Using Phased Array Ultrasonic Testing in Lieu of Radiography for Acceptance of Carbon Steel Plate Welds

The Pacific Northwest National Laboratory (PNNL) is conducting studies for the U.S. Nuclear Regulatory Commission (NRC) to assess the capability, effectiveness, and reliability of ultrasonic testing (UT) as a replacement method for radiographic testing (RT) for volumetric examination of nuclear power plant (NPP) components. This particular study focused on evaluating the use of phased-array (PA) UT on carbon steel plate welds. Welding fabrication flaws included a combination of planar and volumetric types; for example, incomplete fusion, lack of penetration, cracks, porosity, and slag inclusions. The examinations were conducted using PAUT techniques applied primarily for detection and flaw type characterization. This paper will discuss the results of using PAUT in lieu of RT for detection and classification of fabrication flaws in carbon steel plate welds.