Accurate and timely assessment of displacements and/or structural damages in nuclear reactor vessels’ components is a key action in routine inspections for planning maintenance and repairs but also in emergency situations for mitigating consequences of nuclear incidents. Nevertheless, all these components are maintained underwater and reside in high-radiation fields thus imposing harsh operative conditions to inspection devices which must cope with effects such as Cerenkov radiation background, Total Ionizing Radiation (TID), and occlusions in the detectors’ field of view. To date, ultrasonic techniques and video cameras are in use for inspection of components’ integrity and with measurements of volumetric and surface crack opening displacements, respectively. The present work reports the realization of a radiation tolerant laser scanner and the results of tests in a nuclear research reactor vessel for acquisition of 3D models of critical components. The device, qualified for underwater operation and for withstanding up to 1 mGy of TID, is based on a 515 nm laser diode and a fast-scanning electro-optic unit. To evaluate performances in a significant but controlled environment, the device has been deployed in the vessel of a research reactor operated by ENEA in the Casaccia Research Centre in Rome (Italy). A 3D model of the fuel rods assembly through a cooling water column of 7 m has been acquired. The system includes proprietary postprocessing software that automatically recognizes components of interest and provides dimensional analysis. Possible application fields of the system stretch to dimensional analysis also in spent nuclear fuel storage pools.

中文翻译：

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用于核反应堆容器和燃料储存池结构检查的耐辐射 3D 激光扫描仪

准确及时地评估核反应堆容器部件的位移和/或结构损坏是计划维护和维修的例行检查中的关键行动，也是减轻核事故后果的紧急情况下的关键行动。然而，所有这些组件都保持在水下并位于高辐射场中，因此对必须应对诸如切伦科夫辐射背景、总电离辐射 (TID) 和探测器视场遮挡等影响的检查设备施加了恶劣的操作条件. 迄今为止，超声波技术和摄像机分别用于检查部件的完整性以及测量体积和表面裂纹张开位移。目前的工作报告了耐辐射激光扫描仪的实现以及在核研究反应堆容器中获得关键部件 3D 模型的测试结果。该设备符合水下操作要求，可承受高达 1 mGy 的 TID，基于 515 nm 激光二极管和快速扫描电光单元。为了在重要但受控的环境中评估性能，该设备已部署在由 ENEA 运营的位于罗马（意大利）Casaccia 研究中心的研究反应堆的容器中。通过 7 m 的冷却水柱获得了燃料棒组件的 3D 模型。该系统包括专有的后处理软件，可自动识别感兴趣的组件并提供尺寸分析。