UNION (Ultrasonic Nuclear InspectiON)

目标是实现核能发电和后处理工厂管道输送冷却水或发电机蒸汽的无损检测（NDI），沿着管道运行，嵌入在混凝土中，埋在地下和/或覆盖在保护涂层，如塑料或沥青。主要的例子是(i)一次冷却剂和蒸汽管道分别穿过混凝土的一次和二次安全壳壁；（ii）用于乏燃料冷却的管道。这些管道的任何破坏都有核辐射泄漏的风险，并会关闭维修。嵌入/包覆材料都是高度衰减的超声波，使得目前核电站的超声波NDI实践无法使用或需要去除包覆。创新的解决方案是使用低频引导超声（LFGU），它可以在嵌入和包层材料中传播，用于定期检查和连续结构健康监测模式。通过新型高功率换能器和低噪声接收器，结合用于趋势分析的先进信号处理，增强了信噪比，可以检测到比LFGU迄今为止可能检测到的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.