Abstract:Aiming at the problems of small target characteristics, blurred boundaries, and high false detection rates in the wear detection of nuclear reactor control rod guide cards, a detection method for guide card wear is investigated. Based on the YOLOv5s model, a lightweight backbone network, VoVNetv2s, is adopted to replace the original CSPDarkNet architecture. A convolutional spatial attention mechanism is embedded into the one-stage aggregation module, while a decoupled detection head is introduced to separate classification and localization tasks. In addition, the Efficient IoU (EIoU) loss function is employed to improve bounding box regression accuracy. Experimental results show that the proposed method achieves 98.9% mAP@0.5, 87.7% mAP@0.5:0.95, and 96.2% recall, with an inference speed of 168 FPS and a model size of 6.31 M parameters. The results demonstrate that the proposed approach enables high-precision real-time detection of guide card surface wear, meeting the requirements of reliability and real-time performance for nuclear reactor equipment inspection applications.