that mechanised ultrasonics was an effective replacement for radiography and offered a
comparable confidence level in probability of detection of all significant defects.