33a. A radiation and temperature-tolerant plasma contact microphone for sensing ultrasonic acoustic emissions in fatiguing metal structures

Structural failure can be predicted by sensing ultrasonic acoustic emissions, spontaneously created when stress energy is released as metals fatigue due to a cyclic load. However, conventional piezoelectric sensors suffer rapid performance degradation when exposed to extreme temperatures and neutron radiation, limiting their ability to monitor the health of nuclear infrastructure. We will develop and evaluate the recently invented plasma contact microphone, which uses a gas discharge tube as its transducing element, for acoustic-emission sensing in harsh nuclear environments. The work will be done in collaboration with Mistras Group, a leading provider of acoustic-emission technologies and services for forty years. A proof-of-concept version of the plasma contact microphone will be improved and its performance tested. A small batch of prototypes will be manufactured.A commercially available acoustic-emission sensor will be developed that enables structural-health monitoring in environments with extreme temperatures or neutron radiation. It will help safekeep nuclear infrastructure, including commercial reactors and spent-fuel storage facilities.