Ultrasound for nuclear reactors

Ultrasonic methods offer the potential for Structural Health Monitoring of critical components in nuclear reactors. These efforts have been limited by ultrasonic transducers incapable of performance under high temperatures and/or irradiation conditions. Here we report on piezoelectric transducers designed, fabricated, tested and optimized to perform in harsh environments. Test capsules with piezoelectric transducers were fabricated with Aluminum Nitride (AlN), Zinc Oxide (ZnO), and Bismuth Titanate (BiTi) as the active elements. Measurements were performed in the MIT Reactor for 18 months. The transducers experienced an integrated neutron fluence of approximately 8.68 E + 20 n/cm2 for n u003e1 MeV, temperatures in excess of 420 °C, and a gamma fluence of 7.23 Gy/cm2. The AlN transducer acoustically coupled to a Kovar cylinder gave acceptable pulse-echo data throughout the test. We show a summary of the test results. Thus the feasibility of ultrasonic transducers in a nuclear reactor has been established and o...