Eddy current data union

#1. Field of the Invention

#This invention pertains generally to eddy current data obtained from the nondestructive examination of a component and, more particularly, to a method of synthesizing eddy current data to be used for training data analysts and/or testing inspection techniques.

#2. Related Art

#A further understanding of the invention can be gained from the following description of the preferred embodiments when read in conjunction with the accompanying drawings in which:

#FIG. 1 is a perspective view of a portion of a steam generator tube in which an eddy current probe is about to be inserted; and

#FIG. 2 is a flow chart of the steps of the method of this invention.

#The invention provides for the injection of electronic nondestructive examination signals either from field data or data obtained from specimens, into a data stream to produce a data set that is the combination of the two data sets, i.e., the basic data stream plus the injected signal. In this example, the field data is obtained from the inspection of steam generator heat exchange tubing, figuratively shown in FIG. 1 by reference character 10, with an eddy current probe 11. For the purpose of the following description, the data obtained from the specimen will also be referred to as laboratory data, because it can be obtained at a site remote from the field. However, it should be appreciated that the location where the specimen data is collected is not pertinent to the broad aspects of this invention. Additionally, this invention can be applied to injecting one set of field data into another set of field data in the-same manner as will be described hereafter. The focus, however, of the preferred embodiment described hereafter will be on inserting specimen obtained data because of the ease of engineering the specimen to replicate a number of flaws of interest. By injecting the field data into the laboratory data or the laboratory data into the field data, data that is characteristic of the “noise” that might be encountered in a field inspection, from a specific nuclear power generating facility, can be combined with the data from the laboratory produced discontinuity responses. The net result is a data set that has the discontinuity response somewhat masked by the field noise. These data sets can then be used to train or test analysts on the impact of noise on the anticipated degradation responses. Further data sets produced by the combination process of this invention can be used to determine the impact of noise on the probability of detection of a flaw and on the uncertainties in detecting a given flaw of various sizes.

#A flow chart of the overall data combination process of this invention is shown in FIG. 2. This process can be readily implemented by data management software such as the Westinghouse Advanced Network Sharing Eddy current Resources-ANSER™-software licensable from Westinghouse Electric Company, LLC, Monroeville, Pa. The ANSER ™ software is an eddy current acquisition, analysis and database management tool that runs on a UNIX® based work station. Another alternative would be to use the EDDYNET™ software licensable from Zetec Corp., Washington State. Preferably, both data sets involved in the combination process should be acquired using similar inspection conditions, i.e., probe type (coil diameter), inspection frequencies, data rates (samples/inch), etc. If there are differences in the inspection conditions, mathematical models can be used to interpolate one or the other of the responses if coil size or inspection frequencies are not identical.

#The first steps 12 and 14 in the data injection process are to define the calibration or normalization parameters for each data set A & B. Preferably, at least one of the standard holes or notches in a calibration standard used for this purpose should be identical for both data sets. If they are not identical, mathematical models can be used as a basis for interpolation of one or the other of the data sets. The calibration standard is a specimen created in accordance with the ASME code. Each of the data sets is then calibrated so that the reference discontinuity response for the two data sets, A and B, is identical. For bobbin coil eddy current data, this can be accomplished by setting the voltage of the 20% holes, i.e., 20% through-wall flaw, to 4 volts and the phase of the through-wall hole to a 40° rotation. For rotating probe data, the through-notch in the calibration standard can be used to set the phase and amplitude. For most applications, it can be assumed that the accuracy of the standard is sufficient so that cross calibration of the standards is not required.