An ultrasonic measurement system and its robotic deployment into vessels for the combined assessment of debris condition and water leakage

福岛第一核电站（Fukushima daiichi Nuclear Power Site，简称1F）的退役是日本的一项高度优先事项，全球的退役工作都有值得借鉴的经验。目前的情况是，反应堆被水淹没，燃料碎片的位置和分布是未知的。一个专门设计的机器人已经进入了安全壳，然而，进入受到严格限制。该项目将研究超声波测量系统及其机器人部署的潜力，以评估主安全壳和反应堆压力容器淹水区域的情况。超声波测量在这种应用中特别有吸引力，因为它们可以克服与水中能见度低相关的问题，此外，传感器体积小，对放射性不敏感。我们提出了三个超声波测量系统集成到一个紧凑的包适合机器人部署的发展。前两个传感器系统将测量大尺度（米）和小尺度（厘米）的流量。这将使泄漏点的位置和量化。当水不断被泵入反应堆时，这些物质就会存在。此外，超声波传感器阵列将被开发用于对容器内部成像，并对燃料碎片进行定位和量化。还将尝试对碎片内部进行成像，以发现其结构完整性。这些信息最终将有助于安全清除残骸。这些测量系统将被构建并集成到机器人平台中，并在实验室复制品上进行测试。该项目将结合日本在超声波流量测量和机器人方面的专业知识，以及英国在超声波成像方面的专业知识。这项研究将为福岛第一核电站1F反应堆的退役奠定基础，并为英国和世界各地的退役活动提供宝贵的新技术和专业知识。

The decommissioning of the Fukushima Dai-ichi Nuclear Power Site (1F) is a high priority for Japan and there are lessons to be learned for decommissioning across the globe. The current situation is that the reactor is flooded with water and the location and distribution of the fuel debris is unknown. A specially designed robot has gained entry to the containment vessel, however, access is severely restricted. This project will investigate the potential of an ultrasonic measurement system and its robotic deployment to assess the conditions within the flooded regions of the primary containment vessel and reactor pressure vessel. Ultrasonic measurements are particularly attractive in this application as they can overcome the problems associated with poor visibility in the water in addition to which the sensors are small and insensitive to radioactivity. We propose the development of three ultrasonic measurement systems integrated into a compact package suitable for robotic deployment. The first two sensor systems will measure flow on a large-scale (meters) and on a smaller-scale (centimetres). This will enable the location and quantification of leakage points. These are known to exist as water is currently being continuously pumped into the reactor. In addition ultrasonic sensor arrays will be developed to image the interior of the vessels and locate and quantify the fuel debris. Attempts will also be made to image inside the debris to discover its structural integrity. This information will ultimately feed into attempts to safely remove the debris. These measurement systems will be built and integrated into a robotic platform and tested on a laboratory-based replica. The project will combine expertise on ultrasonic flow measurement and robotics from Japan with expertise on ultrasonic imaging from the UK. The research will lay the foundation for the decommissioning of the Fukushima Dai-ichi 1F reactor and provide valuable new techniques and expertise for decommissioning activities in the UK and around the world.