DURING THE FABRICATION of a boiler, pressure vessel, and such related components as boiling water reactor piping or steam generator tubes, various types of nondestructive inspection (NDI) are performed at several stages of processing, mainly for the purpose of controlling the quality of fabrication.
In-service inspection is used to detect the growth of existing flaws or the formation of new flaws. This can be done while the vessel is in operation or down for servicing. The inspection methods used include visual, radiographic, ultrasonic, liquid penetrant, magnetic particle, eddy current, and acoustic emission inspection, as well as replication microscopy and leak testing. The assurance of component quality depends largely on the adequacy of NDI equipment and procedures and on the qualification of personnel conducting the inspection.