The paper highlights the importance of not only selecting proper NDE Methods but also effectively controlling them to ensure such NDEs performed are in order. This is particularly emphasized in the context of project KARP, a nuclear chemical process plant, wherein huge quantum of stainless steel piping work has been carried out. The plant comprises a total of about 130 KM piping out of which SS process piping alone amounts to 80 KM. The entire process piping along with vessels have been located in tall concrete shielded cells forming a maze of complicated network of piping presenting difficulties for welding as well as for RT due to space constraints. In view of the all welded construction and complex network of piping and vessels the final pressure testing of the process systems is impracticable and hence NDE methods are relied upon for ensuring quality and reliability of the system.

In project KARP majority of the process piping are of size 25 mm NB Sch. 40 and below whose wall thickness is 3.3 mm and less respectively. In view of the wall thickness of the pipes being smaller gamma ray sources are not suitable for meeting the sensitivity criteria. Further, in small bore piping all the joints look alike in field, making correlation of the radiographs with actual joints difficult. In such a scenario it is all the more important that the NDE Methods are so controlled that errors are avoided. The control mechanisms which have been designed and followed in project KARP for ensuring the quality are discussed and particularly for radiographic examination, the controls such as random physical verification, correlation and audit radiography are presented.