Since the 1940’s, the accepted inspection method for structural welds in the U.S. Navy has been radiography (RT). This technique has been accepted as an inspection method for welds since the 1940’s. A major advantage of radiography compared to other inspection techniques is the availability of objective quality evidence, the radiograph, as a permanent record of the inspection. Radiography has gained precedence as the inspection method to prescribe for these welds because this permanent record is perceived to evince all discontinuities and facilitates auditing. This technique and the criteria used to accept or reject discontinuities have generally proved adequate although technical limitations and cost disadvantages have been encountered.