AUSTENITIC STEEL PIPING TESTING EXERCISES IN PISC

In this paper capability and reliability studies of NDT procedures for the inspection of wrought and cast stainless steel piping used in nuc lear power plants will be presented. The capability study was designed to identify procedures that have the potential to detect and size def ects and to discriminate between flawed and unflawed material. The rel iability study was undertaken to quantify on real and realistic flaws in-service inspection performance (detection and false call capability ) under realistic field conditions. Furthermore parametric studes were performed to complement the capability and reliability studies by eva luating the effect of important material and flaw variables. The speci mens used in these studies were cast-to-cast, cast-to-wrought, and wro ught-to-wrought pipework welds. The evaluation methods used to quantif y the inspection performance were selected to be as comparable as poss ible to the PISC II methods. These were adapted to allow also the eval uation of the effect of false calls. During the PISC II screening exer cise for the cast-to-cast stainless steel round robin test and other p iping round robin studies, it was indeed found that false call probabi lities were large and could not be ignored in the evaluation of the in spection performance. The matrix of samples has also been designed to allow the implementation of specific statistical analysis procedures f or the evaluation of results such as for example the relative operativ e characteristics analysis.