SAFT-UT field experience

This paper reports on a three-year program at the Battelle, Pacific Northwest Laboratory to transfer the synthetic aperture focusing technique (SAFT) technology that was developed at the University of Michigan into the field. A brief overview is given of the program and the field system is described. The main portion of the paper is devoted to the experience of using the SAFT system in a third-party role to aid in resolving inspection inconsistencies between several different UT inservice inspections results for intergranular stress corrosion cracks (IGSCC) in boiling water reactor (BWR) piping. A new method of scanning using a modified tandem technique (called TSAFT) was also developed and successfully employed in the field. The SAFT images made cracks easy to identify and the TSAFT data were easy to interpret for depth sizing. However, the most significant fact about the system is that it did work very well under field conditions even though a number of improvements were identified as a result of each field trip. These improvements are discussed in the paper