Trend of UT Performance on Wrought Stainless Steel
P.G. Heasler, S.R. Doctor, Pacific Northwest Lab. , Richland, USA
ABSTRACT
This paper summarises a comparison of and trends in UT performance quantified through round robin studies conducted on wrought stainless steel. These studies include a piping inspection round robin (PIRR) conducted in 1981-1982, a mini-round robin (MRR) conducted in 1986 and the PISC III Action 4 wrought-tp-wrought stainless steel studies conducted in 1990-1992. Although these three studies quantified UT performance, they employed different protocols for conducting the testing and in scoring the results. Therefore, the first task was to put the data into a common database so that meaningful comparisons could be made. The second task was to define the measurement parameters to be used for quantifying UT performance and then to reanalyse all of the data using these parameters. The statistical models and processes that were applied are defined. Four variance terms in the models were used to describe measurement bias, and contributions of team-to-team, flaw-to-flaw and measurement variability. This work focused on detection performance using probability of detection logistic regression analysis. Depth sizing and length sizing analysis were also conducted using a linear regression model. In summary, the three round robin studies show that there has been a clear and significant improvement in the capability of procedures/equipment/personnel to more reliably detect and to more accurately size cracks in wrought stainless steel piping over the 10 years when these studies were conducted.
Publication Source: First International Conference on NDE in Relation to Structural Integrity for Nuclear and Pressurised Components , 20 - 22 October 1998, Amsterdam, Netherlands. Held by the Joint Research Centre of the European Commission. Publisher:Woodhead Publishing Limited
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