UNION (Ultrasonic Nuclear InspectiON)

目标是实现对核电厂和后处理厂输送冷却水或发电机蒸汽的管道系统的无损检测（NDI），这些管道系统沿着埋在混凝土中、埋在地下和/或覆盖有塑料或沥青等保护涂层的管道运行。主要的例子是（一）分别穿过混凝土一级和二级安全壳壁的一级冷却剂和蒸汽管道;以及（二）乏燃料冷却管道。这些管道的任何破裂都有核辐射泄漏的风险，需要关闭维修。嵌入/包层材料都高度衰减超声波，使得核电站中的当前超声波NDI实践不可用或需要去除包层。创新的解决方案是在定期检查和连续结构健康监测模式中使用低频引导超声（LFGU），它可以通过嵌入和包覆材料传播。通过新的高功率传感器和低噪声接收器结合先进的信号处理进行趋势分析，提高了信噪比，与LFGU相比，可以检测到更小的裂纹和腐蚀缺陷。

The goal is to achieve nondestructive inspection (NDI) of nuclear power generation and reprocessing plant pipework carrying cooling water or generator steam, along pipe runs that are embedded in concrete, buried underground and/or clad in protective coatings such as plastic or bitumen. Key examples are (i) primary coolant and steamline pipework passing respectively through the concrete primary and secondary containment walls; and (ii) pipework for spent fuel cooling. Any breach of these pipes carries risks of nuclear radiation leakage and shut down for repair. Embedding/cladding materials all highly attenuate ultrasound, making current ultrasonic NDI practice in nuclear plant unusable or requiring cladding removal. The innovative solution is to use low frequency guided ultrasonics (LFGU), which can propagate through embedding and cladding materials, in both periodic inspection and continuous structural health monitoring modes. Enhanced signal to noise ratios through new high power transducers and low noise receiver combined with advanced signal processing for trend analysis will allow detection of smaller crack and corrosion defects than hitherto possible by LFGU.