Monitoring Large Superconducting Magnets Using Acoustic Emission Technology

Acoustic Emission (AE) techniques are used to study the structural integrity of large superconducting magnets, particularly of fusion-device scale. The Large Coil Task (LCT) at Oak Ridge National Laboratory is designed to test six large superconducting coils in a tokamak configuration. We have used the LCT to explore long-term trends in AE characteristics and to develop improved methods for data acquisition and processing. Thirty differential AE sensors were strategically mounted onto the General Dynamics LCT Coil. This coil and the JAERI coil were tested during the Partial Array Test in the summer of 1984. Since the General Dynamics coil has not failed at this time, it is not possible to determine finally which AE parameters will best characterize magnet performance. Presented here are spatial distributions of AE trends which were observed and can be expected for this style of superconducting coil.