EFFICIENT AND SAFE FUEL DEBRIS RETRIEVAL UTILISING LONG-REACH MANIPULATORS THROUGH ADVANCED CONTROL TECHNIQUES & MOTION PLANNING

Abstract

A long-reach robotic system is developed for fuel debris retrieval operations at Fukushima Daiichi. The system has a hyper-redundant kinematic design resulting in high dexterity to access cluttered decommissioning environments inside the primary contaminated vessels. The long-reach system is in a slender design to allow for ease of accessing narrow ports and navigating through congestion. Similar to other long-reach systems for nuclear decommissioning operations, the long-reach system design results in significant flexibility, causing deformation and vibrations. The kinematic hyper-redundancy makes it challenging to plan motion sequences, taking into account space constraints and other safety-related considerations. Motivated to realise safe and efficient fuel debris retrieval, it is necessary to tackle essential technical gaps in the control and operation of the long-reach manipulator. In response, a series of research and development projects have been conducted to reduce risks in controlling the long-reach system and to provide operation teams with assistive features to plan operations, by leveraging state-of-the-art from other sectors. This addresses the key technological gaps paving the way towards retrieving fuel debris in engineering practice.