Possibilities of in-service inspection of austenitic welded seams in pipework of PWR-reactor coolant systems

The demand for the possibility of in-service inspection of austenitic circumferential welds in the dimension range of DN greater than or equal to 100 and wall thickness greater than or equal to 10 mm led to comprehensive experiments and pre service inspections. The results show that through the examination technique presented here defects in the root area can be detected reliably from 2 mm depth onwards. For the austenitic pipework of the PWR reactor coolant system one strives to dispense with the fracture postulate for pipes in the dimension range of DN greater than or equal to 100 mm and wall thickness greater than or equal to 10 mm. In the discussion with the approval authorities it was agreed that the in-service inspection through nondestructive examination required as a result of this was considered sufficient for the imspection of the surface. The inspection of the outer surface of the welds can then be performed through the surface crack test method and the inner surface in the area of the weld root through ultrasonic examination