Development of Advanced Gamma Imaging Systems for robot supported radiological mapping for Nuclear Decommissioning

Abstract

Nuclear decommissioning presents significant challenges due to the hazardous nature of radioactive environments and the need for precise radiological characterization. This thesis specifically addresses these challenges by advancing technologies for radiological characterization in nuclear decommissioning. The research focuses on developing advanced measurement techniques that can be integrated into robotic platforms with gamma imaging systems to improve efficiency, safety, and accuracy in radiological assessments. The primary objectives of this work are to (1) optimize measurement times, (2) develop a compact gamma imaging system for seamless integration with robotic platforms, (3) implement real-time data processing to enhance operational decisions, and (4) utilize commercially available components to ensure scalability. These goals aim to increase decommissioning efficiency while maintaining high safety and precision. Methodologically, the thesis centers on automated radiological mapping for the ARCHER (Autonomous Robot for Characterization) platform. Calibration techniques were employed to minimize measurement times when using a CdZnTe detector in both low- and high-background environments. Additionally, a lightweight gamma imaging system based on the Timepix3 detector was developed, optimized for rapid, high-resolution gamma-ray spectrometry and 3D hotspot mapping. Key findings include significant reductions in measurement times and improvements in hotspot localization accuracy. The Timepix3 gamma imaging system, designed for the ARCHER platform, enables efficient radiological mapping in hazardous, hard-to-reach areas. Real-time data processing further enhances operational safety and responsiveness. This thesis contributes to nuclear decommissioning by demonstrating how scalable, adaptable gamma imaging methods—integrated with robotic platforms— can improve overall safety and operational efficiency. Optimizing measurement times and employing off-the-shelf components render these systems costeffective and practical for various decommissioning applications. In conclusion, the research shows that robotic platforms combined with advanced gamma imaging significantly enhance the safety, accuracy, and efficiency of nuclear decommissioning.