ASUNDER - Adaptable Semiautonomous Underwater Decommissioning Sample Retrieval Robot

在核工业中，有许多遗留地点包含被淹没的设施，例如日本福岛第一核电站1号机组的主要容器，以及英国塞拉菲尔德的储存池。这些被淹没的地点通常含有或曾经含有高放射性物质，因此具有高度危险性。作为这些设施退役战略的一部分，有必要确认这些淹没区域内材料的特性，以便尽可能安全地将其移除。无论是为了验证，还是其他原因，在某些时候，有必要从材料中取出一小部分样品进行实验室测试，这可能涉及确定样品的机械、化学或放射特性。由于环境的危险性，这种样品采集不能人工进行。然而，能够完成这项任务的机器人系统是不可用的，因为大多数用于水下退役的切割工具都是为大规模拆除结构而开发的，因此不适合这项任务。此外，这些工具通常需要固定在被切割的结构上，以适应产生的力。这种方法不能在这种情况下使用。该项目提出了一种新的解决方案，即基于无人水下航行器（UUV）的机器人机械手将用于定位和定向水下切割工具，以半自主地去除样品。这样的系统将能够进入几乎任何水下环境，并在其他系统无法检索样本。该系统意味着切削刀具不需要固定，减少了人工干预的需要，使加工过程更加安全。在粒子悬浮引起的浑浊条件下，将利用虚拟现实技术向操作员提供声纳数据来实现导航。声纳数据还将支持机械臂上的成像系统，用于通知和监测局部切割过程。同时还将评估辐射环境，以便为决策提供信息，例如确定堆芯的位置或其性质。为了实现这一目标，将开发并集成一种新型的紧凑型中子传感器，该传感器能够估计水下的剂量率和中子能谱。附加的传感和反馈系统将用于监控机械手关节和末端执行器的位置和方向。这将包括有关机械臂上的流体动力载荷的信息。一种基于机械手逆动力学的自适应半自主控制算法将被开发和实施，该算法将补偿流体动力和UUV的运动，以确保切割操作有效地继续进行。末端执行器将包括一个样品检索工具，以及一个切割工具。这允许这些工具协同工作，同时将重量和复杂性降至最低。其目的是使控制策略具有适应性，并允许根据需要结合其他工具，以适应退役策略的发展。该系统将包括一个完整的端到端解决方案，并在日本和英国的实际条件下进行验证。

There are many legacy sites within the nuclear industry that contain facilities that are submerged, such as the primary contain vessels in Unit 1 of the Fukushima Daiichi Nuclear Power Plant in Japan, and the storage ponds at Sellafield in the UK. These submerged sites often contain, or have contained, highly radioactive materials and as such are highly hazardous. As part of the decommissioning strategy of these facilities, it is necessary to confirm the properties of the materials within these submerged areas, so that they can be removed as safely as possible. Whether it be for validation, or other reasons, at some point it is necessary to remove a small sample of the material for lab-based testing, which may involve determining the mechanical, chemical or radiological properties of the sample. Due to the hazardous nature of the environment, such sample collection cannot be conducted manually. However, robotic systems capable of this task are not available, as most cutting tools for underwater decommissioning were developed for the large-scale removal of structures and hence, are not suitable for the task. Also, these tools often need to be secured to the structure being cut to accommodate the forces generated. This methodology cannot be employed in this scenario. This project proposes a new solution, whereby an unmanned underwater vehicle (UUV) based robotic manipulator will be used to position and orientate underwater cutting tools to remove samples semiautonomously. Such a system will be able to access almost any submerged environment and retrieve samples where no other system could. This system would mean that the cutting tool will not need to be secured, reducing the need for manual intervention, making the process much safer. Navigation in the turbid conditions caused by particle suspension will be achieved using sonar data presented to the operator using virtual reality. The sonar data will also support imaging systems on the manipulator used to inform and monitor the cutting process locally. The radiological environment will also be assessed concurrently to inform decision making, such as the identification of the corium position or its nature. To achieve this, a novel compact neutron sensor capable of estimating the dose rate and neutron energy spectrum underwater will be developed and integrated.Additional sensing and feedback systems will be used to monitor the position and orientation of the manipulator joints and end effectors. This will include information about the hydrodynamic loading on the manipulator. An adaptable semiautonomous control algorithm will be developed and implemented based on the inverse dynamics of the manipulator that will compensate for the hydrodynamic forces and the movement of the UUV to ensure the cutting operation continues efficiently. The end effector will incorporate a sample retrieval tool, as well as a cutting tool. This allows the tools to work collaboratively, whilst minimising weight and complexity. It is intended that the control strategy will be adaptable and will allow other tools to be incorporated as required as decommissioning strategies evolve. This system will comprise a complete end-to-end solution, validated in realistic conditions in both Japan and the UK.