COMPUTATIONAL MODELING OF HIGH-TEMPERATURE MEMS SENSOR ARRAY FOR ULTRASONICS AND ACOUSTIC EMISSION IN STRUCTURAL HEALTH MONITORING OF HIGH TEMPERATURE ADVANCED REACTOR PIPES

Abstract

In recent years, development of advanced liquid metal thermal hydraulics enabling technologies has become increasingly important for commercial deployment of advanced reactors. One of the challenges is the need for reliable structural health monitoring (SHM) systems capable of detecting early signs of critical metallic structure failure in high-temperature environments. To address this need, we investigate a new type of piezoelectric microelectromechanical system (MEMS) sensor that can continuously operate at high temperatures. We study the use of a circumferential array of high-temperature piezoelectric MEMS sensors for deployment on a piping system of Argonne’s Mechanisms Engineering Test Loop (METL) liquid sodium thermal hydraulic facility. The MEMS sensors consist of square silicon carbide wafer with 5 mm length and aluminum nitride as piezoelectric element. These materials were shown to be resilient to ionizing nuclear radiation in prior studies. The sensors are arranged in a circumferential array on the pipe surface to enable dual ultrasonics and acoustic emission sensing. To determine the optimal number of transducers needed to achieve the excitation of Lamb wave for ultrasonics testing, we created a Multiphysics numerical model to simulate the coupling between the sensors and the pipe. Overall, the results of the study demonstrated the potential of using high-temperature piezoelectric MEMS sensors for SHM in liquid metal reactors. By detecting critical structure failure in high-temperature environments, these sensors could help reduce the risk of forced reactor shutdown and minimize operation and maintenance costs.