燃料棒包壳超声导波检测技术研究

Research on Ultrasonic Guided Wave Testing Technology for Fuel Rod Cladding

摘要:

燃料棒包壳作为核电能源的关键部件，具有小直径、薄壁的结构特点。针对燃料棒包壳结构损伤检测，围绕燃料棒包壳结构的超声导波的检测机理，提出了基于宽带激励的超声导波检测优选频带方法，揭示了超声导波多模态、频散特性对于损伤的敏感性。针对燃料棒包壳结构裂纹损伤检测，通过多尺度缺陷的超声导波仿真研究，揭示了激励信号中心频率、裂纹位置和裂纹深度的内在关联规律，建立了裂纹损伤的评级方法，从而为损伤特征的辨识和诊断提供依据。实验研究表明，优选频带超声导波对燃料棒包壳结构表面裂纹具有较灵敏度，基于透射和反射信号能量特征可对裂纹等级进行精准划分，为燃料棒包壳结构的损伤检测和结构健康监测提供思路。

Abstract:

Fuel rod cladding, as a critical component of nuclear power systems, features a structure characterized by small diameter and thin walls. Aiming at defect detection of fuel rod cladding structures and based on the detection mechanism of ultrasonic guided waves, an optimal frequency band selection method for ultrasonic guided wave detection using broadband excitation is proposed. The sensitivity of ultrasonic guided waves' multimodal and dispersion characteristics to damage is revealed. For the early detection of cracks in fuel rod cladding structures, through multi-scale defect ultrasonic guided wave simulation studies, the intrinsic correlation between the excitation signal center frequency, crack location, and crack depth is revealed, and a crack damage rating method is established, thereby providing a basis for the identification and diagnosis of damage characteristics. Experimental studies indicate that the optimal frequency band of ultrasonic guided waves exhibits high sensitivity to surface cracks in fuel rod cladding structures. Based on the energy characteristics of transmitted and reflected signals, crack grades can be precisely classified, providing insights for damage detection and structural health monitoring of fuel rod cladding structures.